[转载]Spring Boot Actuator 使用

àì夳堔傛蜴生んèń 2022-09-05 04:25 125阅读 0赞

> 作者：FlySheep\_ly  
> 链接：https://www.jianshu.com/p/af9738634a21  
> 来源：简书

Spring Boot 的 Actuator 提供了很多生产级的特性，比如监控和度量Spring Boot 应用程序。Actuator 的这些特性可以通过众多 REST 接口、远程 shell 和 JMX 获得。

### 一、Actuator 的 REST 接口 ###

Spring Boot Actuator 的关键特性是在应用程序里提供众多 Web 接口，通过它们了解应用程序运行时的内部状况。Actuator 提供了 13 个接口，可以分为三大类：配置接口、度量接口和其它接口，具体如下表所示。

<table> 
 <thead> 
  <tr> 
   <th>HTTP 方法</th> 
   <th>路径</th> 
   <th>描述</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td>GET</td> 
   <td>/autoconfig</td> 
   <td>提供了一份自动配置报告，记录哪些自动配置条件通过了，哪些没通过</td> 
  </tr> 
  <tr> 
   <td>GET</td> 
   <td>/configprops</td> 
   <td>描述配置属性(包含默认值)如何注入Bean</td> 
  </tr> 
  <tr> 
   <td>GET</td> 
   <td>/beans</td> 
   <td>描述应用程序上下文里全部的Bean，以及它们的关系</td> 
  </tr> 
  <tr> 
   <td>GET</td> 
   <td>/dump</td> 
   <td>获取线程活动的快照</td> 
  </tr> 
  <tr> 
   <td>GET</td> 
   <td>/env</td> 
   <td>获取全部环境属性</td> 
  </tr> 
  <tr> 
   <td>GET</td> 
   <td>/env/{name}</td> 
   <td>根据名称获取特定的环境属性值</td> 
  </tr> 
  <tr> 
   <td>GET</td> 
   <td>/health</td> 
   <td>报告应用程序的健康指标，这些值由HealthIndicator的实现类提供</td> 
  </tr> 
  <tr> 
   <td>GET</td> 
   <td>/info</td> 
   <td>获取应用程序的定制信息，这些信息由info打头的属性提供</td> 
  </tr> 
  <tr> 
   <td>GET</td> 
   <td>/mappings</td> 
   <td>描述全部的URI路径，以及它们和控制器(包含Actuator端点)的映射关系</td> 
  </tr> 
  <tr> 
   <td>GET</td> 
   <td>/metrics</td> 
   <td>报告各种应用程序度量信息，比如内存用量和HTTP请求计数</td> 
  </tr> 
  <tr> 
   <td>GET</td> 
   <td>/metrics/{name}</td> 
   <td>报告指定名称的应用程序度量值</td> 
  </tr> 
  <tr> 
   <td>POST</td> 
   <td>/shutdown</td> 
   <td>关闭应用程序，要求endpoints.shutdown.enabled设置为true</td> 
  </tr> 
  <tr> 
   <td>GET</td> 
   <td>/trace</td> 
   <td>提供基本的HTTP请求跟踪信息(时间戳、HTTP头等)</td> 
  </tr> 
 </tbody> 
</table>

要启用 Actuator 的端点，只要在项目中引入 Actuator 的依赖即可。对于 Maven 依赖，引入的依赖是这样的：

<dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-actuator</artifactId>
    </dependency>

#### 1. 查看配置明细 ####

Actuator 有一些接口不仅可以显示组件映射关系，还可以告诉你自动配置在配置 Spring 应用程序上下文时做了哪些决策。

##### 1.1 获得 Bean 装配报告 #####

要了解应用程序中 Spring 上下文的情况，最重要的接口就是 `/beans`。它会返回一个 JSON 文档，描述上下文里每个 bean 的情况，包括其 Java 类型以及注入的其它 bean。返回的信息如下所示：

[
        { 
            "context": "application",
            "parent": null,
            "beans": [
                { 
                    "bean": "demoApplication",
                    "aliases": [],
                    "scope": "singleton",
                    "type": "com.example.DemoApplication$$EnhancerBySpringCGLIB$$88686e04",
                    "resource": "null",
                    "dependencies": []
                },
                { 
                    "bean": "org.springframework.boot.autoconfigure.internalCachingMetadataReaderFactory",
                    "aliases": [],
                    "scope": "singleton",
                    "type": "org.springframework.core.type.classreading.CachingMetadataReaderFactory",
                    "resource": "null",
                    "dependencies": []
                }
            ]
        }
    ]

所有的 Bean 条目都有五类信息：

*  bean：Spring 应用程序上下文中的 Bean 名称或 ID。
 *  resource：.class 文件的物理位置，通常是一个 URL，指向构建出的 JAR 文件。这会随着应用程序的构建和运行方式发生变化。
 *  dependencies：当前 Bean 注入的 Bean ID 列表。
 *  scope：Bean 的作用域（通常是单例，这也是默认作用域）。
 *  type：Bean 的 Java 类型。

##### 1.2 详解自动配置 #####

`/autoconfig`接口能告诉你为什么会有这个 bean ，或者为什么没有这个 bean。

{ 
        "positiveMatches": { 
            "AuditAutoConfiguration#auditListener": [
                { 
                    "condition": "OnBeanCondition",
                    "message": "@ConditionalOnMissingBean (types: org.springframework.boot.actuate.audit.listener.AbstractAuditListener; SearchStrategy: all) did not find any beans"
                }
            ],
            "MultipartAutoConfiguration#multipartConfigElement": [
                { 
                    "condition": "OnBeanCondition",
                    "message": "@ConditionalOnMissingBean (types: javax.servlet.MultipartConfigElement; SearchStrategy: all) did not find any beans"
                }
            ]
        },
        "negativeMatches": { 
            "AuditAutoConfiguration#authenticationAuditListener": { 
                "notMatched": [
                    { 
                        "condition": "OnClassCondition",
                        "message": "@ConditionalOnClass did not find required class 'org.springframework.security.authentication.event.AbstractAuthenticationEvent'"
                    }
                ],
                "matched": []
            },
            "AuditAutoConfiguration#authorizationAuditListener": { 
                "notMatched": [
                    { 
                        "condition": "OnClassCondition",
                        "message": "@ConditionalOnClass did not find required class 'org.springframework.security.access.event.AbstractAuthorizationEvent'"
                    }
                ],
                "matched": []
            }
        }
    }

##### 1.3 查看配置属性 #####

`/env`接口会生成应用程序可用的所有环境属性的列表，无论这些属性是否用到。这其中包括环境变量、JVM 属性、命令行参数，以及 application.properties 或 application.yml 文件提供的属性。

{ 
        "profiles": [],
        "server.ports": { 
            "local.server.port": 8080
        },
        "servletContextInitParams": { },
        "systemProperties": { 
            "java.runtime.name": "Java(TM) SE Runtime Environment",
            "spring.output.ansi.enabled": "always",
            "sun.boot.library.path": "/Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/jre/lib",
            "java.vm.version": "25.121-b13",
            "gopherProxySet": "false",
            "java.vm.vendor": "Oracle Corporation",
            "java.vendor.url": "http://java.oracle.com/",
            "path.separator": ":",
            "idea.launcher.port": "7532",
            "java.vm.name": "Java HotSpot(TM) 64-Bit Server VM",
            "file.encoding.pkg": "sun.io",
            "user.country": "CN",
            "sun.java.launcher": "SUN_STANDARD",
            "sun.os.patch.level": "unknown",
            "PID": "2716",
            "java.vm.specification.name": "Java Virtual Machine Specification",
            "user.dir": "/Users/FlySheep/FlySheep/Code/ServerCode/SpringBoot_Demo/demo",
            "java.runtime.version": "1.8.0_121-b13",
            "java.awt.graphicsenv": "sun.awt.CGraphicsEnvironment",
            "org.jboss.logging.provider": "slf4j",
            "java.endorsed.dirs": "/Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/jre/lib/endorsed",
            "os.arch": "x86_64",
            "visualvm.id": "11136812717769",
            "java.io.tmpdir": "/var/folders/d6/zn9yrwns46j4pwbl1_mv_6hw0000gn/T/",
            "line.separator": "\n",
            "java.vm.specification.vendor": "Oracle Corporation",
            "os.name": "Mac OS X",
            "sun.jnu.encoding": "UTF-8",
            "spring.beaninfo.ignore": "true",
            "java.library.path": "/Users/FlySheep/Library/Java/Extensions:/Library/Java/Extensions:/Network/Library/Java/Extensions:/System/Library/Java/Extensions:/usr/lib/java:.",
            "java.specification.name": "Java Platform API Specification",
            "java.class.version": "52.0",
            "sun.management.compiler": "HotSpot 64-Bit Tiered Compilers",
            "os.version": "10.11",
            "user.home": "/Users/FlySheep",
            "catalina.useNaming": "false",
            "user.timezone": "Asia/Shanghai",
            "java.awt.printerjob": "sun.lwawt.macosx.CPrinterJob",
            "file.encoding": "UTF-8",
            "idea.launcher.bin.path": "/Applications/IntelliJ IDEA.app/Contents/bin",
            "java.specification.version": "1.8",
            "catalina.home": "/private/var/folders/d6/zn9yrwns46j4pwbl1_mv_6hw0000gn/T/tomcat.6698906163877756728.8080",
            "java.class.path": "/Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/jre/lib/charsets.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/jre/lib/deploy.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/jre/lib/ext/cldrdata.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/jre/lib/ext/dnsns.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/jre/lib/ext/jaccess.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/jre/lib/ext/jfxrt.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/jre/lib/ext/localedata.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/jre/lib/ext/nashorn.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/jre/lib/ext/sunec.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/jre/lib/ext/sunjce_provider.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/jre/lib/ext/sunpkcs11.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/jre/lib/ext/zipfs.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/jre/lib/javaws.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/jre/lib/jce.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/jre/lib/jfr.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/jre/lib/jfxswt.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/jre/lib/jsse.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/jre/lib/management-agent.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/jre/lib/plugin.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/jre/lib/resources.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/jre/lib/rt.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/lib/ant-javafx.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/lib/dt.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/lib/javafx-mx.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/lib/jconsole.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/lib/packager.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/lib/sa-jdi.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/lib/tools.jar:/Users/FlySheep/FlySheep/Code/ServerCode/SpringBoot_Demo/demo/target/classes:/Users/FlySheep/.m2/repository/org/springframework/boot/spring-boot-starter-web/1.5.2.RELEASE/spring-boot-starter-web-1.5.2.RELEASE.jar:/Users/FlySheep/.m2/repository/org/springframework/boot/spring-boot-starter/1.5.2.RELEASE/spring-boot-starter-1.5.2.RELEASE.jar:/Users/FlySheep/.m2/repository/org/springframework/boot/spring-boot/1.5.2.RELEASE/spring-boot-1.5.2.RELEASE.jar:/Users/FlySheep/.m2/repository/org/springframework/boot/spring-boot-autoconfigure/1.5.2.RELEASE/spring-boot-autoconfigure-1.5.2.RELEASE.jar:/Users/FlySheep/.m2/repository/org/springframework/boot/spring-boot-starter-logging/1.5.2.RELEASE/spring-boot-starter-logging-1.5.2.RELEASE.jar:/Users/FlySheep/.m2/repository/ch/qos/logback/logback-classic/1.1.11/logback-classic-1.1.11.jar:/Users/FlySheep/.m2/repository/ch/qos/logback/logback-core/1.1.11/logback-core-1.1.11.jar:/Users/FlySheep/.m2/repository/org/slf4j/jcl-over-slf4j/1.7.24/jcl-over-slf4j-1.7.24.jar:/Users/FlySheep/.m2/repository/org/slf4j/jul-to-slf4j/1.7.24/jul-to-slf4j-1.7.24.jar:/Users/FlySheep/.m2/repository/org/slf4j/log4j-over-slf4j/1.7.24/log4j-over-slf4j-1.7.24.jar:/Users/FlySheep/.m2/repository/org/yaml/snakeyaml/1.17/snakeyaml-1.17.jar:/Users/FlySheep/.m2/repository/org/springframework/boot/spring-boot-starter-tomcat/1.5.2.RELEASE/spring-boot-starter-tomcat-1.5.2.RELEASE.jar:/Users/FlySheep/.m2/repository/org/apache/tomcat/embed/tomcat-embed-core/8.5.11/tomcat-embed-core-8.5.11.jar:/Users/FlySheep/.m2/repository/org/apache/tomcat/embed/tomcat-embed-el/8.5.11/tomcat-embed-el-8.5.11.jar:/Users/FlySheep/.m2/repository/org/apache/tomcat/embed/tomcat-embed-websocket/8.5.11/tomcat-embed-websocket-8.5.11.jar:/Users/FlySheep/.m2/repository/org/hibernate/hibernate-validator/5.3.4.Final/hibernate-validator-5.3.4.Final.jar:/Users/FlySheep/.m2/repository/javax/validation/validation-api/1.1.0.Final/validation-api-1.1.0.Final.jar:/Users/FlySheep/.m2/repository/org/jboss/logging/jboss-logging/3.3.0.Final/jboss-logging-3.3.0.Final.jar:/Users/FlySheep/.m2/repository/com/fasterxml/classmate/1.3.3/classmate-1.3.3.jar:/Users/FlySheep/.m2/repository/com/fasterxml/jackson/core/jackson-databind/2.8.7/jackson-databind-2.8.7.jar:/Users/FlySheep/.m2/repository/com/fasterxml/jackson/core/jackson-annotations/2.8.0/jackson-annotations-2.8.0.jar:/Users/FlySheep/.m2/repository/com/fasterxml/jackson/core/jackson-core/2.8.7/jackson-core-2.8.7.jar:/Users/FlySheep/.m2/repository/org/springframework/spring-web/4.3.7.RELEASE/spring-web-4.3.7.RELEASE.jar:/Users/FlySheep/.m2/repository/org/springframework/spring-aop/4.3.7.RELEASE/spring-aop-4.3.7.RELEASE.jar:/Users/FlySheep/.m2/repository/org/springframework/spring-beans/4.3.7.RELEASE/spring-beans-4.3.7.RELEASE.jar:/Users/FlySheep/.m2/repository/org/springframework/spring-context/4.3.7.RELEASE/spring-context-4.3.7.RELEASE.jar:/Users/FlySheep/.m2/repository/org/springframework/spring-webmvc/4.3.7.RELEASE/spring-webmvc-4.3.7.RELEASE.jar:/Users/FlySheep/.m2/repository/org/springframework/spring-expression/4.3.7.RELEASE/spring-expression-4.3.7.RELEASE.jar:/Users/FlySheep/.m2/repository/org/springframework/boot/spring-boot-starter-actuator/1.5.2.RELEASE/spring-boot-starter-actuator-1.5.2.RELEASE.jar:/Users/FlySheep/.m2/repository/org/springframework/boot/spring-boot-actuator/1.5.2.RELEASE/spring-boot-actuator-1.5.2.RELEASE.jar:/Users/FlySheep/.m2/repository/org/slf4j/slf4j-api/1.7.24/slf4j-api-1.7.24.jar:/Users/FlySheep/.m2/repository/org/springframework/spring-core/4.3.7.RELEASE/spring-core-4.3.7.RELEASE.jar:/Applications/IntelliJ IDEA.app/Contents/lib/idea_rt.jar",
            "user.name": "FlySheep",
            "java.vm.specification.version": "1.8",
            "sun.java.command": "com.intellij.rt.execution.application.AppMain com.example.DemoApplication",
            "java.home": "/Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/jre",
            "sun.arch.data.model": "64",
            "user.language": "zh",
            "java.specification.vendor": "Oracle Corporation",
            "awt.toolkit": "sun.lwawt.macosx.LWCToolkit",
            "java.vm.info": "mixed mode",
            "java.version": "1.8.0_121",
            "java.ext.dirs": "/Users/FlySheep/Library/Java/Extensions:/Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/jre/lib/ext:/Library/Java/Extensions:/Network/Library/Java/Extensions:/System/Library/Java/Extensions:/usr/lib/java",
            "sun.boot.class.path": "/Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/jre/lib/resources.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/jre/lib/rt.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/jre/lib/sunrsasign.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/jre/lib/jsse.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/jre/lib/jce.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/jre/lib/charsets.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/jre/lib/jfr.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/jre/classes",
            "java.awt.headless": "true",
            "java.vendor": "Oracle Corporation",
            "catalina.base": "/private/var/folders/d6/zn9yrwns46j4pwbl1_mv_6hw0000gn/T/tomcat.6698906163877756728.8080",
            "file.separator": "/",
            "java.vendor.url.bug": "http://bugreport.sun.com/bugreport/",
            "sun.io.unicode.encoding": "UnicodeBig",
            "sun.cpu.endian": "little",
            "sun.cpu.isalist": ""
        },
        "systemEnvironment": { 
            "PATH": "/usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin:/Library/Java/JavaVirtualMachines/jdk1.7.0_79.jdk/Contents/Home/bin:/usr/local/mysql/bin:/Users/FlySheep/FlySheep/JavaTools/apache-maven-3.3.9/bin/bin",
            "SHELL": "/bin/zsh",
            "PAGER": "less",
            "LSCOLORS": "Gxfxcxdxbxegedabagacad",
            "OLDPWD": "/Applications/IntelliJ IDEA.app/Contents/bin",
            "USER": "FlySheep",
            "VERSIONER_PYTHON_PREFER_32_BIT": "no",
            "ZSH": "/Users/FlySheep/.oh-my-zsh",
            "TMPDIR": "/var/folders/d6/zn9yrwns46j4pwbl1_mv_6hw0000gn/T/",
            "SSH_AUTH_SOCK": "/private/tmp/com.apple.launchd.vZEKsGdZ1T/Listeners",
            "JAVA_MAIN_CLASS_2716": "com.intellij.rt.execution.application.AppMain",
            "XPC_FLAGS": "0x0",
            "VERSIONER_PYTHON_VERSION": "2.7",
            "__CF_USER_TEXT_ENCODING": "0x1F5:0x19:0x34",
            "Apple_PubSub_Socket_Render": "/private/tmp/com.apple.launchd.5VgRuDCQ5D/Render",
            "LOGNAME": "FlySheep",
            "LESS": "-R",
            "LC_CTYPE": "",
            "PWD": "/Users/FlySheep/FlySheep/Code/ServerCode/SpringBoot_Demo/demo",
            "XPC_SERVICE_NAME": "com.jetbrains.intellij.136992",
            "HOME": "/Users/FlySheep"
        },
        "applicationConfig: [classpath:/application.properties]": { 
            "management.security.enabled": "false"
        }
    }

基本上，任何能给Spring Boot 应用程序提供属性的属性源都会列在 /env 的结果里，同时会显示具体的属性。  
　为了避免敏感信息暴露到 /env 里，所有名为password、secret、key(或者名字中最后一段是这些)的属性在 /env 里都会加上“\*”。举个例子，如果有一个属性名字是database.password，那么它在/env中的显示效果是这样的：

"database.password":"******"

/env 接口还能用来获取单个属性的值，只需要在请求时在 /env 后加上属性名即可。

##### 1.4 查看属性的使用方法 #####

/configprops 接口会生成一个报告，说明属性如何进行设置(注入或其他方式)。

{ 
        "endpoints-org.springframework.boot.actuate.endpoint.EndpointProperties": { 
            "prefix": "endpoints",
            "properties": { 
                "enabled": true,
                "sensitive": null
            }
        },
        "management.info-org.springframework.boot.actuate.autoconfigure.InfoContributorProperties": { 
            "prefix": "management.info",
            "properties": { 
                "git": { 
                    "mode": "SIMPLE"
                }
            }
        },
        "metricsEndpoint": { 
            "prefix": "endpoints.metrics",
            "properties": { 
                "id": "metrics",
                "sensitive": true,
                "enabled": true
            }
        },
        "spring.jackson-org.springframework.boot.autoconfigure.jackson.JacksonProperties": { 
            "prefix": "spring.jackson",
            "properties": { 
                "propertyNamingStrategy": null,
                "defaultPropertyInclusion": null,
                "dateFormat": null,
                "timeZone": null,
                "locale": null,
                "jodaDateTimeFormat": null
            }
        },
        "heapdumpMvcEndpoint": { 
            "prefix": "endpoints.heapdump",
            "properties": { 
                "path": "/heapdump",
                "sensitive": true,
                "enabled": true
            }
        },
        "endpoints.cors-org.springframework.boot.actuate.autoconfigure.EndpointCorsProperties": { 
            "prefix": "endpoints.cors",
            "properties": { 
                "allowedOrigins": [],
                "maxAge": 1800,
                "exposedHeaders": [],
                "allowedHeaders": [],
                "allowedMethods": [],
                "allowCredentials": null
            }
        },
        "environmentMvcEndpoint": { 
            "prefix": "endpoints.env",
            "properties": { 
                "path": "/env"
            }
        },
        "environmentEndpoint": { 
            "prefix": "endpoints.env",
            "properties": { 
                "id": "env",
                "sensitive": true,
                "enabled": true
            }
        },
        "spring.http.multipart-org.springframework.boot.autoconfigure.web.MultipartProperties": { 
            "prefix": "spring.http.multipart",
            "properties": { 
                "maxRequestSize": "10MB",
                "fileSizeThreshold": "0",
                "location": null,
                "maxFileSize": "1MB",
                "enabled": true,
                "resolveLazily": false
            }
        },
        "spring.info-org.springframework.boot.autoconfigure.info.ProjectInfoProperties": { 
            "prefix": "spring.info",
            "properties": { 
                "build": { 
                    "location": { }
                },
                "git": { 
                    "location": { }
                }
            }
        },
        "auditEventsEndpoint": { 
            "prefix": "endpoints.auditevents",
            "properties": { 
                "enabled": true
            }
        },
        "traceEndpoint": { 
            "prefix": "endpoints.trace",
            "properties": { 
                "id": "trace",
                "sensitive": true,
                "enabled": true
            }
        },
        "metricsMvcEndpoint": { 
            "prefix": "endpoints.metrics",
            "properties": { 
                "path": "/metrics"
            }
        },
        "infoEndpoint": { 
            "prefix": "endpoints.info",
            "properties": { 
                "id": "info",
                "sensitive": false,
                "enabled": true
            }
        },
        "auditEventMvcEndpoint": { 
            "prefix": "endpoints.auditevents",
            "properties": { 
                "path": "/auditevents",
                "sensitive": true,
                "enabled": true
            }
        },
        "management.trace-org.springframework.boot.actuate.trace.TraceProperties": { 
            "prefix": "management.trace",
            "properties": { 
                "include": [
                    "COOKIES",
                    "REQUEST_HEADERS",
                    "RESPONSE_HEADERS",
                    "ERRORS"
                ]
            }
        },
        "spring.resources-org.springframework.boot.autoconfigure.web.ResourceProperties": { 
            "prefix": "spring.resources",
            "properties": { 
                "cachePeriod": null,
                "addMappings": true,
                "chain": { 
                    "cache": true,
                    "htmlApplicationCache": false,
                    "gzipped": false,
                    "strategy": { 
                        "fixed": { 
                            "enabled": false,
                            "paths": [
                                "/**"
                            ],
                            "version": null
                        },
                        "content": { 
                            "enabled": false,
                            "paths": [
                                "/**"
                            ]
                        }
                    }
                },
                "staticLocations": [
                    "/",
                    "classpath:/META-INF/resources/",
                    "classpath:/resources/",
                    "classpath:/static/",
                    "classpath:/public/"
                ]
            }
        },
        "management.health.status-org.springframework.boot.actuate.autoconfigure.HealthIndicatorProperties": { 
            "prefix": "management.health.status",
            "properties": { 
                "order": null
            }
        },
        "healthMvcEndpoint": { 
            "prefix": "endpoints.health",
            "properties": { 
                "path": "/health"
            }
        },
        "serverProperties": { 
            "prefix": "server",
            "properties": { 
                "address": null,
                "maxHttpPostSize": 0,
                "undertow": { 
                    "maxHttpPostSize": 0,
                    "bufferSize": null,
                    "buffersPerRegion": null,
                    "ioThreads": null,
                    "workerThreads": null,
                    "directBuffers": null,
                    "accesslog": { 
                        "enabled": null,
                        "pattern": "common",
                        "prefix": "access_log.",
                        "suffix": "log",
                        "dir": "/Users/FlySheep/FlySheep/Code/ServerCode/SpringBoot_Demo/demo/logs",
                        "rotate": true
                    }
                },
                "tomcat": { 
                    "accesslog": { 
                        "enabled": false,
                        "pattern": "common",
                        "directory": "logs",
                        "prefix": "access_log",
                        "suffix": ".log",
                        "rotate": true,
                        "renameOnRotate": false,
                        "requestAttributesEnabled": false,
                        "buffered": true
                    },
                    "internalProxies": "10\\.\\d{1,3}\\.\\d{1,3}\\.\\d{1,3}|192\\.168\\.\\d{1,3}\\.\\d{1,3}|169\\.254\\.\\d{1,3}\\.\\d{1,3}|127\\.\\d{1,3}\\.\\d{1,3}\\.\\d{1,3}|172\\.1[6-9]{1}\\.\\d{1,3}\\.\\d{1,3}|172\\.2[0-9]{1}\\.\\d{1,3}\\.\\d{1,3}|172\\.3[0-1]{1}\\.\\d{1,3}\\.\\d{1,3}",
                    "protocolHeader": null,
                    "protocolHeaderHttpsValue": "https",
                    "portHeader": "X-Forwarded-Port",
                    "remoteIpHeader": null,
                    "basedir": null,
                    "backgroundProcessorDelay": 30,
                    "maxThreads": 0,
                    "minSpareThreads": 0,
                    "maxHttpPostSize": 0,
                    "redirectContextRoot": null,
                    "uriEncoding": null,
                    "maxConnections": 0,
                    "acceptCount": 0,
                    "additionalTldSkipPatterns": []
                },
                "displayName": "application",
                "session": { 
                    "timeout": null,
                    "trackingModes": null,
                    "persistent": false,
                    "storeDir": null,
                    "cookie": { 
                        "name": null,
                        "domain": null,
                        "path": null,
                        "comment": null,
                        "httpOnly": null,
                        "secure": null,
                        "maxAge": null
                    }
                },
                "contextPath": null,
                "error": { 
                    "path": "/error",
                    "includeStacktrace": "NEVER"
                },
                "ssl": null,
                "serverHeader": null,
                "useForwardHeaders": null,
                "port": null,
                "maxHttpHeaderSize": 0,
                "servletPath": "/",
                "jspServlet": null,
                "jetty": { 
                    "maxHttpPostSize": 0,
                    "acceptors": null,
                    "selectors": null
                },
                "connectionTimeout": null
            }
        },
        "spring.metrics.export-org.springframework.boot.actuate.metrics.export.MetricExportProperties": { 
            "prefix": "spring.metrics.export",
            "properties": { 
                "excludes": null,
                "statsd": { 
                    "host": null,
                    "port": 8125,
                    "prefix": null
                },
                "includes": null,
                "enabled": true,
                "redis": { 
                    "prefix": "spring.metrics.application.7a5b013db041f4a1b6c45b6456487d05",
                    "key": "******"
                },
                "aggregate": { 
                    "prefix": "application.7a5b013db041f4a1b6c45b6456487d05",
                    "keyPattern": "k.d"
                }
            }
        },
        "configurationPropertiesReportEndpoint": { 
            "prefix": "endpoints.configprops",
            "properties": { 
                "id": "configprops",
                "sensitive": true,
                "enabled": true
            }
        },
        "healthEndpoint": { 
            "prefix": "endpoints.health",
            "properties": { 
                "timeToLive": 1000,
                "id": "health",
                "sensitive": false,
                "enabled": true
            }
        },
        "loggersMvcEndpoint": { 
            "prefix": "endpoints.loggers",
            "properties": { 
                "path": "/loggers"
            }
        },
        "loggersEndpoint": { 
            "prefix": "endpoints.loggers",
            "properties": { 
                "id": "loggers",
                "sensitive": true,
                "enabled": true
            }
        },
        "endpoints.metrics.filter-org.springframework.boot.actuate.autoconfigure.MetricFilterProperties": { 
            "prefix": "endpoints.metrics.filter",
            "properties": { 
                "counterSubmissions": [
                    "MERGED"
                ],
                "gaugeSubmissions": [
                    "MERGED"
                ]
            }
        },
        "dumpEndpoint": { 
            "prefix": "endpoints.dump",
            "properties": { 
                "id": "dump",
                "sensitive": true,
                "enabled": true
            }
        },
        "autoConfigurationReportEndpoint": { 
            "prefix": "endpoints.autoconfig",
            "properties": { 
                "id": "autoconfig",
                "sensitive": true,
                "enabled": true
            }
        },
        "endpoints.jmx-org.springframework.boot.actuate.autoconfigure.EndpointMBeanExportProperties": { 
            "prefix": "endpoints.jmx",
            "properties": { 
                "uniqueNames": false,
                "enabled": true,
                "domain": ""
            }
        },
        "spring.http.encoding-org.springframework.boot.autoconfigure.web.HttpEncodingProperties": { 
            "prefix": "spring.http.encoding",
            "properties": { 
                "charset": "UTF-8",
                "force": false,
                "mapping": null,
                "forceRequest": false,
                "forceResponse": false
            }
        },
        "shutdownEndpoint": { 
            "prefix": "endpoints.shutdown",
            "properties": { 
                "id": "shutdown",
                "sensitive": true,
                "enabled": false
            }
        },
        "beansEndpoint": { 
            "prefix": "endpoints.beans",
            "properties": { 
                "id": "beans",
                "sensitive": true,
                "enabled": true
            }
        },
        "managementServerProperties": { 
            "prefix": "management",
            "properties": { 
                "security": { 
                    "enabled": false,
                    "roles": [
                        "ACTUATOR"
                    ],
                    "sessions": "STATELESS"
                },
                "address": null,
                "port": null,
                "addApplicationContextHeader": true,
                "contextPath": "",
                "ssl": null
            }
        },
        "requestMappingEndpoint": { 
            "prefix": "endpoints.mappings",
            "properties": { 
                "id": "mappings",
                "sensitive": true,
                "enabled": true
            }
        },
        "endpoints.health-org.springframework.boot.actuate.autoconfigure.HealthMvcEndpointProperties": { 
            "prefix": "endpoints.health",
            "properties": { 
                "mapping": { }
            }
        },
        "spring.mvc-org.springframework.boot.autoconfigure.web.WebMvcProperties": { 
            "prefix": "spring.mvc",
            "properties": { 
                "dateFormat": null,
                "servlet": { 
                    "loadOnStartup": -1
                },
                "staticPathPattern": "/**",
                "dispatchOptionsRequest": true,
                "dispatchTraceRequest": false,
                "locale": null,
                "ignoreDefaultModelOnRedirect": true,
                "logResolvedException": false,
                "async": { 
                    "requestTimeout": null
                },
                "messageCodesResolverFormat": null,
                "mediaTypes": { },
                "view": { 
                    "prefix": null,
                    "suffix": null
                },
                "localeResolver": "ACCEPT_HEADER",
                "throwExceptionIfNoHandlerFound": false
            }
        },
        "diskSpaceHealthIndicatorProperties": { 
            "prefix": "management.health.diskspace",
            "properties": { 
                "path": "/Users/FlySheep/FlySheep/Code/ServerCode/SpringBoot_Demo/demo/.",
                "threshold": 10485760
            }
        }
    }

##### 1.5 生成接口道控制器的映射 #####

在应用程序相对较小的时候，很容易搞清楚控制器都映射到了哪些接口上。如果Web界面的控制器和请求处理方法数量多，那最好能有一个列表，罗列出应用程序发布的全部接口。/mappings 接口就提供了这么一个列表。

{ 
        "/webjars/**": { 
            "bean": "resourceHandlerMapping"
        },
        "/**": { 
            "bean": "resourceHandlerMapping"
        },
        "/**/favicon.ico": { 
            "bean": "faviconHandlerMapping"
        },
        "{[/error]}": { 
            "bean": "requestMappingHandlerMapping",
            "method": "public org.springframework.http.ResponseEntity<java.util.Map<java.lang.String, java.lang.Object>> org.springframework.boot.autoconfigure.web.BasicErrorController.error(javax.servlet.http.HttpServletRequest)"
        },
        "{[/error],produces=[text/html]}": { 
            "bean": "requestMappingHandlerMapping",
            "method": "public org.springframework.web.servlet.ModelAndView org.springframework.boot.autoconfigure.web.BasicErrorController.errorHtml(javax.servlet.http.HttpServletRequest,javax.servlet.http.HttpServletResponse)"
        },
        "{[/env/{name:.*}],methods=[GET],produces=[application/vnd.spring-boot.actuator.v1+json || application/json]}": { 
            "bean": "endpointHandlerMapping",
            "method": "public java.lang.Object org.springframework.boot.actuate.endpoint.mvc.EnvironmentMvcEndpoint.value(java.lang.String)"
        },
        "{[/env || /env.json],methods=[GET],produces=[application/vnd.spring-boot.actuator.v1+json || application/json]}": { 
            "bean": "endpointHandlerMapping",
            "method": "public java.lang.Object org.springframework.boot.actuate.endpoint.mvc.EndpointMvcAdapter.invoke()"
        },
        "{[/beans || /beans.json],methods=[GET],produces=[application/vnd.spring-boot.actuator.v1+json || application/json]}": { 
            "bean": "endpointHandlerMapping",
            "method": "public java.lang.Object org.springframework.boot.actuate.endpoint.mvc.EndpointMvcAdapter.invoke()"
        },
        "{[/auditevents || /auditevents.json],methods=[GET],produces=[application/vnd.spring-boot.actuator.v1+json || application/json]}": { 
            "bean": "endpointHandlerMapping",
            "method": "public org.springframework.http.ResponseEntity<?> org.springframework.boot.actuate.endpoint.mvc.AuditEventsMvcEndpoint.findByPrincipalAndAfterAndType(java.lang.String,java.util.Date,java.lang.String)"
        },
        "{[/autoconfig || /autoconfig.json],methods=[GET],produces=[application/vnd.spring-boot.actuator.v1+json || application/json]}": { 
            "bean": "endpointHandlerMapping",
            "method": "public java.lang.Object org.springframework.boot.actuate.endpoint.mvc.EndpointMvcAdapter.invoke()"
        },
        "{[/loggers/{name:.*}],methods=[GET],produces=[application/vnd.spring-boot.actuator.v1+json || application/json]}": { 
            "bean": "endpointHandlerMapping",
            "method": "public java.lang.Object org.springframework.boot.actuate.endpoint.mvc.LoggersMvcEndpoint.get(java.lang.String)"
        },
        "{[/loggers/{name:.*}],methods=[POST],consumes=[application/vnd.spring-boot.actuator.v1+json || application/json],produces=[application/vnd.spring-boot.actuator.v1+json || application/json]}": { 
            "bean": "endpointHandlerMapping",
            "method": "public java.lang.Object org.springframework.boot.actuate.endpoint.mvc.LoggersMvcEndpoint.set(java.lang.String,java.util.Map<java.lang.String, java.lang.String>)"
        },
        "{[/loggers || /loggers.json],methods=[GET],produces=[application/vnd.spring-boot.actuator.v1+json || application/json]}": { 
            "bean": "endpointHandlerMapping",
            "method": "public java.lang.Object org.springframework.boot.actuate.endpoint.mvc.EndpointMvcAdapter.invoke()"
        },
        "{[/heapdump || /heapdump.json],methods=[GET],produces=[application/octet-stream]}": { 
            "bean": "endpointHandlerMapping",
            "method": "public void org.springframework.boot.actuate.endpoint.mvc.HeapdumpMvcEndpoint.invoke(boolean,javax.servlet.http.HttpServletRequest,javax.servlet.http.HttpServletResponse) throws java.io.IOException,javax.servlet.ServletException"
        },
        "{[/mappings || /mappings.json],methods=[GET],produces=[application/vnd.spring-boot.actuator.v1+json || application/json]}": { 
            "bean": "endpointHandlerMapping",
            "method": "public java.lang.Object org.springframework.boot.actuate.endpoint.mvc.EndpointMvcAdapter.invoke()"
        },
        "{[/trace || /trace.json],methods=[GET],produces=[application/vnd.spring-boot.actuator.v1+json || application/json]}": { 
            "bean": "endpointHandlerMapping",
            "method": "public java.lang.Object org.springframework.boot.actuate.endpoint.mvc.EndpointMvcAdapter.invoke()"
        },
        "{[/configprops || /configprops.json],methods=[GET],produces=[application/vnd.spring-boot.actuator.v1+json || application/json]}": { 
            "bean": "endpointHandlerMapping",
            "method": "public java.lang.Object org.springframework.boot.actuate.endpoint.mvc.EndpointMvcAdapter.invoke()"
        },
        "{[/dump || /dump.json],methods=[GET],produces=[application/vnd.spring-boot.actuator.v1+json || application/json]}": { 
            "bean": "endpointHandlerMapping",
            "method": "public java.lang.Object org.springframework.boot.actuate.endpoint.mvc.EndpointMvcAdapter.invoke()"
        },
        "{[/metrics/{name:.*}],methods=[GET],produces=[application/vnd.spring-boot.actuator.v1+json || application/json]}": { 
            "bean": "endpointHandlerMapping",
            "method": "public java.lang.Object org.springframework.boot.actuate.endpoint.mvc.MetricsMvcEndpoint.value(java.lang.String)"
        },
        "{[/metrics || /metrics.json],methods=[GET],produces=[application/vnd.spring-boot.actuator.v1+json || application/json]}": { 
            "bean": "endpointHandlerMapping",
            "method": "public java.lang.Object org.springframework.boot.actuate.endpoint.mvc.EndpointMvcAdapter.invoke()"
        },
        "{[/health || /health.json],methods=[GET],produces=[application/vnd.spring-boot.actuator.v1+json || application/json]}": { 
            "bean": "endpointHandlerMapping",
            "method": "public java.lang.Object org.springframework.boot.actuate.endpoint.mvc.HealthMvcEndpoint.invoke(javax.servlet.http.HttpServletRequest,java.security.Principal)"
        },
        "{[/info || /info.json],methods=[GET],produces=[application/vnd.spring-boot.actuator.v1+json || application/json]}": { 
            "bean": "endpointHandlerMapping",
            "method": "public java.lang.Object org.springframework.boot.actuate.endpoint.mvc.EndpointMvcAdapter.invoke()"
        }
    }

这里我们可以看到不少接口的映射。每个映射的键都是一个字符串，其内容就是 Spring MVC 的 @RequestMapping 注解上设置的属性。实际上，这个字符串能让你清晰地了解控制器是如何映射的，哪怕不看源代码。每个映射的值都有两个属性：bean 和 method。bean 属性标识了 Spring Bean 的名字，映射源自这个Bean。method属性是映射对应方法的全限定方法签名。

#### 2. 运行时指标 ####

对运行时指标情况做一个快照，这对评估应用程序的健康情况很有帮助。Actuator 提供了一系列接口，让你能在运行时快速检查应用程序。

##### 2.1 查看应用程序的指标值 #####

关于运行中的应用程序，有很多有趣而且有用的信息。举个例子，了解应用程序的内存情况 (可用或空闲)有助于决定给JVM分配多少内存。对Web应用程序而言，不用查看Web服务器日志，如果请求失败或者是耗时太长，就可以大概知道内存的情况了。运行中的应用程序有诸多计数器和度量器，/metrics 接口提供了这些东西的快照。

{ 
        "mem": 365004,
        "mem.free": 153938,
        "processors": 8,
        "instance.uptime": 852279,
        "uptime": 855002,
        "systemload.average": 3.509765625,
        "heap.committed": 316928,
        "heap.init": 262144,
        "heap.used": 162989,
        "heap": 3728384,
        "nonheap.committed": 50816,
        "nonheap.init": 2496,
        "nonheap.used": 48077,
        "nonheap": 0,
        "threads.peak": 18,
        "threads.daemon": 16,
        "threads.totalStarted": 23,
        "threads": 18,
        "classes": 5974,
        "classes.loaded": 5974,
        "classes.unloaded": 0,
        "gc.ps_scavenge.count": 4,
        "gc.ps_scavenge.time": 35,
        "gc.ps_marksweep.count": 1,
        "gc.ps_marksweep.time": 27,
        "httpsessions.max": -1,
        "httpsessions.active": 0,
        "gauge.response.mappings": 4,
        "gauge.response.configprops": 155,
        "counter.status.200.mappings": 1,
        "counter.status.200.configprops": 1
    }

对 /metrics 接口提供的信息进行简单分类如下表：

<table> 
 <thead> 
  <tr> 
   <th>分类</th> 
   <th>前缀</th> 
   <th>报告内容</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td>垃圾收集器</td> 
   <td>gc.*</td> 
   <td>已经发生过的垃圾收集次数，以及垃圾收集所耗费的时间，适用于标记-清理垃圾收集器和并行垃圾收集器(数据源自java.lang.management. GarbageCollectorMXBean)</td> 
  </tr> 
  <tr> 
   <td>内存</td> 
   <td>mem.*</td> 
   <td>分配给应用程序的内存数量和空闲的内存数量(数据源自java.lang. Runtime)</td> 
  </tr> 
  <tr> 
   <td>堆</td> 
   <td>heap.*</td> 
   <td>当前内存用量(数据源自java.lang.management.MemoryUsage)</td> 
  </tr> 
  <tr> 
   <td>类加载器</td> 
   <td>classes.*</td> 
   <td>JVM类加载器加载与卸载的类的数量(数据源自java.lang. management.ClassLoadingMXBean)</td> 
  </tr> 
  <tr> 
   <td>系统</td> 
   <td>processors、instance.uptime、uptime、systemload.average</td> 
   <td>系统信息，例如处理器数量(数据源自java.lang.Runtime)、运行时间(数据源自java.lang.management.RuntimeMXBean)、平均负载(数据源自java.lang.management.OperatingSystemMXBean)</td> 
  </tr> 
  <tr> 
   <td>线程池</td> 
   <td>thread.*</td> 
   <td>线程、守护线程的数量，以及JVM启动后的线程数量峰值(数据源自 java.lang .management.ThreadMXBean)</td> 
  </tr> 
  <tr> 
   <td>数据源</td> 
   <td>datasource.*</td> 
   <td>数据源连接的数量(源自数据源的元数据，仅当Spring应用程序上下文里存在 DataSource Bean 的时候才会有这个信息)</td> 
  </tr> 
  <tr> 
   <td>Tomcat 会话</td> 
   <td>httpsessions.*</td> 
   <td>Tomcat的活跃会话数和最大会话数(数据源自嵌入式Tomcat的Bean，仅在使用嵌入式Tomcat服务器运行应用程序时才有这个信息)</td> 
  </tr> 
  <tr> 
   <td>HTTP</td> 
   <td>counter.status.<em>、gauge.response.</em></td> 
   <td>多种应用程序服务HTTP请求的度量值与计数器</td> 
  </tr> 
 </tbody> 
</table>

请注意，这里的一些度量值，比如数据源和Tomcat会话，仅在应用程序中运行特定组件时才有数据。你还可以注册自己的度量信息。  
　HTTP的计数器和度量值需要做一点说明。counter.status 后的值是HTTP状态码，随后是所请求的路径。举个例子，counter.status.200.metrics 表明/metrics端点返回 200(OK) 状态码的次数。  
　HTTP的度量信息在结构上也差不多，却在报告另一类信息。它们全部以gauge.response 开头,，表明这是HTTP响应的度量信息。前缀后是对应的路径。度量值是以毫秒为单位的时间，反映了最近处理该路径请求的耗时。  
　这里还有几个特殊的值需要注意。root路径指向的是根路径或/。star-star代表了那些Spring 认为是静态资源的路径，包括图片、JavaScript和样式表，其中还包含了那些找不到的资源。这就是为什么你经常会看到 counter.status.404.star-star，这是返回了HTTP 404 (NOT FOUND) 状态的请求数。　　  
　/metrics 接口会返回所有的可用度量值，但你也可能只对某个值感兴趣。要获取单个值，请求时可以在URL后加上对应的键名。例如，要查看空闲内存大小,可以向/metrics/mem.free发一 个GET请求。

##### 2.2 追踪 Web 请求 #####

/trace 接口能报告所有Web请求的详细信息，包括请求方法、路径、时间戳以及请求和响应的头信息。

[
        { 
            "timestamp": 1491279254447,
            "info": { 
                "method": "GET",
                "path": "/metrics",
                "headers": { 
                    "request": { 
                        "host": "localhost:8080",
                        "connection": "keep-alive",
                        "upgrade-insecure-requests": "1",
                        "user-agent": "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_0) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/56.0.2924.87 Safari/537.36",
                        "accept": "text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8",
                        "accept-encoding": "gzip, deflate, sdch, br",
                        "accept-language": "zh-CN,zh;q=0.8,en;q=0.6",
                        "cookie": "JSESSIONID=24CCB83195B2A35F5193C97D2CD51D69"
                    },
                    "response": { 
                        "X-Application-Context": "application",
                        "Content-Type": "application/vnd.spring-boot.actuator.v1+json;charset=UTF-8",
                        "Transfer-Encoding": "chunked",
                        "Date": "Tue, 04 Apr 2017 04:14:14 GMT",
                        "status": "200"
                    }
                }
            }
        }
    ]

##### 2.3 导出线程活动 #####

在确认应用程序运行情况时，除了跟踪请求，了解线程活动也会很有帮助。/dump 接口会生成当前线程活动的快照。

##### 2.4 监控应用程序健康状况 #####

如果你想知道自己的应用程序是否在运行,可以直接访问/health 接口。在最简单的情况下，该端点会显示一个简单的JSON，内容如下:

{ 
        "status": "UP",
        "diskSpace": { 
            "status": "UP",
            "total": 48978722816,
            "free": 8812167168,
            "threshold": 10485760
        }
    }

### 二、定制 Actuator ###

虽然Actuator提供了很多运行中Spring Boot应用程序的内部工作细节，但难免和你的需求有所偏差。也许你并不需要它提供的所有功能，想要关闭一些也说不定。或者，你需要对Actuator 稍作扩展，增加一些自定义的度量信息，以满足你对应用程序的需求。

#### 1. 修改接口 ID ####

每个Actuator 接口都有一个ID用来决定接口的路径，比方说，/beans接口的默认ID就是beans。比如要修改 /beans 为 /instances，则设置如下：

endpoints.beans.id = instances

##### 2. 启用和禁用接口 #####

虽然Actuator的接口都很有用，但你不一定需要全部这些接口。默认情况下，所有接口(除 了/shutdown)都启用。比如要禁用 /metrics 接口，则可以设置如下：

endpoints.metrics.enabled = false

如果你只想打开一两个接口，那就先禁用全部接口，然后启用那几个你要的，这样更方便。

endpoints.enabled = false
    endpoints.metrics.enabled = true

#### 3. 添加自定义度量信息 ####

Actuator 自动配置有两个实例 CounterService 和 GaugeService 可以用来计数使用，我们所要做的就是把它们的实例注入所需的 bean 然后调用相应的方法。除此之外，我们还可以实现 PublicMetrics 接口，提供自己需要的度量信息。

#### 4. 创建自定义跟踪仓库 ####

默认情况下，/trace 接口报告的跟踪信息都存储在内存仓库里，100个条目封顶。一旦仓库满了，就开始移除老的条目，给新的条目腾出空间。在开发阶段这没什么问题，但在生产环境中，大流量会造成跟踪信息还没来得及看就被丢弃。我们可以将那些跟踪条目存储在其他地方——既不消耗内存，又能长久保存的地方。只需实现Spring Boot的TraceRepository接口即可。

#### 5. 插入自定义的健康指示器 ####

实现 HealthIndicator 接口则可以实现自定义的健康指示器。

#### 6. 保护 Actuator 接口 ####

很多Actuator端点发布的信息都可能涉及敏感数据，还有一些端点，(比如/shutdown)非常危险，可以用来关闭应用程序。因此，保护这些端点尤为重要,能访问它们的只能是那些经过授权的客户端。