SpringCloud简介及使用

- 日理万妓 2022-02-04 23:09 260阅读 0赞

# SpringCloud简介 #

Spring cloud是一个基于Spring Boot实现的服务治理工具包，在微服务架构中用于管理和协调服务的  
**微服务：就是把一个单体项目,拆分为多个微服务,每个微服务可以独立技术选型,独立开发,独立部署,独立运维.并且多个服务相互协调,相互配合,最终完成用户的价值.**  
Spring Cloud是一系列框架的有序集合。它利用Spring Boot的开发便利性巧妙地简化了分布式系统基础设施的开发，如服务发现注册、配置中心、消息总线、负载均衡、断路器、数据监控等，都可以用Spring Boot的开发风格做到一键启动和部署  
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**五大重要组件**  
服务发现——Netflix Eureka  
客服端负载均衡——Netflix Ribbon/Feign  
服务网关——Netflix Zuul  
断路器——Netflix Hystrix  
分布式配置——Spring Cloud Config

# Spring cloud入门-搭建环境( 以maven多模块化的方法搭建) #

#### 1.创建Maven普通项目 ####

##### 最外层pom.xml: #####

<properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
        <spring-cloud.version>Finchley.SR1</spring-cloud.version>
        <springboot.version>2.0.5.RELEASE</springboot.version>
    </properties>
    
    <dependencyManagement>
        <dependencies>
    	    <dependency>
    		    <groupId>org.springframework.cloud</groupId>
    		    <artifactId>spring-cloud-dependencies</artifactId>
    		    <version>${spring-cloud.version}</version>
    		    <type>pom</type>
    		    <scope>import</scope>
    	    </dependency>
    	    <dependency>
    		    <groupId>org.springframework.boot</groupId>
    		    <artifactId>spring-boot-dependencies</artifactId>
    		    <version>${springboot.version}</version>
    		    <type>pom</type>
    		    <scope>import</scope>
    	    </dependency>
        </dependencies>
    </dependencyManagement>

#### 2.Spring cloud-Eureka注册中心 ####

Eureka是netflix的一个子模块，也是核心模块之一，Eureka是一个基于REST的服务，用于定位服务，以实现云端中间层服务发现和故障转移  
服务注册与发现对于微服务架构来说是非常重要的，有了服务发现和注册，只需要使用服务的标识符，就可以访问到服务，而不需要修改服务，而不需要修改服务调用的配置文件了

##### 1.创建Maven普通模块User\_eureka\_7001 #####

##### 2.导入jar包 #####

<dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-test</artifactId>
    </dependency>
    
    
    <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-starter-netflix-eureka-server</artifactId>
    </dependency>

##### 3.创建application.yml #####

server:
      port: 7001
    eureka:
      instance:
        hostname: localhost
      client:
          registerWithEureka: false #是否要注册到eureka
          fetchRegistry: false #表示是否从Eureka Server获取注册信息
    serviceUrl:
      defaultZone: http://${eureka.instance.hostname}:${server.port}/eureka/ #单机配置

##### 4.创建启动类 #####

@SpringBootApplication
    @EnableEurekaServer//标识是eureka服务端
    public class EnrekaServerApplication_7001 {
    public static void main(String[] args) {
            SpringApplication.run(EnrekaServerApplication_7001.class);
        }
    }

##### 5.启动入库类访问localhost:7001 #####

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0p1bmVfRmx5aW5nRnJvc3Q_size_16_color_FFFFFF_t_70 1]

#### 3.Spring cloud-服务提供者 ####

##### 1.创建一个模块存放公共代码User\_interface #####

例：  
![在这里插入图片描述][20190503162531579.png]

##### 2.创建服务提供者模块User\_provider\_8001 #####

##### 3.导入jar包和公共模块依赖 #####

<dependencies>
        
        <dependency>
    	    <groupId>cn.itsource.springcloud</groupId>
    	    <artifactId>User_interface</artifactId>
    	    <version>1.0-SNAPSHOT</version>
        </dependency>
        
        
        <dependency>
    	    <groupId>org.springframework.boot</groupId>
    	    <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
    	    <groupId>org.springframework.boot</groupId>
    	    <artifactId>spring-boot-starter-test</artifactId>
        </dependency>
        
        
        <dependency>
    	    <groupId>org.springframework.cloud</groupId>
    	    <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
        </dependency>
    </dependencies>

##### 4.创建application.yml #####

server:
      port: 8001
    spring:
      application:
         name: USER-PROVIDER #不要使用下划线
    eureka:
      client:
        service-url:
          defaultZone: http://localhost:7001/eureka #告诉服务提供者要把服务注册到哪儿
    instance:
        prefer-ip-address: true #显示客户端真实ip

##### 5.创建启动类 #####

@SpringBootApplication
    @EnableEurekaClient //表示是eureka的客户端
    public class UserProviderApplication_8001 {
    public static void main(String[] args) {
            SpringApplication.run(UserProviderApplication_8001.class);
        }
    }

##### 6.创建controller #####

@RestController
    @RequestMapping("/provider")
    public class UserController {
    
    @Autowired
    private IUserService userService;
    
    @RequestMapping("/user/{id}") //user/1
    public User getUser(@PathVariable("id") Long id) {
    
    // 正常应该调用service获取用户,现在模拟一下
    return new User(id, "zs");
        }
    }

#### 4.Spring cloud-服务消费者 ####

##### 1.创建Maven模块项目 User\_consumer\_9001 #####

##### 2.导jar包和公共模块依赖 #####

<dependency>
        <groupId>cn.itsource.springcloud</groupId>
        <artifactId>User_interface</artifactId>
        <version>1.0-SNAPSHOT</version>
    </dependency>
    
    
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-test</artifactId>
    </dependency>

##### 3.创建application.yml #####

server:
      port: 9001
    spring:
      application:
        name: USER_CONSUMER

##### 4.创建启动类 #####

@SpringBootApplication
    public class UserConsumerAppliction_9001 {
    public static void main(String[] args) {
            SpringApplication.run(UserConsumerAppliction_9001.class);
        }
    }

##### 5.创建一个配置bean的类CfgBean #####

@Configuration // <beans></beans>
    public class CfgBean {
    
        @Bean //<bean class="org.springframework.web.client.RestTemplate"></bean>
        public RestTemplate getRestTemplate(){
        return new RestTemplate();
            }
    }

##### 6.创建Controller层 #####

@RestController
    @RequestMapping("/consumer")
    public class UserController {
    
        //多个方法调用只需改一处就ok
        public static  final String URL_PREFIX = "http://localhost:8001";
        
        @Autowired
        private RestTemplate restTemplate;
        
        @RequestMapping("/user/{id}")
        public User getUser(@PathVariable("id")Long id){
    	    //调用远程服务 http请求
    	    String url = URL_PREFIX+"/provider/user/"+id;
    	    return restTemplate.getForObject(url,User.class );
    	}
    }

# Spring cloud入门加强-注册中心集群 #

如果只有一个注册中心服务器，会存在单点故障所以要集群

## 1.搭建集群 ##

##### 1.映射hosts 模拟域名解析 C:\\Windows\\System32\\drivers\\etc #####

127.0.0.1       eureka-7001.com
    127.0.0.1       eureka-7002.com

##### 2.创建User\_eureka\_7002 ，与7001一样 #####

##### 3.配置yml #####

**7001项目的application.yml**

server:
          port: 7001
        eureka:
          instance:
            hostname: eureka-7001.com
          client:
            registerWithEureka: false #是否要注册到eureka
            fetchRegistry: false #表示是否从Eureka Server获取注册信息
            serviceUrl:
              #defaultZone: http://${eureka.instance.hostname}:${server.port}/eureka/ #单机配置
              defaultZone: http://eureka-7002.com:7002/eureka/ #集群配置,如果有多个,有逗号分割,不要包含自己

**7002项目的application.yml**

server:
      port: 7002
    eureka:
      instance:
        hostname: eureka-7002.com
      client:
        registerWithEureka: false #是否要注册到eureka
        fetchRegistry: false #表示是否从Eureka Server获取注册信息
        serviceUrl:
          #defaultZone: http://${eureka.instance.hostname}:${server.port}/eureka/ #单机配置
          defaultZone: http://eureka-7001.com:7001/eureka/ #集群配置,如果有多个,有逗号分割,不要包含自己

##### 4.启动测试 #####

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0p1bmVfRmx5aW5nRnJvc3Q_size_16_color_FFFFFF_t_70 2]![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0p1bmVfRmx5aW5nRnJvc3Q_size_16_color_FFFFFF_t_70 3]

##### 5.服务提供者8001的yml修改 #####

server:
      port: 8001
    spring:
      application:
    name: user-provider #不要使用下划线
    eureka:
      client:
        service-url:
          #defaultZone: http://localhost:7001/eureka #告诉服务提供者要把服务注册到哪儿
          defaultZone: http://eureka-7001.com:7001/eureka,http://eureka-7002.com:7002/eureka
    instance:
      prefer-ip-address: true #显示客户端真实ip

## 2.Spring cloud入门加强-服务消费者（负载均衡） ##

为了提供并发量，有时同一个服务提供者可以部署多个。这个客户端在调用时要根据一定的负责均衡策略完成负载调用

### Spring cloud中常见负载均衡实现技术 ###

#### 1.Ribbon负载均衡 ####

Ribbon是Netflix发布的云中间层服务开源项目，主要功能是提供客户端负载均衡算法。Ribbon客户端组件提供一系列完善的配置项，如，连接超时，重试等

##### 1.创建项目 User\_provider\_8002,并注册到注册中心 #####

##### 2.User\_consumer\_9001导入ribbon的jar包 #####

<dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-starter-ribbon</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-starter-config</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
    </dependency>

##### 3.修改User\_consumer\_9001的yml #####

server:
      port: 9001
    eureka:
      client:
        registerWithEureka: false #不注册到Eureka,不在注册中心显示
        service-url:
          #defaultZone: http://localhost:7001/eureka
          defaultZone: http://eureka-7001.com:7001/eureka,http://eureka-7002.com:7002/eureka

##### 4.启动类 #####

@SpringBootApplication
    @EnableEurekaClient
    public class UserConsumerApplicaton_9001 {
    public static void main(String[] args) {
            SpringApplication.run(UserConsumerApplicaton_9001.class);
        }
    }

##### 5.修改User\_consumer\_9001的config包的CfgBean类 #####

@Configuration
    public class CfgBean {
    
    @Bean
     @LoadBalanced //开启负载均衡
    public RestTemplate getRestTemplate(){
    return  new RestTemplate();
        }
    }

##### 6.修改Controller #####

@RestController
    @RequestMapping("/consumer")
    public class UserController {
    
    //多个方法调用只需改一处就ok
        //public static  final String URL_PREFIX = "http://localhost:8001";
    public static  final String URL_PREFIX ="http://USER-PROVIDER"; //通过服务名从注册中心获取服务列表,通过负载均衡调用
    
    @Autowired
    private RestTemplate restTemplate;
    
    @RequestMapping("/user/{id}")
    public User getUser(@PathVariable("id")Long id){
    //调用远程服务 http请求
    String url = URL_PREFIX+"/provider/user/"+id;
    return restTemplate.getForObject(url,User.class );
        }
    }

#### 2.Feign负载均衡 ####

前面的可以发现当我们通过RestTemplate调用其它服务的API时，所需要的参数须在请求的URL中进行拼接，如果参数少的话或许我们还可以忍受，一旦有多个参数的话，这时拼接请求字符串就会效率低下，并且显得好傻  
![在这里插入图片描述][2019050318411254.png]  
Feign是以接口方式进行调用,而不是通过RestTemplate来调用,feign底层还是ribbo,它进行了封装,

##### 1.创建 User\_consum\_9002模块 #####

##### 2.到jar包 #####

<dependencies>
        
        <dependency>
    	    <groupId>cn.itsource.springcloud</groupId>
    	    <artifactId>User_interface</artifactId>
    	    <version>1.0-SNAPSHOT</version>
        </dependency>
        
        
        <dependency>
    	    <groupId>org.springframework.boot</groupId>
    	    <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
    	    <groupId>org.springframework.boot</groupId>
    	    <artifactId>spring-boot-starter-test</artifactId>
        </dependency>
        
        
        <dependency>
    	    <groupId>org.springframework.cloud</groupId>
    	    <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
        </dependency>
        
        
        <dependency>
    	    <groupId>org.springframework.cloud</groupId>
    	    <artifactId>spring-cloud-starter-openfeign</artifactId>
        </dependency>
    </dependencies>

##### 3.创建application.yml #####

server:
      port: 9002
    eureka:
      client:
        registerWithEureka: false #不注册到Eureka,不在注册中心显示
        service-url:
          #defaultZone: http://localhost:7001/eureka
          defaultZone: http://eureka-7001.com:7001/eureka,http://eureka-7002.com:7002/eureka

##### 4.创建启动类 #####

@SpringBootApplication
    @EnableEurekaClient
    @EnableFeignClients(basePackages = "cn.itsource.microservice") //不在当前包下面
    public class UserConsumerFeign9002Application {
    
    	public static void main(String[] args) {
    		SpringApplication.run(UserConsumerFeign9002Application.class, args);
    	}
    }

##### 5.创建一个接口来调用服务 #####

//调用服务名字
    @FeignClient(value = "USER-PROVIDER")
    public interface UserCilent {
        @RequestMapping("/provider/user/{id}") //user/1
        User getUser(@PathVariable("id") Long id);
    }

##### 6.Controller层 #####

@RestController
    @RequestMapping("/consumer")
    public class UserController {
    
        @Autowired
        private UserCilent userCilent;
        
        @RequestMapping("/user/{id}")
        public User getUser(@PathVariable("id")Long id){
                System.out.println(userCilent.getClass());
        		return userCilent.getUser(id);
        }
    }

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