jdb 调试

短命女 2022-11-20 06:58 121阅读 0赞

**目录**

1、代码

2、编译代码

3、调试

3.1 jdb

3.2 stop

3.3 list

3.4 run

3.5 list

3.6 step

3.7 print dump eval

3.8 set

3.9 locals

3.10 next

3.11 cont

3.12 n 命令

3.13 help

3.14 !!

3.15 version

4、spring boot调试

4.1 代码

4.2 启动脚本

4.3 连接debug端口

4.3.1 连接

4.3.2 打断点

4.3.3 访问接口

4.3.4 调试

--------------------

# 1、代码 #

/**
     * @ClassName Num
     * @Description:
     * @Author ybwei
     * @Date 2020/10/30
     * @Version V1.0
     **/
    public class Num {
    
        public static int add(int a,int b){
            return a+b;
        }
    
        public static void main(String[] args) {
            int a=3;
            int b=5;
            int c=a+b;
            System.out.println(c);
        }
    }

## 2、编译代码 ##

>javac -g Num.java

**-g**

生成所有的调试信息，包括[局部变量][Link 1]。缺省情况下，只生成行号和源文件信息。

通过这个参数，可以在生成的class文件中，添加具体的 line,source,vars 信息，具体的作用体现在：

1.  因为调试的时候需要符号信息，所以一定需要这个参数
2.  在抛出Exception的时候，可以知道具体的错误位置，而非Unknown Source。

添加了这个参数后，不可避免的class文件会变大一点，但是为了以后的维护，还是非常值得的。

# 3、调试 #

## 3.1 jdb ##

Num.class添加到JDB进行调试。

[root@iZ2ze8o82mhgjvdsmrwz8bZ test]# jdb Num
    Initializing jdb ...

## 3.2 stop ##

加载成功后，我们通常会在 main函数的位置加上断点

> stop in Num.main
    Deferring breakpoint Num.main.
    It will be set after the class is loaded.

## 3.3 list ##

查看被成功加入的断点

> clear
    Breakpoints set:
    	breakpoint Num.main

## 3.4 run ##

运行程序，程序暂停到main函数的第一行

> run
    run Num
    Set uncaught java.lang.Throwable
    Set deferred uncaught java.lang.Throwable
    > 
    VM Started: Set deferred breakpoint Num.main
    
    Breakpoint hit: "thread=main", Num.main(), line=15 bci=0
    15            int a=3;
    
    main[1]

## 3.5 list ##

查看源代码，=>当前正在执行的行

main[1] list
    11            return a+b;
    12        }
    13    
    14        public static void main(String[] args) {
    15 =>         int a=3;
    16            int b=5;
    17            int c=a+b;
    18            System.out.println(c);
    19        }
    20    }

## 3.6 step ##

下一步

main[1] step
    
    Step completed: "thread=main", Num.main(), line=16 bci=2
    16            int b=5;

## 3.7 print dump eval  ##

main[1] main[1] print a
     a = 3
    main[1] dump a
     a = 3
    main[1] eval a
     a = 3

## 3.8 set ##

修改变量

main[1] set a=1
     a=1 = 1
    main[1] print a
     a = 1

## 3.9 locals ##

显示当前堆栈帧中的所有本地变量

main[1] locals
    Method arguments:
    args = instance of java.lang.String[0] (id=385)
    Local variables:
    a = 1

## 3.10 next ##

下一步

main[1] next
    > 
    Step completed: "thread=main", Num.main(), line=17 bci=4
    17            int c=a+b;

next和step的区别

在执行有方法调用的语句时，next会把方法执行完，step会进入方法体。所以在调试时，单步执行我们要优先使用next，这样效率比较高。

## 3.11 cont ##

从当前位置直接执行到程序结束（或者下一个断点或信号）

main[1] cont
    6
    > 
    The application exited
    [root@iZ2ze8o82mhgjvdsmrwz8bZ test]#

## 3.12 n 命令 ##

将某个命令重复执行n次

[root@iZ2ze8o82mhgjvdsmrwz8bZ test]# jdb Num
    Initializing jdb ...
    > stop in Num.main
    Deferring breakpoint Num.main.
    It will be set after the class is loaded.
    > run
    run Num
    Set uncaught java.lang.Throwable
    Set deferred uncaught java.lang.Throwable
    > 
    VM Started: Set deferred breakpoint Num.main
    
    Breakpoint hit: "thread=main", Num.main(), line=15 bci=0
    15            int a=3;
    
    main[1] 2 step
    
    Step completed: "thread=main", Num.main(), line=16 bci=2
    16            int b=5;
    
    main[1] main[1] 
    Step completed: "thread=main", Num.main(), line=17 bci=4
    17            int c=a+b;

## 3.13 help ##

main[1] main[1] help 
    ** command list **
    connectors                -- list available connectors and transports in this VM
    
    run [class [args]]        -- start execution of application's main class
    
    threads [threadgroup]     -- list threads
    thread <thread id>        -- set default thread
    suspend [thread id(s)]    -- suspend threads (default: all)
    resume [thread id(s)]     -- resume threads (default: all)
    where [<thread id> | all] -- dump a thread's stack
    wherei [<thread id> | all]-- dump a thread's stack, with pc info
    up [n frames]             -- move up a thread's stack
    down [n frames]           -- move down a thread's stack
    kill <thread id> <expr>   -- kill a thread with the given exception object
    interrupt <thread id>     -- interrupt a thread
    
    print <expr>              -- print value of expression
    dump <expr>               -- print all object information
    eval <expr>               -- evaluate expression (same as print)
    set <lvalue> = <expr>     -- assign new value to field/variable/array element
    locals                    -- print all local variables in current stack frame
    
    classes                   -- list currently known classes
    class <class id>          -- show details of named class
    methods <class id>        -- list a class's methods
    fields <class id>         -- list a class's fields
    
    threadgroups              -- list threadgroups
    threadgroup <name>        -- set current threadgroup
    
    stop in <class id>.<method>[(argument_type,...)]
                              -- set a breakpoint in a method
    stop at <class id>:<line> -- set a breakpoint at a line
    clear <class id>.<method>[(argument_type,...)]
                              -- clear a breakpoint in a method
    clear <class id>:<line>   -- clear a breakpoint at a line
    clear                     -- list breakpoints
    catch [uncaught|caught|all] <class id>|<class pattern>
                              -- break when specified exception occurs
    ignore [uncaught|caught|all] <class id>|<class pattern>
                              -- cancel 'catch' for the specified exception
    watch [access|all] <class id>.<field name>
                              -- watch access/modifications to a field
    unwatch [access|all] <class id>.<field name>
                              -- discontinue watching access/modifications to a field
    trace [go] methods [thread]
                              -- trace method entries and exits.
                              -- All threads are suspended unless 'go' is specified
    trace [go] method exit | exits [thread]
                              -- trace the current method's exit, or all methods' exits
                              -- All threads are suspended unless 'go' is specified
    untrace [methods]         -- stop tracing method entrys and/or exits
    step                      -- execute current line
    step up                   -- execute until the current method returns to its caller
    stepi                     -- execute current instruction
    next                      -- step one line (step OVER calls)
    cont                      -- continue execution from breakpoint
    
    list [line number|method] -- print source code
    use (or sourcepath) [source file path]
                              -- display or change the source path
    exclude [<class pattern>, ... | "none"]
                              -- do not report step or method events for specified classes
    classpath                 -- print classpath info from target VM
    
    monitor <command>         -- execute command each time the program stops
    monitor                   -- list monitors
    unmonitor <monitor#>      -- delete a monitor
    read <filename>           -- read and execute a command file
    
    lock <expr>               -- print lock info for an object
    threadlocks [thread id]   -- print lock info for a thread
    
    pop                       -- pop the stack through and including the current frame
    reenter                   -- same as pop, but current frame is reentered
    redefine <class id> <class file name>
                              -- redefine the code for a class
    
    disablegc <expr>          -- prevent garbage collection of an object
    enablegc <expr>           -- permit garbage collection of an object
    
    !!                        -- repeat last command
    <n> <command>             -- repeat command n times
    # <command>               -- discard (no-op)
    help (or ?)               -- list commands
    version                   -- print version information
    exit (or quit)            -- exit debugger
    
    <class id>: a full class name with package qualifiers
    <class pattern>: a class name with a leading or trailing wildcard ('*')
    <thread id>: thread number as reported in the 'threads' command
    <expr>: a Java(TM) Programming Language expression.
    Most common syntax is supported.
    
    Startup commands can be placed in either "jdb.ini" or ".jdbrc"
    in user.home or user.dir

## 3.14 !! ##

重复执行上一命令，如下重新执行step

main[1] step
    > 
    Step completed: "thread=main", Num.main(), line=18 bci=8
    18            System.out.println(c);
    
    main[1] !!
    step
    8
    > 
    Step completed: "thread=main", Num.main(), line=19 bci=15
    19        }

## 3.15 version ##

jdb版本号

# 4、spring boot调试 #

## 4.1 代码 ##

代码参考[https://blog.csdn.net/xixingzhe2/article/details/109311203][https_blog.csdn.net_xixingzhe2_article_details_109311203]

## 4.2 启动脚本 ##

编辑、启动脚本

[root remote]# vim start-jdb.sh 
    
    java -agentlib:jdwp=transport=dt_socket,server=y,suspend=n,address=5005 -jar remote.debug-1.0.jar
    [root remote]# ./start-jdb.sh 
    Listening for transport dt_socket at address: 5005
    15:45:05,473 |-INFO in ch.qos.logback.classic.LoggerContext[default] - Could NOT find resource [logback-test.xml]
    15:45:05,473 |-INFO in ch.qos.logback.classic.LoggerContext[default] - Could NOT find resource [logback.groovy]
    15:45:05,474 |-INFO in ch.qos.logback.classic.LoggerContext[default] - Found resource [logback.xml] at [jar:file:/root/remote/remote.debug-1.0.jar!/BOOT-INF/classes!/logback.xml]
    15:45:05,517 |-INFO in ch.qos.logback.core.joran.spi.ConfigurationWatchList@130f889 - URL [jar:file:/root/remote/remote.debug-1.0.jar!/BOOT-INF/classes!/logback.xml] is not of type file
    15:45:05,609 |-INFO in ch.qos.logback.classic.joran.action.ConfigurationAction - debug attribute not set
    15:45:05,611 |-INFO in ch.qos.logback.core.joran.action.AppenderAction - About to instantiate appender of type [ch.qos.logback.core.ConsoleAppender]
    15:45:05,631 |-INFO in ch.qos.logback.core.joran.action.AppenderAction - Naming appender as [stdout]
    15:45:05,644 |-INFO in ch.qos.logback.core.joran.action.NestedComplexPropertyIA - Assuming default type [ch.qos.logback.classic.encoder.PatternLayoutEncoder] for [encoder] property
    15:45:05,732 |-INFO in ch.qos.logback.core.joran.action.AppenderAction - About to instantiate appender of type [ch.qos.logback.core.rolling.RollingFileAppender]
    15:45:05,738 |-INFO in ch.qos.logback.core.joran.action.AppenderAction - Naming appender as [InfoFile]
    15:45:05,763 |-INFO in c.q.l.core.rolling.TimeBasedRollingPolicy@294184992 - No compression will be used
    15:45:05,765 |-INFO in c.q.l.core.rolling.TimeBasedRollingPolicy@294184992 - Will use the pattern d:/logs/info/info-%d{yyyy-MM-dd}.%i.log for the active file
    15:45:05,769 |-INFO in ch.qos.logback.core.rolling.SizeAndTimeBasedFNATP@2f490758 - The date pattern is 'yyyy-MM-dd' from file name pattern 'd:/logs/info/info-%d{yyyy-MM-dd}.%i.log'.
    15:45:05,769 |-INFO in ch.qos.logback.core.rolling.SizeAndTimeBasedFNATP@2f490758 - Roll-over at midnight.
    15:45:05,772 |-INFO in ch.qos.logback.core.rolling.SizeAndTimeBasedFNATP@2f490758 - Setting initial period to Fri Oct 30 15:42:11 CST 2020
    15:45:05,772 |-WARN in ch.qos.logback.core.rolling.SizeAndTimeBasedFNATP@2f490758 - SizeAndTimeBasedFNATP is deprecated. Use SizeAndTimeBasedRollingPolicy instead
    15:45:05,772 |-WARN in ch.qos.logback.core.rolling.SizeAndTimeBasedFNATP@2f490758 - For more information see http://logback.qos.ch/manual/appenders.html#SizeAndTimeBasedRollingPolicy
    15:45:05,776 |-WARN in ch.qos.logback.core.rolling.RollingFileAppender[InfoFile] - This appender no longer admits a layout as a sub-component, set an encoder instead.
    15:45:05,776 |-WARN in ch.qos.logback.core.rolling.RollingFileAppender[InfoFile] - To ensure compatibility, wrapping your layout in LayoutWrappingEncoder.
    15:45:05,776 |-WARN in ch.qos.logback.core.rolling.RollingFileAppender[InfoFile] - See also http://logback.qos.ch/codes.html#layoutInsteadOfEncoder for details
    15:45:05,781 |-INFO in ch.qos.logback.core.rolling.RollingFileAppender[InfoFile] - Active log file name: d:/logs/info/info.log
    15:45:05,781 |-INFO in ch.qos.logback.core.rolling.RollingFileAppender[InfoFile] - File property is set to [d:/logs/info/info.log]
    15:45:05,782 |-INFO in ch.qos.logback.core.joran.action.AppenderAction - About to instantiate appender of type [ch.qos.logback.core.rolling.RollingFileAppender]
    15:45:05,783 |-INFO in ch.qos.logback.core.joran.action.AppenderAction - Naming appender as [ErrorFile]
    15:45:05,786 |-INFO in c.q.l.core.rolling.TimeBasedRollingPolicy@270397815 - No compression will be used
    15:45:05,786 |-INFO in c.q.l.core.rolling.TimeBasedRollingPolicy@270397815 - Will use the pattern d:/logs/error/error-%d{yyyy-MM-dd}.%i.log for the active file
    15:45:05,786 |-INFO in ch.qos.logback.core.rolling.SizeAndTimeBasedFNATP@166fa74d - The date pattern is 'yyyy-MM-dd' from file name pattern 'd:/logs/error/error-%d{yyyy-MM-dd}.%i.log'.
    15:45:05,786 |-INFO in ch.qos.logback.core.rolling.SizeAndTimeBasedFNATP@166fa74d - Roll-over at midnight.
    15:45:05,787 |-INFO in ch.qos.logback.core.rolling.SizeAndTimeBasedFNATP@166fa74d - Setting initial period to Tue Oct 27 14:51:05 CST 2020
    15:45:05,787 |-WARN in ch.qos.logback.core.rolling.SizeAndTimeBasedFNATP@166fa74d - SizeAndTimeBasedFNATP is deprecated. Use SizeAndTimeBasedRollingPolicy instead
    15:45:05,787 |-WARN in ch.qos.logback.core.rolling.SizeAndTimeBasedFNATP@166fa74d - For more information see http://logback.qos.ch/manual/appenders.html#SizeAndTimeBasedRollingPolicy
    15:45:05,788 |-WARN in ch.qos.logback.core.rolling.RollingFileAppender[ErrorFile] - This appender no longer admits a layout as a sub-component, set an encoder instead.
    15:45:05,788 |-WARN in ch.qos.logback.core.rolling.RollingFileAppender[ErrorFile] - To ensure compatibility, wrapping your layout in LayoutWrappingEncoder.
    15:45:05,788 |-WARN in ch.qos.logback.core.rolling.RollingFileAppender[ErrorFile] - See also http://logback.qos.ch/codes.html#layoutInsteadOfEncoder for details
    15:45:05,789 |-INFO in ch.qos.logback.core.rolling.RollingFileAppender[ErrorFile] - Active log file name: d:/logs/error/error.log
    15:45:05,789 |-INFO in ch.qos.logback.core.rolling.RollingFileAppender[ErrorFile] - File property is set to [d:/logs/error/error.log]
    15:45:05,789 |-INFO in ch.qos.logback.core.joran.action.AppenderAction - About to instantiate appender of type [ch.qos.logback.core.rolling.RollingFileAppender]
    15:45:05,789 |-INFO in ch.qos.logback.core.joran.action.AppenderAction - Naming appender as [AllFile]
    15:45:05,790 |-INFO in c.q.l.core.rolling.TimeBasedRollingPolicy@1089504328 - No compression will be used
    15:45:05,790 |-INFO in c.q.l.core.rolling.TimeBasedRollingPolicy@1089504328 - Will use the pattern d:/logs/all/all-%d{yyyy-MM-dd}.%i.log for the active file
    15:45:05,791 |-INFO in ch.qos.logback.core.rolling.SizeAndTimeBasedFNATP@276438c9 - The date pattern is 'yyyy-MM-dd' from file name pattern 'd:/logs/all/all-%d{yyyy-MM-dd}.%i.log'.
    15:45:05,791 |-INFO in ch.qos.logback.core.rolling.SizeAndTimeBasedFNATP@276438c9 - Roll-over at midnight.
    15:45:05,791 |-INFO in ch.qos.logback.core.rolling.SizeAndTimeBasedFNATP@276438c9 - Setting initial period to Fri Oct 30 15:42:11 CST 2020
    15:45:05,791 |-WARN in ch.qos.logback.core.rolling.SizeAndTimeBasedFNATP@276438c9 - SizeAndTimeBasedFNATP is deprecated. Use SizeAndTimeBasedRollingPolicy instead
    15:45:05,791 |-WARN in ch.qos.logback.core.rolling.SizeAndTimeBasedFNATP@276438c9 - For more information see http://logback.qos.ch/manual/appenders.html#SizeAndTimeBasedRollingPolicy
    15:45:05,792 |-WARN in ch.qos.logback.core.rolling.RollingFileAppender[AllFile] - This appender no longer admits a layout as a sub-component, set an encoder instead.
    15:45:05,792 |-WARN in ch.qos.logback.core.rolling.RollingFileAppender[AllFile] - To ensure compatibility, wrapping your layout in LayoutWrappingEncoder.
    15:45:05,792 |-WARN in ch.qos.logback.core.rolling.RollingFileAppender[AllFile] - See also http://logback.qos.ch/codes.html#layoutInsteadOfEncoder for details
    15:45:05,792 |-INFO in ch.qos.logback.core.rolling.RollingFileAppender[AllFile] - Active log file name: d:/logs/all/all.log
    15:45:05,792 |-INFO in ch.qos.logback.core.rolling.RollingFileAppender[AllFile] - File property is set to [d:/logs/all/all.log]
    15:45:05,794 |-INFO in ch.qos.logback.classic.joran.action.LoggerAction - Setting level of logger [org.mybatis] to TRACE
    15:45:05,794 |-INFO in ch.qos.logback.classic.joran.action.LoggerAction - Setting level of logger [com.cloud.mapper] to DEBUG
    15:45:05,794 |-INFO in ch.qos.logback.classic.joran.action.RootLoggerAction - Setting level of ROOT logger to INFO
    15:45:05,794 |-INFO in ch.qos.logback.core.joran.action.AppenderRefAction - Attaching appender named [stdout] to Logger[ROOT]
    15:45:05,795 |-INFO in ch.qos.logback.core.joran.action.AppenderRefAction - Attaching appender named [InfoFile] to Logger[ROOT]
    15:45:05,795 |-INFO in ch.qos.logback.core.joran.action.AppenderRefAction - Attaching appender named [ErrorFile] to Logger[ROOT]
    15:45:05,795 |-INFO in ch.qos.logback.core.joran.action.AppenderRefAction - Attaching appender named [AllFile] to Logger[ROOT]
    15:45:05,795 |-INFO in ch.qos.logback.classic.joran.action.ConfigurationAction - End of configuration.
    15:45:05,800 |-INFO in ch.qos.logback.classic.joran.JoranConfigurator@588df31b - Registering current configuration as safe fallback point
    
    
      .   ____          _            __ _ _
     /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
    ( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
     \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
      '  |____| .__|_| |_|_| |_\__, | / / / /
     =========|_|==============|___/=/_/_/_/
     :: Spring Boot ::        (v2.1.7.RELEASE)
    
    [INFO ] 2020-10-30 15:45:06.651 [main] com.cloud.ProviderApplication - Starting ProviderApplication v1.0 on iZbp18ily7toc0qsr1pbb6Z with PID 1897 (/root/remote/remote.debug-1.0.jar started by root in /root/remote)
    [INFO ] 2020-10-30 15:45:06.688 [main] com.cloud.ProviderApplication - No active profile set, falling back to default profiles: default
    [INFO ] 2020-10-30 15:45:08.408 [main] o.s.b.w.e.tomcat.TomcatWebServer - Tomcat initialized with port(s): 8080 (http)
    [INFO ] 2020-10-30 15:45:08.435 [main] o.a.coyote.http11.Http11NioProtocol - Initializing ProtocolHandler ["http-nio-8080"]
    [INFO ] 2020-10-30 15:45:08.465 [main] o.a.catalina.core.StandardService - Starting service [Tomcat]
    [INFO ] 2020-10-30 15:45:08.465 [main] o.a.catalina.core.StandardEngine - Starting Servlet engine: [Apache Tomcat/9.0.22]
    [INFO ] 2020-10-30 15:45:08.592 [main] o.a.c.c.C.[Tomcat].[localhost].[/] - Initializing Spring embedded WebApplicationContext
    [INFO ] 2020-10-30 15:45:08.593 [main] o.s.web.context.ContextLoader - Root WebApplicationContext: initialization completed in 1800 ms
    [INFO ] 2020-10-30 15:45:09.097 [main] o.s.s.c.ThreadPoolTaskExecutor - Initializing ExecutorService 'applicationTaskExecutor'
    [INFO ] 2020-10-30 15:45:09.355 [main] o.a.coyote.http11.Http11NioProtocol - Starting ProtocolHandler ["http-nio-8080"]
    [INFO ] 2020-10-30 15:45:09.381 [main] o.s.b.w.e.tomcat.TomcatWebServer - Tomcat started on port(s): 8080 (http) with context path ''
    [INFO ] 2020-10-30 15:45:09.391 [main] com.cloud.ProviderApplication - Started ProviderApplication in 3.436 seconds (JVM running for 4.265)

## 4.3 连接debug端口 ##

### 4.3.1 连接 ###

[root@iZbp18ily7toc0qsr1pbb6Z ~]# jdb -connect com.sun.jdi.SocketAttach:hostname=127.0.0.1,port=5005
    Set uncaught java.lang.Throwable
    Set deferred uncaught java.lang.Throwable
    Initializing jdb ...
    >

## 4.3.2 打断点 ##

> stop in com.cloud.controller.TestController.getUser
    Set breakpoint com.cloud.controller.TestController.getUser

### 4.3.3 访问接口 ###

[http://IP:8080/getUser?id=2][http_IP_8080_getUser_id_2]

### 4.3.4 调试 ###

> 
    Breakpoint hit: "thread=http-nio-8080-exec-1", com.cloud.controller.TestController.getUser(), line=40 bci=0
    
    http-nio-8080-exec-1[1] step
    > 
    Step completed: "thread=http-nio-8080-exec-1", com.cloud.service.impl.UserServiceImpl.getUser(), line=21 bci=0
    
    http-nio-8080-exec-1[1] print id
     id = "2"
    http-nio-8080-exec-1[1]

[Link 1]: https://baike.baidu.com/item/%E5%B1%80%E9%83%A8%E5%8F%98%E9%87%8F
[https_blog.csdn.net_xixingzhe2_article_details_109311203]: https://blog.csdn.net/xixingzhe2/article/details/109311203
[http_IP_8080_getUser_id_2]: http://47.96.252.183:8080/getUser?id=2