github地址:

Arthas

English version goes here.

Arthas 是Alibaba开源的Java诊断工具，深受开发者喜爱。

当你遇到以下类似问题而束手无策时，Arthas可以帮助你解决：

1. 这个类从哪个 jar 包加载的？为什么会报各种类相关的 Exception？
2. 我改的代码为什么没有执行到？难道是我没 commit？分支搞错了？
3. 遇到问题无法在线上 debug，难道只能通过加日志再重新发布吗？
4. 线上遇到某个用户的数据处理有问题，但线上同样无法 debug，线下无法重现！
5. 是否有一个全局视角来查看系统的运行状况？
6. 有什么办法可以监控到JVM的实时运行状态？

Arthas采用命令行交互模式，同时提供丰富的 Tab 自动补全功能，进一步方便进行问题的定位和诊断。

快速开始

Linux/Unix/Mac

安装Arthas:

curl -L https://alibaba.github.io/arthas/install.sh | sh

启动Arthas:

./as.sh

Windows

1. 点击 这里 下载最新的Arthas zip包
2. 解压缩zip包.
3. 进入bin目录
4. 执行以下命令 as.bat $PID

文档

社区正在进行英文版本的翻译工作，如果您有兴趣请在 这里留言。

• 用户文档
• 安装
• 快速入门
• 进阶使用
• Questions and answers
• 参与贡献

案例展示

Dashboard

• https://alibaba.github.io/arthas/dashboard

Thread

一目了然的了解系统的状态，哪些线程比较占cpu？他们到底在做什么？

1. $ thread -n 3

2. "as-command-execute-daemon" Id=29 cpuUsage=75% RUNNABLE

3. at sun.management.ThreadImpl.dumpThreads0(Native Method)

4. at sun.management.ThreadImpl.getThreadInfo(ThreadImpl.java:440)

5. at com.taobao.arthas.core.command.monitor200.ThreadCommand$1.action(ThreadCommand.java:58)

6. at com.taobao.arthas.core.command.handler.AbstractCommandHandler.execute(AbstractCommandHandler.java:238)

7. at com.taobao.arthas.core.command.handler.DefaultCommandHandler.handleCommand(DefaultCommandHandler.java:67)

8. at com.taobao.arthas.core.server.ArthasServer$4.run(ArthasServer.java:276)

9. at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)

10. at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)

11. at java.lang.Thread.run(Thread.java:745)

12.  

13. Number of locked synchronizers = 1

14. - java.util.concurrent.ThreadPoolExecutor$Worker@6cd0b6f8

15.  

16. "as-session-expire-daemon" Id=25 cpuUsage=24% TIMED_WAITING

17. at java.lang.Thread.sleep(Native Method)

18. at com.taobao.arthas.core.server.DefaultSessionManager$2.run(DefaultSessionManager.java:85)

19.  

20. "Reference Handler" Id=2 cpuUsage=0% WAITING on java.lang.ref.Reference$Lock@69ba0f27

21. at java.lang.Object.wait(Native Method)

22. - waiting on java.lang.ref.Reference$Lock@69ba0f27

23. at java.lang.Object.wait(Object.java:503)

24. at java.lang.ref.Reference$ReferenceHandler.run(Reference.java:133)

jad

对类进行反编译:

$ jad javax.servlet.Servlet

ClassLoader:
+-java.net.URLClassLoader@6108b2d7
  +-sun.misc.Launcher$AppClassLoader@18b4aac2
    +-sun.misc.Launcher$ExtClassLoader@1ddf84b8

Location:
/Users/xxx/work/test/lib/servlet-api.jar

/*
 * Decompiled with CFR 0_122.
 */
package javax.servlet;

import java.io.IOException;
import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;

public interface Servlet {
    public void init(ServletConfig var1) throws ServletException;

    public ServletConfig getServletConfig();

    public void service(ServletRequest var1, ServletResponse var2) throws ServletException, IOException;

    public String getServletInfo();

    public void destroy();
}

sc

查找JVM中已经加载的类

1. $ sc -d org.springframework.web.context.support.XmlWebApplicationContext

2. class-info org.springframework.web.context.support.XmlWebApplicationContext

3. code-source /Users/xxx/work/test/WEB-INF/lib/spring-web-3.2.11.RELEASE.jar

4. name org.springframework.web.context.support.XmlWebApplicationContext

5. isInterface false

6. isAnnotation false

7. isEnum false

8. isAnonymousClass false

9. isArray false

10. isLocalClass false

11. isMemberClass false

12. isPrimitive false

13. isSynthetic false

14. simple-name XmlWebApplicationContext

15. modifier public

16. annotation

17. interfaces

18. super-class +-org.springframework.web.context.support.AbstractRefreshableWebApplicationContext

19. +-org.springframework.context.support.AbstractRefreshableConfigApplicationContext

20. +-org.springframework.context.support.AbstractRefreshableApplicationContext

21. +-org.springframework.context.support.AbstractApplicationContext

22. +-org.springframework.core.io.DefaultResourceLoader

23. +-java.lang.Object

24. class-loader +-org.apache.catalina.loader.ParallelWebappClassLoader

25. +-java.net.URLClassLoader@6108b2d7

26. +-sun.misc.Launcher$AppClassLoader@18b4aac2

27. +-sun.misc.Launcher$ExtClassLoader@1ddf84b8

28. classLoaderHash 25131501

29.  

stack

查看方法 test.arthas.TestStack#doGet 的调用堆栈：

1. $ stack test.arthas.TestStack doGet

2. Press Ctrl+C to abort.

3. Affect(class-cnt:1 , method-cnt:1) cost in 286 ms.

4. ts=2018-09-18 10:11:45;thread_name=http-bio-8080-exec-10;id=d9;is_daemon=true;priority=5;TCCL=org.apache.catalina.loader.ParallelWebappClassLoader@25131501

5. @test.arthas.TestStack.doGet()

6. at javax.servlet.http.HttpServlet.service(HttpServlet.java:624)

7. at javax.servlet.http.HttpServlet.service(HttpServlet.java:731)

8. at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)

9. at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)

10. at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)

11. at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)

12. at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)

13. at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)

14. at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)

15. at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220)

16. at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:110)

17. ...

18. at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:169)

19. at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)

20. at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)

21. at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:451)

22. at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1121)

23. at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:637)

24. at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:316)

25. at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)

26. at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)

27. at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)

28. at java.lang.Thread.run(Thread.java:745)

Trace

观察方法执行的时候那个子调用比较慢:

Watch

观察方法 test.arthas.TestWatch#doGet 执行的入参，仅当方法抛出异常时才输出。

1. $ watch test.arthas.TestWatch doGet {params[0], throwExp} -e

2. Press Ctrl+C to abort.

3. Affect(class-cnt:1 , method-cnt:1) cost in 65 ms.

4. ts=2018-09-18 10:26:28;result=@ArrayList[

5. @RequestFacade[org.apache.catalina.connector.RequestFacade@79f922b2],

6. @NullPointerException[java.lang.NullPointerException],

7. ]

Classloader

了解当前系统中有多少类加载器，以及每个加载器加载的类数量，帮助您判断是否有类加载器泄露。

1. $ classloader

2. name numberOfInstances loadedCountTotal

3. BootstrapClassLoader 1 3346

4. com.taobao.arthas.agent.ArthasClassloader 1 1262

5. java.net.URLClassLoader 2 1033

6. org.apache.catalina.loader.ParallelWebappClassLoader 1 628

7. sun.reflect.DelegatingClassLoader 166 166

8. sun.misc.Launcher$AppClassLoader 1 31

9. com.alibaba.fastjson.util.ASMClassLoader 6 15

10. sun.misc.Launcher$ExtClassLoader 1 7

11. org.jvnet.hk2.internal.DelegatingClassLoader 2 2

12. sun.reflect.misc.MethodUtil 1 1

Web Console

• https://alibaba.github.io/arthas/web-console