快速入门
1. 启动Demo
1. curl -O https://arthas.aliyun.com/arthas-demo.jar 2. java -jar arthas-demo.jar
arthas-demo是一个简单的程序，每隔一秒生成一个随机数，再执行质因数分解，并打印出分解结果。
arthas-demo源代码：查看
2. 启动arthas
在命令行下面执行（使用和目标进程一致的用户启动，否则可能attach失败）：
1. curl -O https://arthas.aliyun.com/arthas-boot.jar 2. java -jar arthas-boot.jar
- 执行该程序的用户需要和目标进程具有相同的权限。比如以
admin用户来执行：sudo su admin && java -jar arthas-boot.jar或sudo -u admin -EH java -jar arthas-boot.jar。 - 如果attach不上目标进程，可以查看
~/logs/arthas/目录下的日志。 - 如果下载速度比较慢，可以使用aliyun的镜像：
java -jar arthas-boot.jar --repo-mirror aliyun --use-http java -jar arthas-boot.jar -h打印更多参数信息。
选择应用java进程：
$ $ java -jar arthas-boot.jar * [1]: 35542 [2]: 71560 arthas-demo.jar
Demo进程是第2个，则输入2，再输入回车/enter。Arthas会attach到目标进程上，并输出日志：
1. [INFO] Try to attach process 71560 2. [INFO] Attach process 71560 success. 3. [INFO] arthas-client connect 127.0.0.1 3658 4. ,---. ,------. ,--------.,--. ,--. ,---. ,---. 5. / O \ | .--. ''--. .--'| '--' | / O \ ' .-' 6. | .-. || '--'.' | | | .--. || .-. |`. `-. 7. | | | || |\ \ | | | | | || | | |.-' | 8. `--' `--'`--' '--' `--' `--' `--'`--' `--'`-----' 9. 10. wiki: https://arthas.aliyun.com/doc 11. version: 3.0.5.20181127201536 12. pid: 71560 13. time: 2018-11-28 19:16:24 14. 15. $
3. 查看dashboard
输入dashboard，按回车/enter，会展示当前进程的信息，按ctrl+c可以中断执行。
$ dashboard ID NAME GROUP PRIORI STATE %CPU TIME INTERRU DAEMON 17 pool-2-thread-1 system 5 WAITIN 67 0:0 false false 27 Timer-for-arthas-dashb system 10 RUNNAB 32 0:0 false true 11 AsyncAppender-Worker-a system 9 WAITIN 0 0:0 false true 9 Attach Listener system 9 RUNNAB 0 0:0 false true 3 Finalizer system 8 WAITIN 0 0:0 false true 2 Reference Handler system 10 WAITIN 0 0:0 false true 4 Signal Dispatcher system 9 RUNNAB 0 0:0 false true 26 as-command-execute-dae system 10 TIMED_ 0 0:0 false true 13 job-timeout system 9 TIMED_ 0 0:0 false true 1 main main 5 TIMED_ 0 0:0 false false 14 nioEventLoopGroup-2-1 system 10 RUNNAB 0 0:0 false false 18 nioEventLoopGroup-2-2 system 10 RUNNAB 0 0:0 false false 23 nioEventLoopGroup-2-3 system 10 RUNNAB 0 0:0 false false 15 nioEventLoopGroup-3-1 system 10 RUNNAB 0 0:0 false false Memory used total max usage GC heap 32M 155M 1820M 1.77% gc.ps_scavenge.count 4 ps_eden_space 14M 65M 672M 2.21% gc.ps_scavenge.time(m 166 ps_survivor_space 4M 5M 5M s) ps_old_gen 12M 85M 1365M 0.91% gc.ps_marksweep.count 0 nonheap 20M 23M -1 gc.ps_marksweep.time( 0 code_cache 3M 5M 240M 1.32% ms) Runtime os.name Mac OS X os.version 10.13.4 java.version 1.8.0_162 java.home /Library/Java/JavaVir tualMachines/jdk1.8.0 _162.jdk/Contents/Hom e/jre
4. 通过thread命令来获取到arthas-demo进程的Main Class
thread 1会打印线程ID 1的栈，通常是main函数的线程。
1. $ thread 1 | grep 'main(' 2. at demo.MathGame.main(MathGame.java:17)
5. 通过jad来反编译Main Class
$ jad demo.MathGame ClassLoader: +-sun.misc.Launcher$AppClassLoader@3d4eac69 +-sun.misc.Launcher$ExtClassLoader@66350f69 Location: /tmp/arthas-demo.jar /* * Decompiled with CFR 0_132. */ package demo; import java.io.PrintStream; import java.util.ArrayList; import java.util.Iterator; import java.util.List; import java.util.Random; import java.util.concurrent.TimeUnit; public class MathGame { private static Random random = new Random(); private int illegalArgumentCount = 0; public static void main(String[] args) throws InterruptedException { MathGame game = new MathGame(); do { game.run(); TimeUnit.SECONDS.sleep(1L); } while (true); } public void run() throws InterruptedException { try { int number = random.nextInt(); List<Integer> primeFactors = this.primeFactors(number); MathGame.print(number, primeFactors); } catch (Exception e) { System.out.println(String.format("illegalArgumentCount:%3d, ", this.illegalArgumentCount) + e.getMessage()); } } public static void print(int number, List<Integer> primeFactors) { StringBuffer sb = new StringBuffer("" + number + "="); Iterator<Integer> iterator = primeFactors.iterator(); while (iterator.hasNext()) { int factor = iterator.next(); sb.append(factor).append('*'); } if (sb.charAt(sb.length() - 1) == '*') { sb.deleteCharAt(sb.length() - 1); } System.out.println(sb); } public List<Integer> primeFactors(int number) { if (number < 2) { ++this.illegalArgumentCount; throw new IllegalArgumentException("number is: " + number + ", need >= 2"); } ArrayList<Integer> result = new ArrayList<Integer>(); int i = 2; while (i <= number) { if (number % i == 0) { result.add(i); number /= i; i = 2; continue; } ++i; } return result; } } Affect(row-cnt:1) cost in 970 ms.
6. watch
通过watch命令来查看demo.MathGame#primeFactors函数的返回值：
$ watch demo.MathGame primeFactors returnObj Press Ctrl+C to abort. Affect(class-cnt:1 , method-cnt:1) cost in 107 ms. ts=2018-11-28 19:22:30; [cost=1.715367ms] result=null ts=2018-11-28 19:22:31; [cost=0.185203ms] result=null ts=2018-11-28 19:22:32; [cost=19.012416ms] result=@ArrayList[ @Integer[5], @Integer[47], @Integer[2675531], ] ts=2018-11-28 19:22:33; [cost=0.311395ms] result=@ArrayList[ @Integer[2], @Integer[5], @Integer[317], @Integer[503], @Integer[887], ] ts=2018-11-28 19:22:34; [cost=10.136007ms] result=@ArrayList[ @Integer[2], @Integer[2], @Integer[3], @Integer[3], @Integer[31], @Integer[717593], ] ts=2018-11-28 19:22:35; [cost=29.969732ms] result=@ArrayList[ @Integer[5], @Integer[29], @Integer[7651739], ]
更多的功能可以查看进阶使用。
7. 退出arthas
如果只是退出当前的连接，可以用quit或者exit命令。Attach到目标进程上的arthas还会继续运行，端口会保持开放，下次连接时可以直接连接上。
如果想完全退出arthas，可以执行stop命令。
