快速入门
===
## 1. 启动Demo
```bash
wget https://alibaba.github.io/arthas/arthas-demo.jar
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，再执行质因式分解，并打印出分解结果。
`arthas-demo`源代码：[查看](https://github.com/alibaba/arthas/blob/master/demo/src/main/java/demo/MathGame.java)
## 2. 启动arthas
在命令行下面执行：
```bash
wget https://alibaba.github.io/arthas/arthas-boot.jar
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attatch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：
```
[INFO] Try to attach process 71560
[INFO] Attach process 71560 success.
[INFO] arthas-client connect 127.0.0.1 3658
,---. ,------. ,--------.,--. ,--. ,---. ,---.
/ O \ | .--. ''--. .--'| '--' | / O \ ' .-'
| .-. || '--'.' | | | .--. || .-. |`. `-.
| | | || |\ \ | | | | | || | | |.-' |
`--' `--'`--' '--' `--' `--' `--'`--' `--'`-----'
wiki: https://alibaba.github.io/arthas
version: 3.0.5.20181127201536
pid: 71560
time: 2018-11-28 19:16:24
$
```
## 3. 查看dashboard
输入[dashboard](dashboard.md)，按enter/回车，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sysenv命令来获取到进程的Main Class
```
$ sysenv | grep MAIN
JAVA_MAIN_CLASS_71560 demo.MathGame
```
## 5. 通过jad来反编绎Main Class
```java
$ 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](watch.md)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](advanced-use.md)。
## 5. 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`shutdown`命令。