**1.通过ps -ef|grep {*program*Name} 找到程序进程ID

[root@10 keep_rule_sender]# ps -ef|grep java
root      4896 18614  0 15:52 pts/0    00:00:00 grep --color=auto java
root     15550 15547  0 5月25 ?       00:24:08 ./jre/bin/java -jar -Dfile.encoding=UTF-8 -XX:+UseG1GC -Xms16384M -Xmx16384M -Xmn8192M -Xss2M AuthCenter.jar

2.top -Hp pid 查看该进程对应的各个线程的运行状态

[root@10 keep_rule_sender]# top Hp 15550
top - 15:55:19 up 115 days, 54 min,  1 user,  load average: 0.31, 0.36, 0.40
Threads: 146 total,   0 running, 146 sleeping,   0 stopped,   0 zombie
%Cpu(s):  3.2 us,  0.7 sy,  0.0 ni, 96.1 id,  0.0 wa,  0.0 hi,  0.1 si,  0.0 st
KiB Mem : 13157919+total, 62099732 free, 26188756 used, 43290704 buff/cache
KiB Swap:  4194300 total,  4194300 free,        0 used. 10426378+avail Mem
  PID USER      PR  NI    VIRT    RES    SHR S %CPU %MEM     TIME+ COMMAND                                                                                                                                      
15937 root      20   0 27.453g 9.252g  13756 S  0.3  7.4   0:16.47 java                                                                                                                                         
15947 root      20   0 27.453g 9.252g  13756 S  0.3  7.4   0:16.73 java

3.jstack pid > stack.txt 保存该程序各个线程当前的执行状态到本地文件stack.txt中

4.查看对应线程的状态

把top看到的线程号（pid）转换成16进制

在stack.txt文件中查看对应线程的执行状态

"nioEventLoopGroup-3-52" #78 prio=10 os_prio=0 tid=0x00007fe8b012c000 nid=0x3e41 runnable [0x00007fe7eb7fa000]
java.lang.Thread.State: RUNNABLE
  at sun.nio.ch.EPollArrayWrapper.epollWait(Native Method)
  at sun.nio.ch.EPollArrayWrapper.poll(EPollArrayWrapper.java:269)
  at sun.nio.ch.EPollSelectorImpl.doSelect(EPollSelectorImpl.java:79)
  at sun.nio.ch.SelectorImpl.lockAndDoSelect(SelectorImpl.java:86)
  - locked <0x00000003c0056660> (a io.netty.channel.nio.SelectedSelectionKeySet)
  - locked <0x00000003c0056608> (a java.util.Collections$UnmodifiableSet)
  - locked <0x00000003c0056618> (a sun.nio.ch.EPollSelectorImpl)
  at sun.nio.ch.SelectorImpl.select(SelectorImpl.java:97)
  at io.netty.channel.nio.NioEventLoop.select(NioEventLoop.java:639)
  at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:325)
  at io.netty.util.concurrent.SingleThreadEventExecutor$2.run(SingleThreadEventExecutor.java:112)
  at io.netty.util.concurrent.DefaultThreadFactory$DefaultRunnableDecorator.run(DefaultThreadFactory.java:137)
  at java.lang.Thread.run(Thread.java:745)