在linux下，中間件如weblogic，tomcat會進程資源飆高，如CPU,IO,memory。你可以用top,vmstat,iostat命令分別看，也可以用一個工具搞定就是pidstat，它不僅可以監控進程的性能情況，也可以監控線程的性能情況。

安裝：CentOS/Fedora/RHEL版本的linux中則使用下面的命令　　# yum install sysstat在Debian/Ubuntu系統中可以使用下面的命令來安裝　　# sudo apt-get install sysstat當然，也可以從這里下載 https://www.icewalkers.com/Linux/Software/59040/Sysstat.html寫一個demo模擬CPU飆高的情況：

public class PIDTestCPU {    public static class CPUTask implements Runnable{        public void run() {            while(true){                double a=Math.random()*Math.random();            }        }    }    public static class IdleTask implements Runnable{        public void run(){            try{                while(true){                    Thread.sleep(2000);                }            }catch(Exception e){            }        }    }    public static void main(String[] args){        new Thread(new CPUTask()).start();        new Thread(new IdleTask()).start();        new Thread(new IdleTask()).start();        new Thread(new IdleTask()).start();    }}[root@localhost ~]# java PIDTestCPU[root@localhost ~]# jps11161 PIDTestCPU11239 Jps[root@localhost ~]# pidstat -p  11161  1 3 -u -tLinux 2.6.32-431.el6.x86_64 (localhost.localdomain)     02/09/2017      _x86_64_        (1 CPU)06:11:03 PM      TGID       TID    %usr %system  %guest    %CPU   CPU  Command06:11:04 PM     11161         -  100.00    0.00    0.00  100.00     0  java06:11:04 PM         -     11161    0.00    0.00    0.00    0.00     0  |__java06:11:04 PM         -     11162    0.00    0.00    0.00    0.00     0  |__java06:11:04 PM         -     11163    0.00    0.00    0.00    0.00     0  |__java06:11:04 PM         -     11164    0.00    0.00    0.00    0.00     0  |__java06:11:04 PM         -     11165    0.00    0.00    0.00    0.00     0  |__java06:11:04 PM         -     11166    0.00    0.00    0.00    0.00     0  |__java06:11:04 PM         -     11167    0.00    0.00    0.00    0.00     0  |__java06:11:04 PM         -     11168    0.00    0.00    0.00    0.00     0  |__java06:11:04 PM         -     11169    0.00    0.00    0.00    0.00     0  |__java06:11:04 PM         -     11170    0.00    0.00    0.00    0.00     0  |__java06:11:04 PM         -     11171   99.00    0.00    0.00   99.00     0  |__java06:11:04 PM         -     11172    0.00    0.00    0.00    0.00     0  |__java06:11:04 PM         -     11173    0.00    0.00    0.00    0.00     0  |__java06:11:04 PM         -     11174    0.00    0.00    0.00    0.00     0  |__java十進制11171轉換為十六進制2ba32017-02-09 18:11:54Full thread dump Java HotSpot(TM) 64-Bit Server VM (20.45-b01 mixed mode):"DestroyJavaVM" PRio=10 tid=0x00007f7078006800 nid=0x2b9a waiting on condition [0x0000000000000000]   java.lang.Thread.State: RUNNABLE"Thread-3" prio=10 tid=0x00007f70780a7800 nid=0x2ba6 waiting on condition [0x00007f7069a64000]   java.lang.Thread.State: TIMED_WAITING (sleeping)        at java.lang.Thread.sleep(Native Method)        at PIDTestCPU$IdleTask.run(PIDTestCPU.java:13)        at java.lang.Thread.run(Thread.java:662)"Thread-2" prio=10 tid=0x00007f70780a5800 nid=0x2ba5 waiting on condition [0x00007f7069b65000]   java.lang.Thread.State: TIMED_WAITING (sleeping)        at java.lang.Thread.sleep(Native Method)        at PIDTestCPU$IdleTask.run(PIDTestCPU.java:13)        at java.lang.Thread.run(Thread.java:662)"Thread-1" prio=10 tid=0x00007f70780a3800 nid=0x2ba4 waiting on condition [0x00007f7069c66000]   java.lang.Thread.State: TIMED_WAITING (sleeping)        at java.lang.Thread.sleep(Native Method)        at PIDTestCPU$IdleTask.run(PIDTestCPU.java:13)        at java.lang.Thread.run(Thread.java:662)"Thread-0" prio=10 tid=0x00007f70780a1800 nid=0x2ba3 runnable [0x00007f7069d67000]   java.lang.Thread.State: RUNNABLE        at PIDTestCPU$CPUTask.run(PIDTestCPU.java:6)        at java.lang.Thread.run(Thread.java:662)"Low Memory Detector" daemon prio=10 tid=0x00007f7078088000 nid=0x2ba1 runnable [0x0000000000000000]   java.lang.Thread.State: RUNNABLE"C2 CompilerThread1" daemon prio=10 tid=0x00007f7078085800 nid=0x2ba0 waiting on condition [0x0000000000000000]   java.lang.Thread.State: RUNNABLE"C2 CompilerThread0" daemon prio=10 tid=0x00007f7078083000 nid=0x2b9f waiting on condition [0x0000000000000000]   java.lang.Thread.State: RUNNABLE"Signal Dispatcher" daemon prio=10 tid=0x00007f7078081000 nid=0x2b9e waiting on condition [0x0000000000000000]   java.lang.Thread.State: RUNNABLE"Finalizer" daemon prio=10 tid=0x00007f7078064000 nid=0x2b9d in Object.wait() [0x00007f707c22b000]   java.lang.Thread.State: WAITING (on object monitor)        at java.lang.Object.wait(Native Method)        - waiting on <0x00000000eb601300> (a java.lang.ref.ReferenceQueue$Lock)        at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:118)        - locked <0x00000000eb601300> (a java.lang.ref.ReferenceQueue$Lock)        at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:134)        at java.lang.ref.Finalizer$FinalizerThread.run(Finalizer.java:171)"Reference Handler" daemon prio=10 tid=0x00007f7078062000 nid=0x2b9c in Object.wait() [0x00007f707c32c000]   java.lang.Thread.State: WAITING (on object monitor)        at java.lang.Object.wait(Native Method)        - waiting on <0x00000000eb6011d8> (a java.lang.ref.Reference$Lock)        at java.lang.Object.wait(Object.java:485)        at java.lang.ref.Reference$ReferenceHandler.run(Reference.java:116)        - locked <0x00000000eb6011d8> (a java.lang.ref.Reference$Lock)"VM Thread" prio=10 tid=0x00007f707805b800 nid=0x2b9b runnable "VM Periodic Task Thread" prio=10 tid=0x00007f7078093000 nid=0x2ba2 waiting on condition JNI global references: 888Heap def new generation   total 4736K, used 446K [0x00000000eb600000, 0x00000000ebb20000, 0x00000000f08a0000)  eden space 4224K,  10% used [0x00000000eb600000, 0x00000000eb66fb30, 0x00000000eba20000)  from space 512K,   0% used [0x00000000eba20000, 0x00000000eba20000, 0x00000000ebaa0000)  to   space 512K,   0% used [0x00000000ebaa0000, 0x00000000ebaa0000, 0x00000000ebb20000) tenured generation   total 10624K, used 0K [0x00000000f08a0000, 0x00000000f1300000, 0x00000000fae00000)   the space 10624K,   0% used [0x00000000f08a0000, 0x00000000f08a0000, 0x00000000f08a0200, 0x00000000f1300000) compacting perm gen  total 21248K, used 2590K [0x00000000fae00000, 0x00000000fc2c0000, 0x0000000100000000)   the space 21248K,  12% used [0x00000000fae00000, 0x00000000fb0879f0, 0x00000000fb087a00, 0x00000000fc2c0000)pidstat -p  11161  1 3 -u -tCPU監控：pidstat -p指定進程ID，-u表示對CPU使用率監控，參數1 3 表示每秒采集1次，共采集三次%usr: 進程在用戶態運行所占cpu時間比率%system: 進程在內核態運行所占cpu時間比率%CPU: 進程運行所占cpu時間比率CPU: 指示進程在哪個核運行pidstat -p  11161  1 3 -d -tIO監控：pidstat -p指定進程ID，-d表示對磁盤IO使用率監控，參數1 3 表示每秒采集1次，共采集三次kB_rd/s: 每秒進程從磁盤讀取的數據量(以kB為單位)kB_wr/s: 每秒進程向磁盤寫的數據量(以kB為單位)pidstat -p  11161  1 3 -r -t內存監控：pidstat -p指定進程ID，-r表示對內存監控，參數1 3 表示每秒采集1次，共采集三次minflt/s：進程每秒不需要從磁盤中調出內存頁的總數majflt/s：進程每秒需要從磁盤中調出內存頁的總數，一般在內存使用緊張時產生VSZ：進程使用虛擬內存大小，單位KBrss:占用物理內存大小，單位KB%MEM:占用內存比率Average:         TGID       TID  minflt/s  majflt/s     VSZ    RSS   %MEM  CommandAverage:        11161         -      0.00      0.00 1059588  20552   2.03  javaAverage:            -     11161      0.00      0.00 1059588  20552   2.03  |__javaAverage:            -     11340      0.00      0.00 1059588  20552   2.03  |__javaAverage:            -     11341      0.00      0.00 1059588  20552   2.03  |__javaAverage:            -     11342      0.00      0.00 1059588  20552   2.03  |__javaAverage:            -     11343      0.00      0.00 1059588  20552   2.03  |__javaAverage:            -     11344      0.00      0.00 1059588  20552   2.03  |__javaAverage:            -     11345      0.00      0.00 1059588  20552   2.03  |__javaAverage:            -     11346      0.00      0.00 1059588  20552   2.03  |__javaAverage:            -     11347      0.00      0.00 1059588  20552   2.03  |__javaAverage:            -     11348      0.00      0.00 1059588  20552   2.03  |__javaAverage:            -     11349      0.00      0.00 1059588  20552   2.03  |__javaAverage:            -     11350      0.00      0.00 1059588  20552   2.03  |__javaAverage:            -     11351      0.00      0.00 1059588  20552   2.03  |__javaAverage:            -     11352      0.00      0.00 1059588  20552   2.03  |__java