Java自己有很多优秀的调试工具，可以帮助分析系统的漏洞，瓶颈，这里列举几个自己常用的命令：
jps -l 查看现有的java进程 jps -l 显示所有正在运行的java进程id jstack查看Java线程 jstack -l pid; 做thread dump，直接打印在串口
jstack pid>> ./threaddumps 输出到指定文件分析 jmap 查看Java内存使用情况 jmap -histo:live pid 对象占用内存排名
jmap -dump:file=memroydumps pid 把heap dump到文件 jhat
通过查看jmap dump文件分析
jhat ./threaddumps 分析dump文件
d:\cloudlu\workspace\CustomerSecurityManagementSystem\CustomerSecurityManagementWeb>jmap -dump:file=test.map 6860
Dumping heap to D:\cloudlu\workspace\CustomerSecurityManagementSystem\CustomerSecurityManagementWeb\test.map ...
Heap dump file created
d:\cloudlu\workspace\CustomerSecurityManagementSystem\CustomerSecurityManagementWeb>jhat test.map
Reading from test.map...
Dump file created Wed Jun 04 10:49:22 CST 2014
Snapshot read, resolving...
Resolving 1982196 objects...
Chasing references, expect 396 dots.........................................................................................................
............................................................................................................................................
............................................................................................................................................
...........
Eliminating duplicate references............................................................................................................
............................................................................................................................................
............................................................................................................................................
........
Snapshot resolved.
Started HTTP server on port 7000
Server is ready.
http://localhost:7000 查看分析结果
jstat
查看heap内各个部分的使用量，以及加载类的数量以及GC的相关信息。
jstat -options (查看参数) / jstat -help
jstat -gcutil -t -h 3 6860 200 10
Timestamp S0 S1 E O M CCS YGC YGCT FGC FGCT GCT
2930.6 0.00 0.00 31.53 60.00 91.23 82.55 80 1.622 5 6.644 8.266
2930.8 0.00 0.00 31.53 60.00 91.23 82.55 80 1.622 5 6.644 8.266
2931.0 0.00 0.00 31.53 60.00 91.23 82.55 80 1.622 5 6.644 8.266
Timestamp S0 S1 E O M CCS YGC YGCT FGC FGCT GCT
2931.2 0.00 0.00 31.53 60.00 91.23 82.55 80 1.622 5 6.644 8.266
2931.4 0.00 0.00 31.53 60.00 91.23 82.55 80 1.622 5 6.644 8.266
2931.6 0.00 0.00 31.53 60.00 91.23 82.55 80 1.622 5 6.644 8.266
Timestamp S0 S1 E O M CCS YGC YGCT FGC FGCT GCT
2931.8 0.00 0.00 31.53 60.00 91.23 82.55 80 1.622 5 6.644 8.266
2932.0 0.00 0.00 31.53 60.00 91.23 82.55 80 1.622 5 6.644 8.266
2932.2 0.00 0.00 31.53 60.00 91.23 82.55 80 1.622 5 6.644 8.266
Timestamp S0 S1 E O M CCS YGC YGCT FGC FGCT GCT
2932.4 0.00 0.00 31.53 60.00 91.23 82.55 80 1.622 5 6.644 8.266
jdk自带的hprof
启动应用时带上hprof参数，查看cpu，内存使用情况
java -agentlib:hprof=cpu=times,interval=20,depth=10 -jar start.jar
http://www.cnblogs.com/linhaohong/archive/2012/07/12/2588657.html
Jconsole&Jvisualvm
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