JVM 频繁full gc / oom内存溢出/ 分析工具 jmap/Jconsole 用法

偏执的太偏执、 2021-09-23 04:58 517阅读 0赞

分析解决方法：

1 用JVisualVM 或Jconsole 分析 进程（不用jmap dump出镜像，JVisualVM功能比Jconsole强大）

2 先用jmap dump出镜像，再导入mat分析

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Java内存分析工具MAT(Memory Analyzer Tool)

JVisualVM是一个集成多个JDK命令行工具的可视化工具。可以作为Java应用程序性能分析和运行监控的工具。

[Jconsole][]是JDK自带的[监控][Jconsole]工具，在JDK/bin目录下可以找到。它用于连接正在运行的本地或者远程的[JVM][Jconsole]，对运行在[java][Jconsole]应用程序的资源消耗和性能进行监控，并画出大量的图表，提供强大的可视化界面。而且本身占用的服务器内存很小，甚至可以说几乎不消耗。

Jhat (Java Heap Analysis Tool)

[https://programskills.blog.csdn.net/article/details/114169046][https_programskills.blog.csdn.net_article_details_114169046]  《JVM性能监控于故障处理工具 jps/ jstat/jinfo/jmap/jhat/jstack/HSDIS/jconsole/jvisualvm》

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ZBMAC-f2b04ccbd:~ **zhangsan**$ jmap -help

Usage:

jmap \[option\] <pid>

(to connect to running process)

jmap \[option\] <executable <core>

(to connect to a core file)

jmap \[option\] \[server\_id@\]<remote server IP or hostname>

(to connect to remote debug server)

where <option> is one of:

<none>               to print same info as Solaris pmap

-heap                to print java heap summary

-histo\[:live\]        to print histogram of java object heap; if the "live"

suboption is specified, only count live objects

-clstats             to print class loader statistics

-finalizerinfo       to print information on objects awaiting finalization

-dump:<dump-options> to dump java heap in hprof binary format

dump-options:

live         dump only live objects; if not specified,

all objects in the heap are dumped.

format=b     binary format

file=<file>  dump heap to <file>

Example: jmap -dump:live,format=b,file=heap.bin <pid>

-F                   force. Use with -dump:<dump-options> <pid> or -histo

to force a heap dump or histogram when <pid> does not

respond. The "live" suboption is not supported

in this mode.

-h | -help           to print this help message

-J<flag>             to pass <flag> directly to the runtime system

**ZBMAC-f2b04ccbd:~ zhangsan$ jmap -dump:format=b,file=dumpv1 83511  \#把进程83511的堆信息打印出来**

**Dumping heap to /Users/zhangsan/dumpv1 ...**

**Heap dump file created**

**ZBMAC-f2b04ccbd:~ zhangsan$ **

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ZBMAC-f2b04ccbd:~ zhangsan$ jconsole

输入jconsole后，会自动打开，先选择一个进程，再连接

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mac jdk1.8

[Jconsole]: http://www.51testing.com/?uid-116228-act%3Cwbr%3Eion-viewspace-itemid-149296
[https_programskills.blog.csdn.net_article_details_114169046]: https://programskills.blog.csdn.net/article/details/114169046
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