模拟线上排查内存占用高的问题
1、模拟代码如下
package com.jiankunking.memory;
import org.springframework.stereotype.Component;
import javax.annotation.PostConstruct;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
/**
* Created by jiankunking on 2018/3/29.
*/
@Component
public class memReaper
@PostConstruct
public void memReaper() {
long start = System.currentTimeMillis() / 1000;
List<Map> list = new ArrayList<>();
while (true) {
HashMap<String, String> map = new HashMap<>();
map.put("aaa", "nnnn");
list.add(map);
if (list.size() > 3000000) {
System.out.println("clear");
list.clear();
}
if ((System.currentTimeMillis() / 1000) - start > 1000) {
return;
}
}
}
}
2、打包
mvn clean package -Dmaven.test.skip=true
3、部署运行
java -jar cpu-mem-occupy-simulate-0.0.1-SNAPSHOT.jar
4、查看系统资源占用情况
top
5、根据PID dump heap文件
jmap -dump:live,format=b,file=heap_dump 3638
6、安装下载MAT工具
http://www.eclipse.org/mat/7、用mat工具打开第5步中的文件
找到Problem Suspect
点击打开See stacktrace.如下：
.util.HashMap.putVal(ILjava/lang/Object;Ljava/lang/Object;ZZ)Ljava/lang/Object; (HashMap.java:628)
at java.util.HashMap.put(Ljava/lang/Object;Ljava/lang/Object;)Ljava/lang/Object; (HashMap.java:611)
//注意这里 内存占用高的地方
at com.jiankunking.memory.memReaper.memReaper()V (memReaper.java:22)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Ljava/lang/reflect/Method;Ljava/lang/Object;[Ljava/lang/Object;)Ljava/lang/Object; (Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Ljava/lang/Object;[Ljava/lang/Object;)Ljava/lang/Object; (NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Ljava/lang/Object;[Ljava/lang/Object;)Ljava/lang/Object; (DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Ljava/lang/Object;[Ljava/lang/Object;)Ljava/lang/Object; (Method.java:498)
at org.springframework.beans.factory.annotation.InitDestroyAnnotationBeanPostProcessor$LifecycleElement.invoke(Ljava/lang/Object;)V (InitDestroyAnnotationBeanPostProcessor.java:369)
at org.springframework.beans.factory.annotation.InitDestroyAnnotationBeanPostProcessor$LifecycleMetadata.invokeInitMethods(Ljava/lang/Object;Ljava/lang/String;)V (InitDestroyAnnotationBeanPostProcessor.java:312)
at org.springframework.beans.factory.annotation.InitDestroyAnnotationBeanPostProcessor.postProcessBeforeInitialization(Ljava/lang/Object;Ljava/lang/String;)Ljava/lang/Object; (InitDestroyAnnotationBeanPostProcessor.java:135)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyBeanPostProcessorsBeforeInitialization(Ljava/lang/Object;Ljava/lang/String;)Ljava/lang/Object; (AbstractAutowireCapableBeanFactory.java:423)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(Ljava/lang/String;Ljava/lang/Object;Lorg/springframework/beans/factory/support/RootBeanDefinition;)Ljava/lang/Object; (AbstractAutowireCapableBeanFactory.java:1702)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(Ljava/lang/String;Lorg/springframework/beans/factory/support/RootBeanDefinition;[Ljava/lang/Object;)Ljava/lang/Object; (AbstractAutowireCapableBeanFactory.java:583)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(Ljava/lang/String;Lorg/springframework/beans/factory/support/RootBeanDefinition;[Ljava/lang/Object;)Ljava/lang/Object; (AbstractAutowireCapableBeanFactory.java:502)
at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(Ljava/lang/String;Lorg/springframework/beans/factory/support/RootBeanDefinition;[Ljava/lang/Object;)Ljava/lang/Object; (AbstractBeanFactory.java:312)
at org.springframework.beans.factory.support.AbstractBeanFactory$$Lambda$73.getObject()Ljava/lang/Object; (Unknown Source)
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(Ljava/lang/String;Lorg/springframework/beans/factory/ObjectFactory;)Ljava/lang/Object; (DefaultSingletonBeanRegistry.java:228)
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(Ljava/lang/String;Ljava/lang/Class;[Ljava/lang/Object;Z)Ljava/lang/Object; (AbstractBeanFactory.java:310)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(Ljava/lang/String;)Ljava/lang/Object; (AbstractBeanFactory.java:200)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons()V (DefaultListableBeanFactory.java:760)
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(Lorg/springframework/beans/factory/config/ConfigurableListableBeanFactory;)V (AbstractApplicationContext.java:868)
at org.springframework.context.support.AbstractApplicationContext.refresh()V (AbstractApplicationContext.java:549)
at org.springframework.boot.SpringApplication.refresh(Lorg/springframework/context/ApplicationContext;)V (SpringApplication.java:752)
at org.springframework.boot.SpringApplication.refreshContext(Lorg/springframework/context/ConfigurableApplicationContext;)V (SpringApplication.java:388)
at org.springframework.boot.SpringApplication.run([Ljava/lang/String;)Lorg/springframework/context/ConfigurableApplicationContext; (SpringApplication.java:327)
at org.springframework.boot.SpringApplication.run([Ljava/lang/Class;[Ljava/lang/String;)Lorg/springframework/context/ConfigurableApplicationContext; (SpringApplication.java:1246)
at org.springframework.boot.SpringApplication.run(Ljava/lang/Class;[Ljava/lang/String;)Lorg/springframework/context/ConfigurableApplicationContext; (SpringApplication.java:1234)
at com.jiankunking.CpuMemOccupySimulateApplication.main([Ljava/lang/String;)V (CpuMemOccupySimulateApplication.java:10)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Ljava/lang/reflect/Method;Ljava/lang/Object;[Ljava/lang/Object;)Ljava/lang/Object; (Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Ljava/lang/Object;[Ljava/lang/Object;)Ljava/lang/Object; (NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Ljava/lang/Object;[Ljava/lang/Object;)Ljava/lang/Object; (DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Ljava/lang/Object;[Ljava/lang/Object;)Ljava/lang/Object; (Method.java:498)
at org.springframework.boot.loader.MainMethodRunner.run()V (MainMethodRunner.java:48)
at org.springframework.boot.loader.Launcher.launch([Ljava/lang/String;Ljava/lang/String;Ljava/lang/ClassLoader;)V (Launcher.java:87)
at org.springframework.boot.loader.Launcher.launch([Ljava/lang/String;)V (Launcher.java:50)
at org.springframework.boot.loader.JarLauncher.main([Ljava/lang/String;)V (JarLauncher.java:51)
8、原因明确 问题解决。
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作者：jiankunking
