jvm查看类的引用及创建

1、jmap查看创建的实例 解决一次Spring注解生成空bean的过程。

原因：ContextLoaderListener和DispatcherServlet 父子关系导致的空bean。

首先查看端口 FanXin为执行类

查看目标类实例个数 Student为类名

dump出进程镜像

jhat查看引用关系

登陆localhost：7000 查看类的引用关系

classStudent-->Exclude subclasses-->Student@0x76ada5e60 (28 bytes) 

References to this object:引用该实体类的对象

ce shi dai ma

public class Student {    private int id;    private String name;    public Student(int id,String name){        this.id=id;        this.name=name;    }    public void setId(int id){        this.id=id;    }    public void setName(String name){        this.name=name;    }    public int getId(){        return id;    }    public String getName(){        return name;    }}

public class FanXin {    private static Student student=new Student(1,"zcl");    public Student getStudent(){        return student;    }    public static void main(String[]args){        FanXin fanXin=new FanXin();        Student student=fanXin.getStudent();        while(true){            int id=student.getId();        }//        System.out.println(student.getId());    }}