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());
    }
}