@MappedSuperclass

@MappedSuperclass的用法
用在实体的继承过程中的父类上；

父类Cat

Java代码  

 package com.xj.model;

 import javax.persistence.GeneratedValue;
 import javax.persistence.Id;
 import javax.persistence.MappedSuperclass;

 @MappedSuperclass
 public class Base {
     private Long id;
     private String name;
     @Id
     @GeneratedValue
     public Long getId() {
         return id;
     }
     public void setId(Long id) {
         this.id = id;
     }
     public String getName() {
         return name;
     }
     public void setName(String name) {
         this.name = name;
     }
 }

子类1 BeijingCat

Java代码  

 package com.xj.model;

 import javax.persistence.Entity;
 import javax.persistence.Table;

 @Entity
 @Table(name="t_lj")
 public class Lj extends Base {
     private String lj;

     public String getLj() {
         return beijing;
     }

     public void setLj(String Lj) {
         this.lj= Lj;
     }

 }

子类2 ShanghaiCat

Java代码  

 package com.xj.model;

 import javax.persistence.Entity;
 import javax.persistence.Table;

 @Entity
 @Table(name="t_wp")
 public class Wp extends Base{
     private String wp;

     public String getWp() {
         return shanghai;
     }

     public void setWp(String Wp) {
         this.wp= Wp;
     }
 }

结果生成 两张表t_lj、 t_wp 

如果不用@MappedSuperclass 而用@Entity替换的话，只会生成一张Base表，字段有：id，name，lj，wp