BaseEntity实体的继承：@MappedSuperclass

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在创建实体时，经常有重复的id和时间的属性要创建，所以想弄一个父类，然后所有实体继承，但是碰到了问题，就用到了@MappedSuperclass，它的的用法

用在实体的继承过程中的父类上；

如：

IdEntity.java

Java代码  

1. package com.zpf.test.Entity;
2. import java.io.Serializable;
3. import java.util.Date;
4. import javax.persistence.Column;
5. import javax.persistence.GeneratedValue;
6. import javax.persistence.GenerationType;
7. import javax.persistence.Id;
8. import javax.persistence.MappedSuperclass;
9. /**
10. * 基础实体类
11. *
12. * @author zpf
13. *
14. */
15. @MappedSuperclass
16. public class IdEntity implements Serializable {
17. /**
18. *
19. */
20. private static final long serialVersionUID = 1L;
21. @Id
22. @GeneratedValue(strategy = GenerationType.AUTO)
23. private long id;
24. @Column(updatable = false)
25. private Date createDate;
26. private Date modifyDate;
27. public long getId() {
28. return id;
29. }
30. public void setId(long id) {
31. this.id = id;
32. }
33. public Date getCreateDate() {
34. return createDate;
35. }
36. public void setCreateDate(Date createDate) {
37. this.createDate = createDate;
38. }
39. public Date getModifyDate() {
40. return modifyDate;
41. }
42. public void setModifyDate(Date modifyDate) {
43. this.modifyDate = modifyDate;
44. }
45. }

package com.zpf.test.Entity;

import java.io.Serializable;
import java.util.Date;

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

/**
 * 基础实体类
 *
 * @author zpf
 *
 */
@MappedSuperclass
public class IdEntity implements Serializable {

    /**
     *
     */
    private static final long serialVersionUID = 1L;

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private long id;

    @Column(updatable = false)
    private Date createDate;
    private Date modifyDate;

    public long getId() {
        return id;
    }

    public void setId(long id) {
        this.id = id;
    }

    public Date getCreateDate() {
        return createDate;
    }

    public void setCreateDate(Date createDate) {
        this.createDate = createDate;
    }

    public Date getModifyDate() {
        return modifyDate;
    }

    public void setModifyDate(Date modifyDate) {
        this.modifyDate = modifyDate;
    }

}

Java代码  

1. package com.zpf.test.Entity;
2. import java.io.Serializable;
3. import javax.persistence.Entity;
4. import javax.persistence.Table;
5. /**
6. * 用户实体
7. * @author zpf
8. *
9. */
10. @Entity
11. @Table(name="tb_user")
12. public class User extends IdEntity implements Serializable{
13. private static final long serialVersionUID = 1L;
14. private String name;
15. private String sex;
16. private int age;
17. public String getName() {
18. return name;
19. }
20. public void setName(String name) {
21. this.name = name;
22. }
23. public String getSex() {
24. return sex;
25. }
26. public void setSex(String sex) {
27. this.sex = sex;
28. }
29. public int getAge() {
30. return age;
31. }
32. public void setAge(int age) {
33. this.age = age;
34. }
35. }

package com.zpf.test.Entity;

import java.io.Serializable;

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

/**
 * 用户实体
 * @author zpf
 *
 */
@Entity
@Table(name="tb_user")
public class User extends IdEntity implements Serializable{

    private static final long serialVersionUID = 1L;

    private String name;

    private String sex;

    private int age;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getSex() {
        return sex;
    }

    public void setSex(String sex) {
        this.sex = sex;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

}

这样就会生成tb_user表而且包含父类属性，否则只会生成一张identity表，字段有：id，crearedate,modifydate,name，sex，age
原文地址：https://www.iteye.com/blog/peng13123-2062980

原文地址：https://www.cnblogs.com/jpfss/p/12083639.html