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以Person，Student，Teacher三者的实现为例，关系如下图(Student和Teacher是Person类的子类)：

三种策略：

　　第一种(SINGLE_TABLE)：将所有类的字段都放在一个表之中,一张总表。

Person:

package com.bjsxt.hibernate;

import javax.persistence.DiscriminatorColumn;
import javax.persistence.DiscriminatorType;
import javax.persistence.DiscriminatorValue;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.Inheritance;
import javax.persistence.InheritanceType;

@Entity
@Inheritance(strategy=InheritanceType.SINGLE_TABLE)
@DiscriminatorColumn(name="discriminator",discriminatorType=DiscriminatorType.STRING)
@DiscriminatorValue("person")
public class Person {
    
    private Integer id;
    
    private String name;

    @Id
    @GeneratedValue
    public Integer getId() {
        return id;
    }

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

    public String getName() {
        return name;
    }

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

Student:

package com.bjsxt.hibernate;

import javax.persistence.DiscriminatorValue;
import javax.persistence.Entity;

@Entity
@DiscriminatorValue("student")
public class Student extends Person {
    
    private Integer score;

    public Integer getScore() {
        return score;
    }

    public void setScore(Integer score) {
        this.score = score;
    }
    
}

Teacher:

package com.bjsxt.hibernate;

import javax.persistence.DiscriminatorValue;
import javax.persistence.Entity;

@Entity
@DiscriminatorValue("teacher")
public class Teacher extends Person {
    private String title;

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }
}

jar包链接: https://pan.baidu.com/s/1gfh37wf 密码: rj2k

代码链接: https://pan.baidu.com/s/1c2062ek 密码: ix9t

　　第二种(TABLE_PER_CLASS)：每个表都是完整的信息，主键都取自一个中间表，以保持三个表主键的一致性,每个类分别一张表。

Person:

package com.bjsxt.hibernate;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Inheritance;
import javax.persistence.InheritanceType;
import javax.persistence.TableGenerator;

@Entity
@Inheritance(strategy=InheritanceType.TABLE_PER_CLASS)
@TableGenerator(
        name="t_gen",
        table="t_gen_table",
        pkColumnName="t_pk",//key的字段名
        valueColumnName="t_value",//value的字段名
        pkColumnValue="person_pk",//字段值
        initialValue=1,
        allocationSize=1
        )
public class Person {
    
    private Integer id;
    
    private String name;

    @Id
    @GeneratedValue(generator="t_gen",strategy=GenerationType.TABLE)
    public Integer getId() {
        return id;
    }

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

    public String getName() {
        return name;
    }

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

Student:

package com.bjsxt.hibernate;

import javax.persistence.Entity;

@Entity
public class Student extends Person {
    
    private Integer score;

    public Integer getScore() {
        return score;
    }

    public void setScore(Integer score) {
        this.score = score;
    }
    
}

Teacher:

package com.bjsxt.hibernate;

import javax.persistence.Entity;

@Entity
public class Teacher extends Person {
    private String title;

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }
}

jar包链接: https://pan.baidu.com/s/1gfh37wf 密码: rj2k

代码链接: https://pan.baidu.com/s/1bprLc9x 密码: 3dgi

　　第三种(JOINED)：子类对应的表和父类对应的表建立主键关联，每个子类一张表，父类对应的表保存公共属性字段，子类对应的表保存子类特有的对应字段。

Person:

package com.bjsxt.hibernate;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.Inheritance;
import javax.persistence.InheritanceType;

@Entity
@Inheritance(strategy=InheritanceType.JOINED)
public class Person {
    
    private Integer id;
    
    private String name;

    @Id
    @GeneratedValue()
    public Integer getId() {
        return id;
    }

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

    public String getName() {
        return name;
    }

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

Student:

package com.bjsxt.hibernate;

import javax.persistence.Entity;

@Entity
public class Student extends Person {
    
    private Integer score;

    public Integer getScore() {
        return score;
    }

    public void setScore(Integer score) {
        this.score = score;
    }
    
}

Teacher:

package com.bjsxt.hibernate;

import javax.persistence.Entity;

@Entity
public class Teacher extends Person {
    private String title;

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }
}

jar包链接: https://pan.baidu.com/s/1gfh37wf 密码: rj2k

代码链接: https://pan.baidu.com/s/1c12sjIw 密码: 1dzr