hibernate ——联合主键

Posted 2020-07-18 沙中世界

接上一篇博客：http://www.cnblogs.com/tengpan-cn/p/5551323.html

 

主键类不需要写任何注解，表对象类使用@IdClass注解

在表对象类前面加@IdClass(value=主键类名.class)然后，表对象类中也不必包含主键类，直接分成各个属性即可。在多个属性前加@ID

 

添加主键类，注意必须实现Serializable接口

package com.pt.hibernate;

import java.io.Serializable;

public class UnionId implements Serializable{
    public String getSchoolName() {
        return schoolName;
    }
    public void setSchoolName(String schoolName) {
        this.schoolName = schoolName;
    }
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    String schoolName;
    int id;
}

UnionId.java

package com.pt.hibernate;

import javax.persistence.Entity;
import javax.persistence.Id;
import javax.persistence.IdClass;

@Entity
@IdClass(value=UnionId.class)
public class Student {
    String schoolName;
    int id;
    String stuName;
    
    public String getStuName() {
        return stuName;
    }
    public void setStuName(String stuName) {
        this.stuName = stuName;
    }
    @Id
    public String getSchoolName() {
        return schoolName;
    }
    public void setSchoolName(String schoolName) {
        this.schoolName = schoolName;
    }
    @Id
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }

}

Student.java

生成表的语句：

create table Student (
        id integer not null,
        schoolName varchar(255) not null,
        stuName varchar(255),
        primary key (id, schoolName)
    ) ENGINE=InnoDB