表結構

student

?

class

Class

package auth.model;import javax.persistence.Column; import javax.persistence.Entity; import javax.persistence.GeneratedValue; import javax.persistence.GenerationType; import javax.persistence.Id; import javax.persistence.Table; @Entity @Table(name="class") public class Room { private int id; private String name; @Id @GeneratedValue(strategy= GenerationType.AUTO) @Column(name="id") public int getId() { return id; } public void setId(int id) { this.id = id; } @Column(name="name") public String getName() { return name; } public void setName(String name) { this.name = name; } }

Student

package auth.model;import javax.persistence.Column; import javax.persistence.Entity; import javax.persistence.GeneratedValue; import javax.persistence.GenerationType; import javax.persistence.Id; import javax.persistence.JoinColumn; import javax.persistence.ManyToOne; import javax.persistence.Table; @Entity @Table(name="student") public class Student { private int id; public int room_id; private String name; private Room room; @GeneratedValue(strategy= GenerationType.AUTO) @Id @Column(name="id") public int getId() { return id; } public void setId(int id) { this.id = id; } @Column(name="name") public String getName() { return name; } public void setName(String name) { this.name = name; } @Column(name="room_id") public int getRoom_id() { return room_id; } public void setRoom_id(int room_id) { this.room_id = room_id; } @ManyToOne @JoinColumn(name = "room_id",insertable=false, updatable=false) public Room getRoom() { return room; } public void setRoom(Room room) { this.room = room; } }

測試

package auth.controller;import org.springframework.beans.factory.annotation.Autowired; import org.springframework.stereotype.Service;import com.alibaba.fastjson.JSONObject;import auth.dao.ClassDao; import auth.dao.StudentDao; import auth.model.Room; import auth.model.Student; @Service public class StudentController { @Autowired private ClassDao dao; @Autowired private StudentDao stuDao; public void add(){ Room room=new Room(); room.setName("10班"); Student s=new Student(); dao.save(room); s.setName("小李5"); s.setRoom(room); stuDao.save(s); } public void query(){ Student s=stuDao.findOne(2); System.out.println(JSONObject.toJSONString(s)); } public void query1(){ Room s=dao.findOne(2); System.out.println(JSONObject.toJSONString(s)); } }

過程:

insert intoclass(name) values (?) auth.model.Room{name=11班, id=20} insert into student (name, room_id) values (?, ?) 2017-06-11 23:39:52,763 DEBUG [org.hibernate.id.IdentifierGeneratorHelper:94] - Natively generated identity: 24 2017-06-11 23:39:52,766 DEBUG [org.hibernate.engine.transaction.spi.AbstractTransactionImpl:175] - committing 2017-06-11 23:39:52,767 DEBUG [org.hibernate.event.internal.AbstractFlushingEventListener:149] - Processing flush-time cascades 2017-06-11 23:39:52,767 DEBUG [org.hibernate.event.internal.AbstractFlushingEventListener:189] - Dirty checking collections 2017-06-11 23:39:52,768 DEBUG [org.hibernate.event.internal.AbstractFlushingEventListener:123] - Flushed: 0 insertions, 0 updates, 0 deletions to 1 objects 2017-06-11 23:39:52,768 DEBUG [org.hibernate.event.internal.AbstractFlushingEventListener:130] - Flushed: 0 (re)creations, 0 updates, 0 removals to 0 collections 2017-06-11 23:39:52,772 DEBUG [org.hibernate.internal.util.EntityPrinter:114] - Listing entities: 2017-06-11 23:39:52,772 DEBUG [org.hibernate.internal.util.EntityPrinter:121] - auth.model.Student{room_id=0, name=小李6, id=24, room=auth.model.Room#20}
{"id":2,"name":"李明","room":{"id":1,"name":"12班"},"room_id":1}
{"id":2,"name":"24班"}

數據庫結果：

轉載于:https://www.cnblogs.com/JAYIT/p/6986480.html

總結

以上是生活随笔為你收集整理的jpa单向多对一关联映射的全部內容，希望文章能夠幫你解決所遇到的問題。

如果覺得生活随笔網站內容還不錯，歡迎將生活随笔推薦給好友。