JPA双向一对一关联关系@OneToOne

雨点打透心脏的1/2处 2022-05-20 08:16 342阅读 0赞

Department.class

package com.jpa.helloworld;
    
    import javax.persistence.Column;
    import javax.persistence.Entity;
    import javax.persistence.GeneratedValue;
    import javax.persistence.Id;
    import javax.persistence.JoinColumn;
    import javax.persistence.OneToOne;
    import javax.persistence.Table;
    
    @Table(name="DEPARTMET")
    @Entity
    public class Department {
    
    	private Integer depId;
    
    	private String depName;
    
    	private Manager mar;
    
    	@GeneratedValue
    	@Column(name="DEP_ID")
    	@Id
    	public Integer getDepId() {
    		return depId;
    	}
    
    	public void setDepId(Integer depId) {
    		this.depId = depId;
    	}
    
    	@Column(name="DEP_NAME")
    	public String getDepName() {
    		return depName;
    	}
    
    	public void setDepName(String depName) {
    		this.depName = depName;
    	}
    
    	//这是维护关联关系的一方
    	//在这一边加入外键列，列名为MAR_ID,并且将该列设置为唯一约束
    	@JoinColumn(name="MAR_ID",unique=true)
    	@OneToOne
    	public Manager getMar() {
    		return mar;
    	}
    
    	public void setMar(Manager mar) {
    		this.mar = mar;
    	}
    
    }

Manager.class

package com.jpa.helloworld;
    
    import javax.persistence.Column;
    import javax.persistence.Entity;
    import javax.persistence.GeneratedValue;
    import javax.persistence.Id;
    import javax.persistence.OneToOne;
    import javax.persistence.Table;
    
    @Table(name="MANAGER")
    @Entity
    public class Manager {
    
    	private Integer marId;
    
    	private String marName;
    
    	private Department dept;
    
    	@GeneratedValue
    	@Id
    	@Column(name="MAR_ID")
    	public Integer getMarId() {
    		return marId;
    	}
    
    	public void setMarId(Integer marId) {
    		this.marId = marId;
    	}
    
    	@Column(name="MAR_NAME")
    	public String getMarName() {
    		return marName;
    	}
    
    	public void setMarName(String marName) {
    		this.marName = marName;
    	}
    
    	//这是不维护关联关系的一方
    	//添加mappedBy属性，则该方不维护关联关系
    	//mappedBy的属性为维护关联关系一方的属性名
    	@OneToOne(mappedBy="mar")
    	public Department getDept() {
    		return dept;
    	}
    	public void setDept(Department dept) {
    		this.dept = dept;
    	}
    
    }