Hibernate OneToOne注解关联查询案例

hibernate 的OneToOne注解是把两张表关联起来
下面是案例：
把User（用户表）表和Customer（客户表）关联起来
User表对应的实体类如下：

package com.pms.login.pojo;


import java.util.Date;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.SequenceGenerator;
import javax.persistence.Table;
import javax.persistence.UniqueConstraint;

import org.springframework.format.annotation.DateTimeFormat;

import com.fasterxml.jackson.annotation.JsonFormat;

@Entity
@Table(name="MAPS_MST_STAFF")
@SequenceGenerator (name = "SEQ", sequenceName = "MST_STAFF_SEQ", allocationSize = 1) 
public class User {

    @Id  
    @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "SEQ") 
    @Column(name = "id")  
    private Integer id;
    //员工编号
    @Column(name="STAFF_ID")
    private String staffId;
    //员工姓名
    @Column(name="STAFF_NAME")
    private String staffName;
    //登录名
    @Column(name="STAFF_LOGIN_NAME")
    private String staffLoginName;
    //员工角色
    @Column(name="STAFF_CHARACTOR")
    private String staffCharactor;
    //开始时间
    @Column(name="START_DT")
    @DateTimeFormat(pattern = "yyyy-MM-dd HH:mm:ss")
    @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss", timezone = "GMT+8")
    private Date startDate;
    //结束时间
    @Column(name="END_DT")
    @DateTimeFormat(pattern = "yyyy-MM-dd HH:mm:ss")
    @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss", timezone = "GMT+8")
    private Date endDate;
    //联系电话
    @Column(name="STAFF_TEL")
    private String staffTel;
    //员工性别
    @Column(name="STAFF_SEX")
    private String staffSex;
    //密码
    @Column(name="STAFF_PASS")
    private String staffPass;
    //密码有效期
    @Column(name="PASS_END_DT")
    @DateTimeFormat(pattern = "yyyy-MM-dd HH:mm:ss")
    @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss", timezone = "GMT+8")
    private Date passEndDate;
    //是否能登陆
    @Column(name="LOGIN_FLG")
    private String loginFlg;



    public User(){

    }

    public User(Integer id, String staffId, String staffName, String staffLoginName, String staffCharactor,
            Date startDate, Date endDate, String staffTel, String staffSex, String staffPass, Date passEndDate,
            String loginFlg) {
        super();
        this.id = id;
        this.staffId = staffId;
        this.staffName = staffName;
        this.staffLoginName = staffLoginName;
        this.staffCharactor = staffCharactor;
        this.startDate = startDate;
        this.endDate = endDate;
        this.staffTel = staffTel;
        this.staffSex = staffSex;
        this.staffPass = staffPass;
        this.passEndDate = passEndDate;
        this.loginFlg = loginFlg;
    }
    public Integer getId() {
        return id;
    }
    public void setId(Integer id) {
        this.id = id;
    }
    public String getStaffId() {
        return staffId;
    }
    public void setStaffId(String staffId) {
        this.staffId = staffId;
    }
    public String getStaffName() {
        return staffName;
    }
    public void setStaffName(String staffName) {
        this.staffName = staffName;
    }
    public String getStaffLoginName() {
        return staffLoginName;
    }
    public void setStaffLoginName(String staffLoginName) {
        this.staffLoginName = staffLoginName;
    }
    public String getStaffCharactor() {
        return staffCharactor;
    }
    public void setStaffCharactor(String staffCharactor) {
        this.staffCharactor = staffCharactor;
    }
    public Date getStartDate() {
        return startDate;
    }
    public void setStartDate(Date startDate) {
        this.startDate = startDate;
    }
    public Date getEndDate() {
        return endDate;
    }
    public void setEndDate(Date endDate) {
        this.endDate = endDate;
    }
    public String getStaffTel() {
        return staffTel;
    }
    public void setStaffTel(String staffTel) {
        this.staffTel = staffTel;
    }
    public String getStaffSex() {
        return staffSex;
    }
    public void setStaffSex(String staffSex) {
        this.staffSex = staffSex;
    }
    public String getStaffPass() {
        return staffPass;
    }
    public void setStaffPass(String staffPass) {
        this.staffPass = staffPass;
    }
    public Date getPassEndDate() {
        return passEndDate;
    }
    public void setPassEndDate(Date passEndDate) {
        this.passEndDate = passEndDate;
    }
    public String getLoginFlg() {
        return loginFlg;
    }
    public void setLoginFlg(String loginFlg) {
        this.loginFlg = loginFlg;
    }
    @Override
    public String toString() {
        return "User [id=" + id + ", staffId=" + staffId + ", staffName=" + staffName + ", staffLoginName="
                + staffLoginName + ", staffCharactor=" + staffCharactor + ", startDate=" + startDate + ", endDate="
                + endDate + ", staffTel=" + staffTel + ", staffSex=" + staffSex + ", staffPass=" + staffPass
                + ", passEndDate=" + passEndDate + ", loginFlg=" + loginFlg + "]";
    }




}

这表没什么特别的，关键是customer表实体类：

package com.pms.projectsys.pojo;
import java.util.Date;

import javax.persistence.CascadeType;
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.OneToOne;
import javax.persistence.SequenceGenerator;
import javax.persistence.Table;

import org.springframework.format.annotation.DateTimeFormat;

import com.fasterxml.jackson.annotation.JsonFormat;
import com.pms.login.pojo.User;
@Entity
@Table(name="MAPS_MST_PJ_CUSTOMER")
@SequenceGenerator (name = "CUSTOMER_SEQ", sequenceName = "MAPS_MST_PJ_CUSTOMER_SEQ", allocationSize = 1) 
public class Customer {

    //客户ID
    @Id  
    @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "CUSTOMER_SEQ") 
    @Column(name = "CUSTOMER_ID")  
    private Integer customerId;
    //客户名称
    @Column(name="CUSTOMER_NAME")
    private String customerName;
    //创建时间
    @Column(name="CREATION_TIME")
    @DateTimeFormat(pattern = "yyyy-MM-dd HH:mm:ss")
    @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss", timezone = "GMT+8")
    private Date creationTime;
    //创建人ID
    @Column(name="CREATION_USER_ID",updatable=false)
    private Integer creationUserId;
    //修改时间
    @Column(name="MODIFIED_TIME")
    @DateTimeFormat(pattern = "yyyy-MM-dd HH:mm:ss")
    @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss", timezone = "GMT+8")
    private Date modifiedTime;
    //修改人ID
    @Column(name="MODIFIED_USER_ID")
    private Integer modifiedUserId;

    @OneToOne(optional = true, cascade = CascadeType.ALL)  
    @JoinColumn(name = "creation_user_id",referencedColumnName="id",updatable=false,insertable=false) 
    private User creationUser;


    public User getCreationUser() {
        return creationUser;
    }

    public void setCreationUser(User creationUser) {
        this.creationUser = creationUser;
    }

    @OneToOne(optional = true, cascade = CascadeType.ALL)  
    @JoinColumn(name = "modified_user_id",referencedColumnName="id",updatable=false,insertable=false) 
    private User modifiedUser;

    @javax.persistence.Transient
    private String creationUserName;

    public String getCreationUserName() {
        return creationUserName;
    }
    public void setCreationUserName(String creationUserName) {
        this.creationUserName = creationUserName;
    }
    @javax.persistence.Transient
    private String modifiedUserName;


    public String getModifiedUserName() {
        return modifiedUserName;
    }
    public void setModifiedUserName(String modifiedUserName) {
        this.modifiedUserName = modifiedUserName;
    }


    @Override
    public String toString() {
        return "Customer [customerId=" + customerId + ", customerName=" + customerName + ", creationTime="
                + creationTime + ", creationUserId=" + creationUserId + ", modifiedTime=" + modifiedTime
                + ", modifiedUserId=" + modifiedUserId + ", creationUser=" + creationUser + ", modifiedUser="
                + modifiedUser + ", creationUserName=" + creationUserName + ", modifiedUserName=" + modifiedUserName
                + "]";
    }

    public Customer(){

    }

    public Customer(Integer customerId, String customerName, User creationUser,  Date creationTime,
            User modifiedUser,Date modifiedTime) {
        super();
        this.customerId = customerId;
        this.customerName = customerName;
        this.creationTime = creationTime;
        this.modifiedTime = modifiedTime;
        this.creationUserId=creationUser.getId();
        this.modifiedUserId=modifiedUser.getId();
        this.creationUserName=creationUser.getStaffName();
        this.modifiedUserName=modifiedUser.getStaffName();
    }


    public User getModifiedUser() {
        return modifiedUser;
    }

    public void setModifiedUser(User modifiedUser) {
        this.modifiedUser = modifiedUser;
    }

    public Integer getCustomerId() {
        return customerId;
    }

    public void setCustomerId(Integer customerId) {
        this.customerId = customerId;
    }

    public String getCustomerName() {
        return customerName;
    }

    public void setCustomerName(String customerName) {
        this.customerName = customerName;
    }

    public Date getCreationTime() {

        return creationTime;
    }

    public void setCreationTime(Date creationTime) {
        this.creationTime = creationTime;
    }


    public Integer getCreationUserId() {
        return creationUserId;
    }

    public void setCreationUserId(Integer creationUserId) {
        this.creationUserId = creationUserId;
    }

    public Date getModifiedTime() {
        return modifiedTime;
    }

    public void setModifiedTime(Date modifiedTime) {
        this.modifiedTime = modifiedTime;
    }

    public Integer getModifiedUserId() {
        return modifiedUserId;
    }

    public void setModifiedUserId(Integer modifiedUserId) {
        this.modifiedUserId = modifiedUserId;
    }





}

在Customer实体类里面
增加一个Use类型的属性，

    @OneToOne(optional = true, cascade = CascadeType.ALL)  
    @JoinColumn(name = "creation_user_id",referencedColumnName="id",updatable=false,insertable=false) 
    private User creationUser;

在属性上加上OneToOne注解，并且指明两个实体类表以哪个字段关联起来的，

@JoinColumn(name = "creation_user_id",referencedColumnName="id",updatable=false,insertable=false) 

@JoinColumn这个注解属性里面：
name指向Customer对应的表里面所要关联的字段
referencedColumnName指向User对应的表，里面所要关联的字段
这样就把两张表通过字段关联起来了