Mybatis（7）：返回结果封装ResulMap的高级属性--Collection标签

本文链接：https://blog.youkuaiyun.com/qq_29166327/article/details/78826739

本文介绍如何使用MyBatis实现Java实体类中的集合属性映射，包括创建实体类、定义Mapper接口、配置SQL映射文件及单元测试。

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四部曲：

1.写接口 + 2.写映射sql + 3.把mapper注册到mybatis的配置文件 + 4.写单元测试和运行

（1）新建两个实体类User.java 和 Address.java：
User.java（必须包含一个复杂属性（eg：序列），因为我们将通过Collection对嵌入的 javaBean 进行映射）：

User.java：

package com.smbms.entities;

import java.util.Date;
import java.util.List;

public class User {
	private Integer id;
	private String userCode;
	private String userName;
	private String userPassword;
	private Integer gender;
	private Date birthday;
	private String phone;
	private String address ;
	private Integer userRole;
	private Integer createdBy;
	private Date creationDate;
	private Integer modifyBy;
	private Date modifyDate;
	private String userRoleName;
	private List<Address> addressList;
	
	
		
	public List<Address> getAddressList() {
		return addressList;
	}
	public void setAddressList(List<Address> addressList) {
		this.addressList = addressList;
	}
	public String getUserRoleName() {
		return userRoleName;
	}
	public void setUserRoleName(String userRoleName) {
		this.userRoleName = userRoleName;
	}
	public Integer getId() {
		return id;
	}
	public void setId(Integer id) {
		this.id = id;
	}
	public String getUserCode() {
		return userCode;
	}
	public void setUserCode(String userCode) {
		this.userCode = userCode;
	}
	public String getUserName() {
		return userName;
	}
	public void setUserName(String userName) {
		this.userName = userName;
	}
	public String getUserPassword() {
		return userPassword;
	}
	public void setUserPassword(String userPassword) {
		this.userPassword = userPassword;
	}
	public Integer getGender() {
		return gender;
	}
	public void setGender(Integer gender) {
		this.gender = gender;
	}
	public Date getBirthday() {
		return birthday;
	}
	public void setBirthday(Date birthday) {
		this.birthday = birthday;
	}
	public String getPhone() {
		return phone;
	}
	public void setPhone(String phone) {
		this.phone = phone;
	}
	public String getAddress() {
		return address;
	}
	public void setAddress(String address) {
		this.address = address;
	}
	public Integer getUserRole() {
		return userRole;
	}
	public void setUserRole(Integer userRole) {
		this.userRole = userRole;
	}
	public Integer getCreatedBy() {
		return createdBy;
	}
	public void setCreatedBy(Integer createdBy) {
		this.createdBy = createdBy;
	}
	public Date getCreationDate() {
		return creationDate;
	}
	public void setCreationDate(Date creationDate) {
		this.creationDate = creationDate;
	}
	public Integer getModifyBy() {
		return modifyBy;
	}
	public void setModifyBy(Integer modifyBy) {
		this.modifyBy = modifyBy;
	}
	public Date getModifyDate() {
		return modifyDate;
	}
	public void setModifyDate(Date modifyDate) {
		this.modifyDate = modifyDate;
	}
	public User(Integer id, String userCode, String userName, String userPassword, Integer gender, Date birthday,
			String phone, String address, Integer userRole, Integer createdBy, Date creationDate, Integer modifyBy,
			Date modifyDate) {
		super();
		this.id = id;
		this.userCode = userCode;
		this.userName = userName;
		this.userPassword = userPassword;
		this.gender = gender;
		this.birthday = birthday;
		this.phone = phone;
		this.address = address;
		this.userRole = userRole;
		this.createdBy = createdBy;
		this.creationDate = creationDate;
		this.modifyBy = modifyBy;
		this.modifyDate = modifyDate;
	}
	public User() {
		super();
		// TODO 自动生成的构造函数存根
	}
	@Override
	public String toString() {
		return "User [id=" + id + ", userCode=" + userCode + ", userName=" + userName + ", userPassword=" + userPassword
				+ ", gender=" + gender + ", birthday=" + birthday + ", phone=" + phone + ", address=" + address
				+ ", userRole=" + userRole + ", createdBy=" + createdBy + ", creationDate=" + creationDate
				+ ", modifyBy=" + modifyBy + ", modifyDate=" + modifyDate + "]";
	}
	
}

Address.java：

package com.smbms.entities;

import java.util.Date;

public class Address {
	private Integer id;
	private String postCode;
	private String contact;
	private String tel;
	private Integer createBy;
	private Date creationDate;
	private String modify;
	private Date modifyDate;
	private String AddressDesc;
	
	
	public String getAddressDesc() {
		return AddressDesc;
	}
	public void setAddressDesc(String addressDesc) {
		AddressDesc = addressDesc;
	}
	public Integer getId() {
		return id;
	}
	public void setId(Integer id) {
		this.id = id;
	}
	public String getPostCode() {
		return postCode;
	}
	public void setPostCode(String postCode) {
		this.postCode = postCode;
	}
	public String getContact() {
		return contact;
	}
	public void setContact(String contact) {
		this.contact = contact;
	}
	public String getTel() {
		return tel;
	}
	public void setTel(String tel) {
		this.tel = tel;
	}
	public Integer getCreateBy() {
		return createBy;
	}
	public void setCreateBy(Integer createBy) {
		this.createBy = createBy;
	}
	public Date getCreationDate() {
		return creationDate;
	}
	public void setCreationDate(Date creationDate) {
		this.creationDate = creationDate;
	}
	public String getModify() {
		return modify;
	}
	public void setModify(String modify) {
		this.modify = modify;
	}
	public Date getModifyDate() {
		return modifyDate;
	}
	public void setModifyDate(Date modifyDate) {
		this.modifyDate = modifyDate;
	}
	@Override
	public String toString() {
		return "Address [id=" + id + ", postCode=" + postCode + ", contact=" + contact + ", tel=" + tel + ", createBy="
				+ createBy + ", creationDate=" + creationDate + ", modify=" + modify + ", modifyDate=" + modifyDate
				+ "]";
	}
	public Address(Integer id, String postCode, String contact, String tel, Integer createBy, Date creationDate,
			String modify, Date modifyDate) {
		super();
		this.id = id;
		this.postCode = postCode;
		this.contact = contact;
		this.tel = tel;
		this.createBy = createBy;
		this.creationDate = creationDate;
		this.modify = modify;
		this.modifyDate = modifyDate;
	}
	public Address() {
		super();
		// TODO 自动生成的构造函数存根
	}
	
}

（2）在接口类UserMapper.java中进行方法定义：

package com.smbms.dao;

import java.util.List;
import java.util.Map;

import org.apache.ibatis.annotations.Param;

import com.smbms.entities.User;

public interface UserMapper {
	
	public List<User> getAddressListByUserId(@Param("id") Integer userId);
	
}

（3）在sql映射文件 UserMapper.xml 完成配置：

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper
 PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
 "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
 <mapper namespace="com.smbms.dao.UserMapper">

	<resultMap type="com.smbms.entities.User" id="UserAdressResult">
		<id property="id" column="id"/>
		<result property="userCode" column="userCode"/>
		<result property="userName" column="userName"/>
		<collection property="addressList" ofType="com.smbms.entities.Address">
			<id property="id" column="a_id"/>
			<result property="postCode" column="postCode"/>
			<result property="tel" column="tel"/>
			<result property="contact" column="contact"/>
			<result property="addressDesc" column="addressDesc"/>		
		</collection>
	</resultMap>
	<select id="getAddressListByUserId" 
	     parameterType="Integer" resultMap="UserAdressResult">
		select u.* , a.id as a_id ,a.contact,a.addressDesc,a.tel,a.postCode
		from smbms_user u,smbms_address a
		   where u.userRole=#{UserRole} and u.userRole=r.id
	</select>
	
 </mapper>

（4）在全局配置文件注册映射文件：

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE configuration
 PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
 "http://mybatis.org/dtd/mybatis-3-config.dtd" >
 <configuration>
 	<properties resource="datasources.properties"/>
 	<settings>
 		<setting name="logImpl" value="LOG4J"/>
 	</settings>
 	<environments default="development">
 		<environment id="development">
 			<transactionManager type="JDBC"></transactionManager>
 			<dataSource type="POOLED">
				<property name="driver" value="${jdbc.driver}"/>
				<property name="url" value="${jdbc.url}"/>
				<property name="username" value="${jdbc.usename}"/>
				<property name="password" value="${jdbc.password}"/>
			</dataSource>
 		</environment>
 	</environments>
 	<mappers>
 		<mapper resource="com/smbms/dao/UserMapper.xml"/>
 		<mapper resource="com/smbms/dao/ProviderMapper.xml"/>
 	</mappers>
 </configuration>

（5）编写单元测试UserTest：

package com.smbms.entities;

import java.io.IOException;
import java.io.InputStream;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Date;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.apache.ibatis.annotations.Param;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import org.junit.Test;

import com.smbms.dao.ProviderMapper;
import com.smbms.dao.UserMapper;

public class UserTest {
	
	public SqlSession getSqlSession() throws IOException{
		String resource = "mybatis-config.xml";
		InputStream inputStream = Resources.getResourceAsStream(resource);
		SqlSessionFactory build = new SqlSessionFactoryBuilder().build(inputStream);
		SqlSession openSession = build.openSession();
		return openSession;
	}
	//collection标签对应于User的一个对象属性的列表
	@Test
	public void test12() throws IOException{
		System.out.println("===============test add!");
		List<User> userlist = new ArrayList<User> ();
		User user = new User();
		int count = 0;
		SqlSession sqlSession = getSqlSession();
		UserMapper mapper = sqlSession.getMapper(UserMapper.class);
		try{
			userlist = mapper.getAddressListByUserId(4);
			for(User u: userlist){
				List<Address> addressList = u.getAddressList();
				for(Address a:addressList){
					System.out.println("***"+a.getId()+a.getContact()+a.getModify()+a.getPostCode()+a.getTel()+a.getCreateBy()+a.getCreationDate());
					System.out.println(a.toString());
					System.out.println("================test end");
				}
			}
		}catch(Exception e){
			e.printStackTrace();
			sqlSession.rollback();
		}finally{
			sqlSession.close();
		}
	}

}

综上，完成一个返回结果封装ResulMap的高级属性--Collection标签的Demo。