Mybatis学习之一对多关系（五）

Mybatis学习一对多和反向一对一
内容：查询年级带学生和查询学生带年级

1.编写SqlSessionFactoryUtil类

package com.newbeedaly.util;

import java.io.InputStream;

import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;

public class SqlSessionFactoryUtil {

    private static SqlSessionFactory sqlSessionFactory;

    public static SqlSessionFactory getSqlSessionFactory(){
        if(sqlSessionFactory==null){
            InputStream inputStream=null;
            try{
                inputStream=Resources.getResourceAsStream("mybatis-config.xml");
                sqlSessionFactory=new SqlSessionFactoryBuilder().build(inputStream);
            }catch(Exception e){
                e.printStackTrace();
            }
        }
        return sqlSessionFactory;
    }

    public static SqlSession openSession(){
        return getSqlSessionFactory().openSession();
    }
}

2.编写学生类、年级类和地址类

package com.newbeedaly.model;

public class Student {

    private Integer id;
    private String name;
    private Integer age;
    private Address address;
    private Grade grade;


    public Student() {
        super();
        // TODO Auto-generated constructor stub
    }




    public Student(Integer id, String name, Integer age) {
        super();
        this.id = id;
        this.name = name;
        this.age = age;
    }




    public Student(String name, Integer age) {
        super();
        this.name = name;
        this.age = age;
    }



    public Integer getId() {
        return id;
    }
    public void setId(Integer id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public Integer getAge() {
        return age;
    }
    public void setAge(Integer age) {
        this.age = age;
    }
    public Address getAddress() {
        return address;
    }


    public void setAddress(Address address) {
        this.address = address;
    }


    public Grade getGrade() {
        return grade;
    }

    public void setGrade(Grade grade) {
        this.grade = grade;
    }




    @Override
    public String toString() {
        return "Student [id=" + id + ", name=" + name + ", age=" + age
                + ", address=" + address + ", grade=" + grade + "]";
    }


}

package com.newbeedaly.model;

import java.util.List;

public class Grade {

    private Integer id;
    private String gradeName;
    private List<Student> students;

    public Integer getId() {
        return id;
    }
    public void setId(Integer id) {
        this.id = id;
    }
    public String getGradeName() {
        return gradeName;
    }
    public void setGradeName(String gradeName) {
        this.gradeName = gradeName;
    }
    public List<Student> getStudents() {
        return students;
    }
    public void setStudents(List<Student> students) {
        this.students = students;
    }
    @Override
    public String toString() {
        return "Grade [id=" + id + ", gradeName=" + gradeName +"]";
    }


}

package com.newbeedaly.model;

public class Address {

    private Integer id;
    private String sheng;
    private String shi;
    private String qu;

    public Integer getId() {
        return id;
    }
    public void setId(Integer id) {
        this.id = id;
    }
    public String getSheng() {
        return sheng;
    }
    public void setSheng(String sheng) {
        this.sheng = sheng;
    }
    public String getShi() {
        return shi;
    }
    public void setShi(String shi) {
        this.shi = shi;
    }
    public String getQu() {
        return qu;
    }
    public void setQu(String qu) {
        this.qu = qu;
    }
    @Override
    public String toString() {
        return "Address [id=" + id + ", sheng=" + sheng + ", shi=" + shi
                + ", qu=" + qu + "]";
    }


}

3.编写配置文件log4j.properties，jdbc.properties，mybatis-config.xml

log4j.rootLogger=info,appender1,appender2

log4j.appender.appender1=org.apache.log4j.ConsoleAppender 

log4j.appender.appender2=org.apache.log4j.FileAppender 
log4j.appender.appender2.File=C:/logFile.txt

log4j.appender.appender1.layout=org.apache.log4j.TTCCLayout
log4j.appender.appender2.layout=org.apache.log4j.TTCCLayout  

jdbc.driverClassName=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/db_mybatis
jdbc.username=root
jdbc.password=123456

<?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="jdbc.properties"/> -->
    <properties>
        <property name="jdbc.driverClassName" value="com.mysql.jdbc.Driver"/>
        <property name="jdbc.url" value="jdbc:mysql://localhost:3306/db_mybatis"/>
        <property name="jdbc.username" value="root"/>
        <property name="jdbc.password" value="123456"/>
    </properties>
    <!-- <typeAliases>
        <typeAlias alias="Student" type="com.newbeedaly.model.Student"/>
    </typeAliases> -->
    <typeAliases>
        <package name="com.newbeedaly.model"/>
    </typeAliases>
    <environments default="development">
        <environment id="development">
            <transactionManager type="JDBC" />
            <dataSource type="POOLED">
                <property name="driver" value="${jdbc.driverClassName}" />
                <property name="url" value="${jdbc.url}" />
                <property name="username" value="${jdbc.username}" />
                <property name="password" value="${jdbc.password}" />
            </dataSource>
        </environment>
        <environment id="test">
            <transactionManager type="JDBC" />
            <dataSource type="POOLED">
                <property name="driver" value="${jdbc.driverClassName}" />
                <property name="url" value="${jdbc.url}" />
                <property name="username" value="${jdbc.username}" />
                <property name="password" value="${jdbc.password}" />
            </dataSource>
        </environment>
    </environments>
    <mappers>
        <!-- <mapper resource="com/newbeedaly/mappers/StudentMapper.xml" /> -->
        <!-- <mapper class="com.newbeedaly.mappers.StudentMapper"/> -->
        <package name="com.newbeedaly.mappers"/>
    </mappers>
</configuration>

4.编写GradeMapper.java和GradeMapper.xml以及学生和地址

package com.newbeedaly.mappers;

import com.newbeedaly.model.Grade;

public interface GradeMapper {

    public Grade findById(Integer id);

}

<?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.newbeedaly.mappers.GradeMapper">

    <resultMap type="Grade" id="GradeResult">
        <result property="id" column="id"/>
        <result property="gradeName" column="gradeName"/>
        <collection property="students" column="id" select="com.newbeedaly.mappers.StudentMapper.findByGradeId"></collection>
    </resultMap>

    <select id="findById" parameterType="Integer" resultMap="GradeResult">
        select * from t_grade where id=#{id}
    </select>

</mapper> 

package com.newbeedaly.mappers;

import java.util.List;

import com.newbeedaly.model.Student;

public interface StudentMapper {

    public int add(Student student);

    public int update(Student student);

    public int delete(Integer id);

    public Student findById(Integer id);

    public List<Student> find();

    public Student findStudentWithAddress(Integer id);

    public Student findByGradeId(Integer gradeId);
}

<?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.newbeedaly.mappers.StudentMapper">

    <!-- <resultMap type="Student" id="StudentResult">
        <id property="id" column="id"/>
        <result property="name" column="name"/>
        <result property="age" column="age"/>

        <result property="address.id" column="addressId"/>
        <result property="address.sheng" column="sheng"/>
        <result property="address.shi" column="shi"/>
        <result property="address.qu" column="qu"/>
    </resultMap> -->

    <!-- <resultMap type="Address" id="AddressResult">
        <result property="id" column="id"/>
        <result property="sheng" column="sheng"/>
        <result property="shi" column="shi"/>
        <result property="qu" column="qu"/>
    </resultMap>

    <resultMap type="Student" id="StudentResult">
        <id property="id" column="id"/>
        <result property="name" column="name"/>
        <result property="age" column="age"/>
        <association property="address" resultMap="AddressResult"/>
    </resultMap> -->

    <!-- <resultMap type="Student" id="StudentResult">
        <id property="id" column="id"/>
        <result property="name" column="name"/>
        <result property="age" column="age"/>
        <association property="address" javaType="Address">
            <result property="id" column="id"/>
            <result property="sheng" column="sheng"/>
            <result property="shi" column="shi"/>
            <result property="qu" column="qu"/>
        </association>
    </resultMap> -->

    <resultMap type="Student" id="StudentResult">
        <id property="id" column="id"/>
        <result property="name" column="name"/>
        <result property="age" column="age"/>
        <association property="address" column="addressId" select="com.newbeedaly.mappers.AddressMapper.findById"></association>
        <association property="grade" column="gradeId" select="com.newbeedaly.mappers.GradeMapper.findById"></association>
    </resultMap>

    <select id="findStudentWithAddress" resultMap="StudentResult" parameterType="Integer">
        select * from t_student t1,t_address t2 where t1.addressId=t2.id and t1.id=#{id}
    </select>

    <select id="findByGradeId" resultMap="StudentResult" parameterType="Integer">
        select * from t_student where gradeId=#{gradeId}
    </select>

    <insert id="add" parameterType="Student"  >
        insert into t_student values(null,#{name},#{age})
    </insert>

    <update id="update" parameterType="Student">
        update t_student set name=#{name},age=#{age} where id=#{id}
    </update>

    <delete id="delete" parameterType="Integer">
        delete from t_student where id=#{id}
    </delete>

    <select id="findById" parameterType="Integer" resultType="Student">
        select * from t_student where id=#{id}
    </select>

    <select id="find" resultMap="StudentResult">
        select * from t_student
    </select>
</mapper> 

package com.newbeedaly.mappers;

import com.newbeedaly.model.Address;

public interface AddressMapper {

    public Address findById(Integer id);

}

<?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.newbeedaly.mappers.AddressMapper">

    <resultMap type="Address" id="AddressResult">
        <result property="id" column="id"/>
        <result property="sheng" column="sheng"/>
        <result property="shi" column="shi"/>
        <result property="qu" column="qu"/>
    </resultMap>

    <select id="findById" parameterType="Integer" resultType="Address">
        select * from t_address where id=#{id}
    </select>

</mapper> 

5.编写测试类

package com.newbeedaly.service;


import org.apache.ibatis.session.SqlSession;
import org.apache.log4j.Logger;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;

import com.newbeedaly.mappers.GradeMapper;
import com.newbeedaly.model.Grade;
import com.newbeedaly.util.SqlSessionFactoryUtil;

public class GradeTest {

    private static Logger logger=Logger.getLogger(StudentTest.class);
    private SqlSession sqlSession=null;
    private GradeMapper gradeMapper=null;

    /**
     * 测试方法前调用
     * @throws Exception
     */
    @Before
    public void setUp() throws Exception {
        sqlSession=SqlSessionFactoryUtil.openSession();
        gradeMapper=sqlSession.getMapper(GradeMapper.class);
    }

    /**
     * 测试方法后调用
     * @throws Exception
     */
    @After
    public void tearDown() throws Exception {
        sqlSession.close();
    }

    @Test
    public void testFindGradeWithStudents() {
        logger.info("查询年级(带学生)");
        Grade grade=gradeMapper.findById(1);
        System.out.println(grade);
    }

}

package com.newbeedaly.service;


import org.apache.ibatis.session.SqlSession;
import org.apache.log4j.Logger;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;

import com.newbeedaly.mappers.StudentMapper;
import com.newbeedaly.model.Student;
import com.newbeedaly.util.SqlSessionFactoryUtil;

public class StudentTest3 {

    private static Logger logger=Logger.getLogger(StudentTest.class);
    private SqlSession sqlSession=null;
    private StudentMapper studentMapper=null;

    /**
     * 测试方法前调用
     * @throws Exception
     */
    @Before
    public void setUp() throws Exception {
        sqlSession=SqlSessionFactoryUtil.openSession();
        studentMapper=sqlSession.getMapper(StudentMapper.class);
    }

    /**
     * 测试方法后调用
     * @throws Exception
     */
    @After
    public void tearDown() throws Exception {
        sqlSession.close();
    }

    @Test
    public void testFindStudentWithAddress() {
        logger.info("查询学生(带地址)");
        Student student=studentMapper.findStudentWithAddress(3);
        System.out.println(student);
    }

    @Test
    public void testFindStudentWithGrade(){
        logger.info("查询学生(带年级)");
        Student student=studentMapper.findStudentWithAddress(1);
        System.out.println(student);
    }

}

package com.newbeedaly.service;

import org.apache.ibatis.session.SqlSession;
import org.apache.log4j.Logger;

import com.newbeedaly.mappers.StudentMapper;
import com.newbeedaly.model.Student;
import com.newbeedaly.util.SqlSessionFactoryUtil;

public class StudentTest {

    private static Logger logger=Logger.getLogger(StudentTest.class);

    public static void main(String[] args) {
        SqlSession sqlSession=SqlSessionFactoryUtil.openSession();
        StudentMapper studentMapper=sqlSession.getMapper(StudentMapper.class);
        Student student=new Student("李四",11);
        int result=studentMapper.add(student);
        sqlSession.commit();
        if(result>0){
            logger.info("添加成功！");
        }
    }
}

package com.newbeedaly.service;

import java.util.List;

import org.apache.ibatis.session.SqlSession;
import org.apache.log4j.Logger;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;

import com.newbeedaly.mappers.StudentMapper;
import com.newbeedaly.model.Student;
import com.newbeedaly.util.SqlSessionFactoryUtil;

public class StudentTest2 {

    private static Logger logger=Logger.getLogger(StudentTest.class);
    private SqlSession sqlSession=null;
    private StudentMapper studentMapper=null;

    /**
     * 测试方法前调用
     * @throws Exception
     */
    @Before
    public void setUp() throws Exception {
        sqlSession=SqlSessionFactoryUtil.openSession();
        studentMapper=sqlSession.getMapper(StudentMapper.class);
    }

    /**
     * 测试方法后调用
     * @throws Exception
     */
    @After
    public void tearDown() throws Exception {
        sqlSession.close();
    }

    @Test
    public void testAdd() {
        logger.info("添加学生");
        Student student=new Student("王五",12);
        studentMapper.add(student);
        sqlSession.commit();
    }

    @Test
    public void testUpdate(){
        logger.info("修改学生");
        Student student=new Student(8,"王五2",13);
        studentMapper.update(student);
        sqlSession.commit();
    }

    @Test
    public void testDelete(){
        logger.info("删除学生");
        studentMapper.delete(8);
        sqlSession.commit();
    }

    @Test
    public void testFindById(){
        logger.info("通过ID查找学生");
        Student student=studentMapper.findById(1);
        System.out.println(student);
    }

    @Test
    public void testFind(){
        logger.info("查找所有学生");
        List<Student> studentList=studentMapper.find();
        for(Student s:studentList){
            System.out.println(s);
        }
    }
}