Mybatis实现 CRUD 操作源码

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本文详细介绍了MyBatis框架的配置与使用，包括SqlMapConfig.xml的设置、环境配置、映射文件位置指定、DAO接口定义及其实现，以及如何进行用户数据的增删改查等常见操作。

基于代理dao

1.SqlMapConfig.xml

<?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>

    <!--配置properties
        可以在标签内部配置连接数据库的信息，也可以通过属性引用外部配置文件信息
        resource属性：
            用于指定配置文件的位置，是按照类路径的写法来写，并且必须存在于类路径下
        url属性：
            要求按照url的写法来写地址
            URL：Uniform Resource Locator 统一资源定位符y.它是可以唯一标识一个资源的位置
            写法：
                http://localhost:8080/mybatisserver/demo1Servlet
                协议      主机    端口      URI
            URI：Uniform Resource Identifier 统一资源标识符。它是在应用中可以唯一定位一个资源的
    -->
    <properties url="file:///E:/Study/ssm/MybatisCRUD/src/main/resources/jdbcConfig.properties">
        <!--<property name="driver" value="com.mysql.jdbc.Driver"/>
        <property name="url" value="jdbc:mysql://localhost:3306/mybatis?useUnicode=true&amp;characterEncoding=utf8"/>
        <property name="username" value="root"/>
        <property name="password" value="123"/>-->
    </properties>


    <!--使用typeAliases配置别名，它只能配置domain中类的别名-->
    <typeAliases>
        <!--typeAliases用于配置别名。type属性指定的是实体类全限定类名。alias属性指定别名
            当指定了别名就不再区分大小写
        -->
        <!--<typeAlias type="com.domain.User" alias="user"></typeAlias>-->


        <!--用于指定要配置别名的包。当指定之后。该包下的实体类都会注册别名。并且类名就是别名，不再区分大小写-->
        <package name="com.domain"></package>
    </typeAliases>

    <!--配置环境-->
    <environments default="mysql">
        <!--配置Mysql环境-->
        <environment id="mysql">
            <!--配置事务-->
            <transactionManager type="JDBC"></transactionManager>
            <!--配置连接池-->
            <dataSource type="POOLED">
                <property name="driver" value="${jdbc.driver}"/>
                <property name="url" value="${jdbc.url}"/>
                <property name="username" value="${jdbc.username}"/>
                <property name="password" value="${jdbc.password}"/>
            </dataSource>
        </environment>
    </environments>
    <!--配置映射文件的位置-->
    <mappers>
        <!--<mapper resource="com/dao/IUserDao.xml"/>-->

        <!--package标签是用于指定dao接口所在的包，当指定了之后就不需要在写mapper以及resource
            或者class了
        -->
        <package name="com.dao"></package>
    </mappers>
</configuration>

2.jdbcConfig.properties

jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/mybatis?useUnicode=true&characterEncoding=utf8
jdbc.username=root
jdbc.password=123

3.IUserDao.xml

<?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.dao.IUserDao">
    <!--配置查询结果的列名和实体类的属性名的对应关系-->
    <resultMap id="userMap" type="com.domain.User">
        <!--主键字段的对应-->
        <id property="userId" column="id"></id>
        <!--非主键字段的对应-->
        <result property="userName" column="username"></result>
        <result property="userAddress" column="address"></result>
        <result property="userSex" column="sex"></result>
        <result property="userBirthday" column="birthday"></result>
    </resultMap>
    <!--查询所有-->
    <select id="findAll" resultMap="userMap">
        <!--select id userId,username userName,address userAddress,sex userSex,birthday userBirthday from user;-->
        select * from user;
    </select>

    <!--保存用户-->
    <insert id="saveUser" parameterType="com.domain.User">
        <!--配置插入操作后，获取插入数据的id-->
        <selectKey keyProperty="userId" keyColumn="id" resultType="int" order="AFTER">
            select last_insert_id();
        </selectKey>
        insert into user(username,address,sex,birthday)values(#{userName},#{userAddress},#{userSex},#{userBirthday});
    </insert>
    <!--更新用户-->
    <update id="updateUser" parameterType="com.domain.User">
        UPDATE user set username=#{username},address=#{address},sex=#{sex},birthday=#{birthday} where id=#{id};
    </update>

    <!--删除用户-->
    <delete id="deleteUser" parameterType="java.lang.Integer">
        DELETE from user WHERE id=#{id};
    </delete>

    <!--根据id查询用户-->
    <select id="findById" parameterType="java.lang.Integer" resultType="com.domain.User">
        select * from user where id=#{id};
    </select>

    <!--根据名字模糊查询用户-->
    <select id="findByName" parameterType="java.lang.String" resultType="com.domain.User">
        <!-- select * from user where username like #{name}; -->
        select * from user where username like '%${value}%'
    </select>

    <!--查询总用户数-->
    <select id="findTotal" resultType="java.lang.Integer">
        select count(*) from user;
    </select>

    <!--配置queryVo的条件查询用户-->
    <select id="findUserByVo" parameterType="com.domain.QueryVo" resultType="com.domain.User">
        select * from user where username like #{user.username};
    </select>
</mapper>

4.IUser.dao

package com.dao;

import com.domain.QueryVo;
import com.domain.User;

import java.util.List;

//用户的持久层接口
public interface IUserDao {
    //查询所有用户
    List<User> findAll();

    //保存用户
    void saveUser(User user);

    //更新操作
    void updateUser(User user);

    //删除用户
    void deleteUser(Integer id);

    //根据id查询用户
    User findById(Integer id);

    //根据名称模糊查询
    List<User> findByName(String name);

    //查询总的用户数
    int findTotal();

    //根据queryVo中的条件查询用户
    User findUserByVo(QueryVo qureyVo);
}

4.User.java

package com.domain;

import java.io.Serializable;
import java.util.Date;

public class User implements Serializable{
    private Integer userId;
    private String userName;
    private String userAddress;
    private String userSex;
    private Date userBirthday;

    public Integer getUserId() {
        return userId;
    }

    public void setUserId(Integer userId) {
        this.userId = userId;
    }

    public String getUserName() {
        return userName;
    }

    public void setUserName(String userName) {
        this.userName = userName;
    }

    public String getUserAddress() {
        return userAddress;
    }

    public void setUserAddress(String userAddress) {
        this.userAddress = userAddress;
    }

    public String getUserSex() {
        return userSex;
    }

    public void setUserSex(String userSex) {
        this.userSex = userSex;
    }

    public Date getUserBirthday() {
        return userBirthday;
    }

    public void setUserBirthday(Date userBirthday) {
        this.userBirthday = userBirthday;
    }

    @Override
    public String toString() {
        return "User{" +
                "userId=" + userId +
                ", userName='" + userName + '\'' +
                ", userAddress='" + userAddress + '\'' +
                ", userSex='" + userSex + '\'' +
                ", userBirthday=" + userBirthday +
                '}';
    }
}

5.QueryVo.java

package com.domain;

public class QueryVo {

    private User user;

    public User getUser() {
        return user;
    }

    public void setUser(User user) {
        this.user = user;
    }
}

6.MybatisTest.java

package com.test;

import com.dao.IUserDao;
import com.domain.QueryVo;
import com.domain.User;
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.After;
import org.junit.Before;
import org.junit.Test;

import java.io.InputStream;
import java.util.Date;
import java.util.List;

public class MyBatisTest {
    private InputStream in;
    private SqlSession sqlSession;
    private IUserDao userDao;


    @Before //用于在测试方法执行之前执行
    public void init() throws Exception{
        //1.读取配置文件，生成字节输入流
        in = Resources.getResourceAsStream("SqlMapConfig.xml");
        //2.获取SQLSessionFactory对象
        SqlSessionFactoryBuilder builder = new SqlSessionFactoryBuilder();
        SqlSessionFactory factory = builder.build(in);
        //3.获取SqlSession对象
        sqlSession = factory.openSession();
        //4.获取dao的代理对象
        userDao = sqlSession.getMapper(IUserDao.class);
    }

    @After //用于在测试方法执行之后执行
    public void destory() throws Exception{
        //提交事务
        sqlSession.commit();
        //关闭资源
        sqlSession.close();
        in.close();
    }
    @Test
    public void testFindAll() throws Exception{
        //5.执行查询所有方法
        List<User> users = userDao.findAll();

        for(User user : users){
            System.out.println(user);
        }

    }

    //测试保存操作
    @Test
    public void testSave() throws Exception{
        User user = new User();
        user.setUserName("modify User");
        user.setUserAddress("重庆市永川区");
        user.setUserSex("男");
        user.setUserBirthday(new Date());
        System.out.println("保存前："+user);
        //5.执行保存方法
        userDao.saveUser(user);

        System.out.println("保存后："+user);
    }

    //测试更新操作
    @Test
    public void testUpdate() throws Exception{
        User user = new User();
        user.setUserId(51);
        user.setUserName("LEE");
        user.setUserAddress("北京市朝阳区");
        user.setUserSex("女");
        user.setUserBirthday(new Date());

        //5.执行更新方法
        userDao.updateUser(user);
    }

    //测试删除操作
    @Test
    public void testDelete() throws Exception{

        //5.执行删除方法
        userDao.deleteUser(52);
    }

    //测试根据id查询用户
    @Test
    public void testFindById() throws Exception{

        //5.执行根据id查用户方法
        User user = userDao.findById(48);
        System.out.println(user);
    }

    //测试根据名字模糊查询用户
    @Test
    public void testFindByName() throws Exception{

        //5.执行根据名字模糊查询用户方法
        //List<User> users = userDao.findByName("%王%");
        List<User> users = userDao.findByName("王");

        for(User user : users){
            System.out.println(user);
        }

    }

    //测试查询总的用户数
    @Test
    public void testFindTotal() throws Exception{

        //5.执行查询总的用户数的方法
        int total = userDao.findTotal();
        System.out.println(total);
    }

    //根据queryVo中的条件查询用户
    @Test
    public void testFindUserByVo() throws Exception{

        User user = new User();
        user.setUserName("modify User");
        user.setUserAddress("重庆市永川区");
        user.setUserSex("男");
        user.setUserBirthday(new Date());

        QueryVo queryVo = new QueryVo();
        queryVo.setUser(user);
        //5.执行查询总的用户数的方法
        User user1 = userDao.findUserByVo(queryVo);
        System.out.println(user1);
    }
}

传统Dao层开发

1.SqlMapConfig.xml

<?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>
    <!--配置环境-->
    <environments default="mysql">
        <!--配置Mysql环境-->
        <environment id="mysql">
            <!--配置事务-->
            <transactionManager type="JDBC"></transactionManager>
            <!--配置连接池-->
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.jdbc.Driver"/>
                <property name="url" value="jdbc:mysql://localhost:3306/mybatis?useUnicode=true&amp;characterEncoding=utf8"/>
                <property name="username" value="root"/>
                <property name="password" value="123"/>
            </dataSource>
        </environment>
    </environments>
    <!--配置映射文件的位置-->
    <mappers>
        <mapper resource="com/dao/IUserDao.xml"/>
    </mappers>
</configuration>

2.IUser.xml

<?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.dao.IUserDao">

    <!--查询所有-->
    <select id="findAll" resultType="com.domain.User">
        <!--select id userId,username userName,address userAddress,sex userSex,birthday userBirthday from user;-->
        select * from user;
    </select>

    <!--保存用户-->
    <insert id="saveUser" parameterType="com.domain.User">
        <!--配置插入操作后，获取插入数据的id-->
        <selectKey keyProperty="id" keyColumn="id" resultType="int" order="AFTER">
            select last_insert_id();
        </selectKey>
        insert into user(username,address,sex,birthday)values(#{username},#{address},#{sex},#{birthday});
    </insert>
    <!--更新用户-->
    <update id="updateUser" parameterType="com.domain.User">
        UPDATE user set username=#{username},address=#{address},sex=#{sex},birthday=#{birthday} where id=#{id};
    </update>

    <!--删除用户-->
    <delete id="deleteUser" parameterType="java.lang.Integer">
        DELETE from user WHERE id=#{id};
    </delete>

    <!--根据id查询用户-->
    <select id="findById" parameterType="java.lang.Integer" resultType="com.domain.User">
        select * from user where id=#{id};
    </select>

    <!--根据名字模糊查询用户-->
    <select id="findByName" parameterType="java.lang.String" resultType="com.domain.User">
        <!-- select * from user where username like #{name}; -->
        select * from user where username like '%${value}%'
    </select>

    <!--查询总用户数-->
    <select id="findTotal" resultType="java.lang.Integer">
        select count(*) from user;
    </select>
</mapper>

3.IUserDao.java

package com.dao;

import com.domain.User;

import java.util.List;

//用户的持久层接口
public interface IUserDao {
    //查询所有用户
    List<User> findAll();

    //保存用户
    void saveUser(User user);

    //更新操作
    void updateUser(User user);

    //删除用户
    void deleteUser(Integer id);

    //根据id查询用户
    User findById(Integer id);

    //根据名称模糊查询
    List<User> findByName(String name);

    //查询总的用户数
    int findTotal();

}

4.UserDaoImpl.java

package com.test;

import com.dao.IUserDao;
import com.dao.impl.UserDaoImpl;
import com.domain.User;
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.After;
import org.junit.Before;
import org.junit.Test;

import java.io.InputStream;
import java.util.Date;
import java.util.List;

public class MyBatisTest {
    private InputStream in;
    private SqlSession sqlSession;
    private IUserDao userDao;


    @Before //用于在测试方法执行之前执行
    public void init() throws Exception{
        //1.读取配置文件，生成字节输入流
        in = Resources.getResourceAsStream("SqlMapConfig.xml");
        //2.获取SQLSessionFactory对象
        SqlSessionFactoryBuilder builder = new SqlSessionFactoryBuilder();
        SqlSessionFactory factory = builder.build(in);
        //3.使用工厂对象，创建dao对象
        userDao = new UserDaoImpl(factory);
    }

    @After //用于在测试方法执行之后执行
    public void destory() throws Exception{
        in.close();
    }

    @Test
    public void testFindAll() throws Exception{
        //5.执行查询所有方法
        List<User> users = userDao.findAll();

        for(User user : users){
            System.out.println(user);
        }
    }

    //测试保存操作
    @Test
    public void testSave() throws Exception{
        User user = new User();
        user.setUsername("modify User");
        user.setAddress("重庆市永川区");
        user.setSex("男");
        user.setBirthday(new Date());
        System.out.println("保存前："+user);
        //5.执行保存方法
        userDao.saveUser(user);

        System.out.println("保存后："+user);
    }

    //测试更新操作
    @Test
    public void testUpdate() throws Exception{
        User user = new User();
        user.setId(54);
        user.setUsername("LEE");
        user.setAddress("北京市朝阳区");
        user.setSex("女");
        user.setBirthday(new Date());

        //5.执行更新方法
        userDao.updateUser(user);
    }

    //测试删除操作
    @Test
    public void testDelete() throws Exception{

        //5.执行删除方法
        userDao.deleteUser(57);
    }

    //测试根据id查询用户
    @Test
    public void testFindById() throws Exception{

        //5.执行根据id查用户方法
        User user = userDao.findById(48);
        System.out.println(user);
    }

    //测试根据名字模糊查询用户
    @Test
    public void testFindByName() throws Exception{

        //5.执行根据名字模糊查询用户方法
        //List<User> users = userDao.findByName("%王%");
        List<User> users = userDao.findByName("王");

        for(User user : users){
            System.out.println(user);
        }

    }

    //测试查询总的用户数
    @Test
    public void testFindTotal() throws Exception{

        //5.执行查询总的用户数的方法
        int total = userDao.findTotal();
        System.out.println(total);
    }
}

5.User.java

package com.domain;

import java.io.Serializable;
import java.util.Date;

public class User implements Serializable{
    private Integer id;
    private String username;
    private String address;
    private String sex;
    private Date birthday;

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getAddress() {
        return address;
    }

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

    public String getSex() {
        return sex;
    }

    public void setSex(String sex) {
        this.sex = sex;
    }

    public Date getBirthday() {
        return birthday;
    }

    public void setBirthday(Date birthday) {
        this.birthday = birthday;
    }

    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", username='" + username + '\'' +
                ", address='" + address + '\'' +
                ", sex='" + sex + '\'' +
                ", birthday=" + birthday +
                '}';
    }
}

6.MybatisTest.java

package com.test;

import com.dao.IUserDao;
import com.dao.impl.UserDaoImpl;
import com.domain.User;
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.After;
import org.junit.Before;
import org.junit.Test;

import java.io.InputStream;
import java.util.Date;
import java.util.List;

public class MyBatisTest {
    private InputStream in;
    private SqlSession sqlSession;
    private IUserDao userDao;


    @Before //用于在测试方法执行之前执行
    public void init() throws Exception{
        //1.读取配置文件，生成字节输入流
        in = Resources.getResourceAsStream("SqlMapConfig.xml");
        //2.获取SQLSessionFactory对象
        SqlSessionFactoryBuilder builder = new SqlSessionFactoryBuilder();
        SqlSessionFactory factory = builder.build(in);
        //3.使用工厂对象，创建dao对象
        userDao = new UserDaoImpl(factory);
    }

    @After //用于在测试方法执行之后执行
    public void destory() throws Exception{
        in.close();
    }

    @Test
    public void testFindAll() throws Exception{
        //5.执行查询所有方法
        List<User> users = userDao.findAll();

        for(User user : users){
            System.out.println(user);
        }
    }

    //测试保存操作
    @Test
    public void testSave() throws Exception{
        User user = new User();
        user.setUsername("modify User");
        user.setAddress("重庆市永川区");
        user.setSex("男");
        user.setBirthday(new Date());
        System.out.println("保存前："+user);
        //5.执行保存方法
        userDao.saveUser(user);

        System.out.println("保存后："+user);
    }

    //测试更新操作
    @Test
    public void testUpdate() throws Exception{
        User user = new User();
        user.setId(54);
        user.setUsername("LEE");
        user.setAddress("北京市朝阳区");
        user.setSex("女");
        user.setBirthday(new Date());

        //5.执行更新方法
        userDao.updateUser(user);
    }

    //测试删除操作
    @Test
    public void testDelete() throws Exception{

        //5.执行删除方法
        userDao.deleteUser(57);
    }

    //测试根据id查询用户
    @Test
    public void testFindById() throws Exception{

        //5.执行根据id查用户方法
        User user = userDao.findById(48);
        System.out.println(user);
    }

    //测试根据名字模糊查询用户
    @Test
    public void testFindByName() throws Exception{

        //5.执行根据名字模糊查询用户方法
        //List<User> users = userDao.findByName("%王%");
        List<User> users = userDao.findByName("王");

        for(User user : users){
            System.out.println(user);
        }

    }

    //测试查询总的用户数
    @Test
    public void testFindTotal() throws Exception{

        //5.执行查询总的用户数的方法
        int total = userDao.findTotal();
        System.out.println(total);
    }
}