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一蜕该、使用MyBatis對(duì)表執(zhí)行CRUD操作——基于XML的實(shí)現(xiàn)

1犁柜、定義sql映射xml文件

userMapper.xml文件的內(nèi)容如下：

<?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">
<!-- 為這個(gè)mapper指定一個(gè)唯一的namespace，namespace的值習(xí)慣上設(shè)置成包名+sql映射文件名堂淡，這樣就能夠保證namespace的值是唯一的
例如namespace="com.shi.mapping.userMapper"就是com.shi.mapping(包名)+userMapper(userMapper.xml文件去除后綴)
 -->
<mapper namespace="com.shi.mapping.userMapper">
    <!-- 在select標(biāo)簽中編寫查詢的SQL語句馋缅， 設(shè)置select標(biāo)簽的id屬性為getUser，id屬性值必須是唯一的绢淀，不能夠重復(fù)
    使用parameterType屬性指明查詢時(shí)使用的參數(shù)類型萤悴，resultType屬性指明查詢返回的結(jié)果集類型
    resultType="com.shi.mapping.User"就表示將查詢結(jié)果封裝成一個(gè)User類的對(duì)象返回
    User類就是users表所對(duì)應(yīng)的實(shí)體類
    -->
    <!--
        根據(jù)id查詢得到一個(gè)user對(duì)象
     -->
    <select id="getUser" parameterType="int"
            resultType="com.shi.mybatis.User">
        select * from users where id=#{id}
    </select>

    <!-- 創(chuàng)建用戶(Create) -->
    <insert id="addUser" parameterType="com.shi.mybatis.User">
        insert into users(name,age) values(#{name},#{age})
    </insert>

    <!-- 刪除用戶(Remove) -->
    <delete id="deleteUser" parameterType="int">
        delete from users where id=#{id}
    </delete>

    <!-- 修改用戶(Update) -->
    <update id="updateUser" parameterType="com.shi.mybatis.User">
        update users set name=#{name},age=#{age} where id=#{id}
    </update>

    <!-- 查詢?nèi)坑脩?->
    <select id="getAllUsers" resultType="com.shi.mybatis.User">
        select * from users
    </select>

</mapper>

單元測(cè)試類代碼如下：

package com.shi.mybatis;

import java.util.List;
import org.apache.ibatis.session.SqlSession;
import org.junit.Test;

public class TestCRUDByXmlMapper {

    @Test
    public void testAdd(){
        //SqlSession sqlSession = MyBatisUtil.getSqlSession(false);
        SqlSession sqlSession = MyBatisUtil.getSqlSession(true);
        /**
         * 映射sql的標(biāo)識(shí)字符串，
         * com.shi.mapping.userMapper是userMapper.xml文件中mapper標(biāo)簽的namespace屬性的值皆的，
         * addUser是insert標(biāo)簽的id屬性值覆履，通過insert標(biāo)簽的id屬性值就可以找到要執(zhí)行的SQL
         */
        String statement = "com.shi.mapping.userMapper.addUser";//映射sql的標(biāo)識(shí)字符串
        User user = new User();
        user.setName("用戶孤傲蒼狼");
        user.setAge(20);
        //執(zhí)行插入操作
        int retResult = sqlSession.insert(statement,user);
        //手動(dòng)提交事務(wù)
        //sqlSession.commit();
        //使用SqlSession執(zhí)行完SQL之后需要關(guān)閉SqlSession
        sqlSession.close();
        System.out.println(retResult);
    }

    @Test
    public void testUpdate(){
        SqlSession sqlSession = MyBatisUtil.getSqlSession(true);
        /**
         * 映射sql的標(biāo)識(shí)字符串，
         * com.shi.mapping.userMapper是userMapper.xml文件中mapper標(biāo)簽的namespace屬性的值费薄，
         * updateUser是update標(biāo)簽的id屬性值硝全，通過update標(biāo)簽的id屬性值就可以找到要執(zhí)行的SQL
         */
        String statement = "com.shi.mapping.userMapper.updateUser";//映射sql的標(biāo)識(shí)字符串
        User user = new User();
        user.setId(3);
        user.setName("孤傲蒼狼");
        user.setAge(25);
        //執(zhí)行修改操作
        int retResult = sqlSession.update(statement,user);
        //使用SqlSession執(zhí)行完SQL之后需要關(guān)閉SqlSession
        sqlSession.close();
        System.out.println(retResult);
    }

    @Test
    public void testDelete(){
        SqlSession sqlSession = MyBatisUtil.getSqlSession(true);
        /**
         * 映射sql的標(biāo)識(shí)字符串，
         * com.shi.mapping.userMapper是userMapper.xml文件中mapper標(biāo)簽的namespace屬性的值义锥，
         * deleteUser是delete標(biāo)簽的id屬性值柳沙，通過delete標(biāo)簽的id屬性值就可以找到要執(zhí)行的SQL
         */
        String statement = "com.shi.mapping.userMapper.deleteUser";//映射sql的標(biāo)識(shí)字符串
        //執(zhí)行刪除操作
        int retResult = sqlSession.delete(statement,5);
        //使用SqlSession執(zhí)行完SQL之后需要關(guān)閉SqlSession
        sqlSession.close();
        System.out.println(retResult);
    }

    @Test
    public void testGetAll(){
        SqlSession sqlSession = MyBatisUtil.getSqlSession();
        /**
         * 映射sql的標(biāo)識(shí)字符串，
         * com.shi.mapping.userMapper是userMapper.xml文件中mapper標(biāo)簽的namespace屬性的值拌倍，
         * getAllUsers是select標(biāo)簽的id屬性值赂鲤，通過select標(biāo)簽的id屬性值就可以找到要執(zhí)行的SQL
         */
        String statement = "com.shi.mapping.userMapper.getAllUsers";//映射sql的標(biāo)識(shí)字符串
        //執(zhí)行查詢操作，將查詢結(jié)果自動(dòng)封裝成List<User>返回
        List<User> lstUsers = sqlSession.selectList(statement);
        //使用SqlSession執(zhí)行完SQL之后需要關(guān)閉SqlSession
        sqlSession.close();
        System.out.println(lstUsers);
    }
}

二柱恤、使用MyBatis對(duì)表執(zhí)行CRUD操作——基于注解的實(shí)現(xiàn)

• 1数初、定義sql映射的接口

UserMapperI接口的代碼如下：

package com.shi.mapping;

import java.util.List;

import com.shi.mybatis.User;
import org.apache.ibatis.annotations.Delete;
import org.apache.ibatis.annotations.Insert;
import org.apache.ibatis.annotations.Select;
import org.apache.ibatis.annotations.Update;

/**
 * @author AFinalStone
 * 定義sql映射的接口，使用注解指明方法要執(zhí)行的SQL
 */
public interface UserMapperI {

    //使用@Insert注解指明add方法要執(zhí)行的SQL
    @Insert("insert into users(name, age) values(#{name}, #{age})")
    public int add(User user);
    
    //使用@Delete注解指明deleteById方法要執(zhí)行的SQL
    @Delete("delete from users where id=#{id}")
    public int deleteById(int id);
    
    //使用@Update注解指明update方法要執(zhí)行的SQL
    @Update("update users set name=#{name},age=#{age} where id=#{id}")
    public int update(User user);
    
    //使用@Select注解指明getById方法要執(zhí)行的SQL
    @Select("select * from users where id=#{id}")
    public User getById(int id);
    
    //使用@Select注解指明getAll方法要執(zhí)行的SQL
    @Select("select * from users")
    public List<User> getAll();
}

需要說明的是梗顺，我們不需要針對(duì)UserMapperI接口去編寫具體的實(shí)現(xiàn)類代碼泡孩，這個(gè)具體的實(shí)現(xiàn)類由MyBatis幫我們動(dòng)態(tài)構(gòu)建出來，我們只需要直接拿來使用即可寺谤。

• 2仑鸥、在conf.xml文件中注冊(cè)這個(gè)映射接口

<?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>
    <environments default="development">
        <environment id="development">
            <transactionManager type="JDBC" />
            <!-- 配置數(shù)據(jù)庫連接信息 -->
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.jdbc.Driver" />
                <property name="url" value="jdbc:mysql://localhost:3306/mybatis" />
                <property name="username" value="root" />
                <property name="password" value="123456" />
            </dataSource>
        </environment>
    </environments>


    <mappers>
        <!-- 注冊(cè)u(píng)serMapper.xml文件，
        userMapper.xml位于com.shi.mapping這個(gè)包下变屁，所以resource寫成com/shi/mapping/userMapper.xml-->
        <mapper resource="com/shi/mapping/userMapper.xml"/>
        <!-- 注冊(cè)UserMapper映射接口-->
        <mapper class="com.shi.mapping.UserMapperI"/>
    </mappers>

</configuration>

單元測(cè)試類的代碼如下：

package com.shi.mybatis;

import java.util.List;

import com.shi.mapping.UserMapperI;
import org.apache.ibatis.session.SqlSession;
import org.junit.Test;

public class TestCRUDByAnnotationMapper {

    @Test
    public void testAdd(){
        SqlSession sqlSession = MyBatisUtil.getSqlSession(true);
        //得到UserMapperI接口的實(shí)現(xiàn)類對(duì)象眼俊，UserMapperI接口的實(shí)現(xiàn)類對(duì)象由sqlSession.getMapper(UserMapperI.class)動(dòng)態(tài)構(gòu)建出來
        UserMapperI mapper = sqlSession.getMapper(UserMapperI.class);
        User user = new User();
        user.setName("用戶xdp");
        user.setAge(20);
        int add = mapper.add(user);
        //使用SqlSession執(zhí)行完SQL之后需要關(guān)閉SqlSession
        sqlSession.close();
        System.out.println(add);
    }
    
    @Test
    public void testUpdate(){
        SqlSession sqlSession = MyBatisUtil.getSqlSession(true);
        //得到UserMapperI接口的實(shí)現(xiàn)類對(duì)象，UserMapperI接口的實(shí)現(xiàn)類對(duì)象由sqlSession.getMapper(UserMapperI.class)動(dòng)態(tài)構(gòu)建出來
        UserMapperI mapper = sqlSession.getMapper(UserMapperI.class);
        User user = new User();
        user.setId(3);
        user.setName("孤傲蒼狼_xdp");
        user.setAge(26);
        //執(zhí)行修改操作
        int retResult = mapper.update(user);
        //使用SqlSession執(zhí)行完SQL之后需要關(guān)閉SqlSession
        sqlSession.close();
        System.out.println(retResult);
    }
    
    @Test
    public void testDelete(){
        SqlSession sqlSession = MyBatisUtil.getSqlSession(true);
        //得到UserMapperI接口的實(shí)現(xiàn)類對(duì)象粟关，UserMapperI接口的實(shí)現(xiàn)類對(duì)象由sqlSession.getMapper(UserMapperI.class)動(dòng)態(tài)構(gòu)建出來
        UserMapperI mapper = sqlSession.getMapper(UserMapperI.class);
        //執(zhí)行刪除操作
        int retResult = mapper.deleteById(7);
        //使用SqlSession執(zhí)行完SQL之后需要關(guān)閉SqlSession
        sqlSession.close();
        System.out.println(retResult);
    }
    
    @Test
    public void testGetUser(){
        SqlSession sqlSession = MyBatisUtil.getSqlSession();
        //得到UserMapperI接口的實(shí)現(xiàn)類對(duì)象疮胖，UserMapperI接口的實(shí)現(xiàn)類對(duì)象由sqlSession.getMapper(UserMapperI.class)動(dòng)態(tài)構(gòu)建出來
        UserMapperI mapper = sqlSession.getMapper(UserMapperI.class);
        //執(zhí)行查詢操作，將查詢結(jié)果自動(dòng)封裝成User返回
        User user = mapper.getById(8);
        //使用SqlSession執(zhí)行完SQL之后需要關(guān)閉SqlSession
        sqlSession.close();
        System.out.println(user);
    }
    
    @Test
    public void testGetAll(){
        SqlSession sqlSession = MyBatisUtil.getSqlSession();
        //得到UserMapperI接口的實(shí)現(xiàn)類對(duì)象，UserMapperI接口的實(shí)現(xiàn)類對(duì)象由sqlSession.getMapper(UserMapperI.class)動(dòng)態(tài)構(gòu)建出來
        UserMapperI mapper = sqlSession.getMapper(UserMapperI.class);
        //執(zhí)行查詢操作澎灸，將查詢結(jié)果自動(dòng)封裝成List<User>返回
        List<User> lstUsers = mapper.getAll();
        //使用SqlSession執(zhí)行完SQL之后需要關(guān)閉SqlSession
        sqlSession.close();
        System.out.println(lstUsers);
    }
}

用到的MyBatisUtil工具類代碼如下：

package com.shi.mybatis;

import java.io.InputStream;

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

public class MyBatisUtil {

    /**
     * 獲取SqlSessionFactory
     * @return SqlSessionFactory
     */
    public static SqlSessionFactory getSqlSessionFactory() {
        String resource = "conf.xml";
        InputStream is = MyBatisUtil.class.getClassLoader().getResourceAsStream(resource);
        SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(is);
        return factory;
    }
    
    /**
     * 獲取SqlSession
     * @return SqlSession
     */
    public static SqlSession getSqlSession() {
        return getSqlSessionFactory().openSession();
    }
    
    /**
     * 獲取SqlSession
     * @param isAutoCommit 
     *         true 表示創(chuàng)建的SqlSession對(duì)象在執(zhí)行完SQL之后會(huì)自動(dòng)提交事務(wù)
     *         false 表示創(chuàng)建的SqlSession對(duì)象在執(zhí)行完SQL之后不會(huì)自動(dòng)提交事務(wù)院塞，這時(shí)就需要我們手動(dòng)調(diào)用sqlSession.commit()提交事務(wù)
     * @return SqlSession
     */
    public static SqlSession getSqlSession(boolean isAutoCommit) {
        return getSqlSessionFactory().openSession(isAutoCommit);
    }
}

以上的相關(guān)代碼是全部測(cè)試通過的，關(guān)于使用MyBatis對(duì)表執(zhí)行CRUD操作的內(nèi)容就這么多性昭。

項(xiàng)目地址:傳送門