Mybatis基础入门学习

Mybatis基础入门学习

mybatis架构分析

搭建测试mybatis架构

（1）下载并导入mybatis3.2.7.jar（架构），mysql-connector-java-5.1.7-bin.jar（数据库驱动），junit-4.9.jar（单元测试）

（2）测试mybatis项目搭建

（3）Jdbc资源文件

jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3307/mybatis?characterEncoding=utf-8
jdbc.username=root
jdbc.password=admins

（4）Mybatis核心配置文件

<?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>
    <!-- 数据库资源文件 -->
    <properties resource="jdbc.properties"/>

    <!-- 别名：方便映射文件调用 -->
    <typeAliases>
        <!-- 这个有弊端：有多少pojo就要配置多少个 -->
        <!--<typeAlias type="com.pojo.User" alias="user"/>-->
        <!-- 所以用包的方式：扫描该包及其子包的所有pojo，并取别名为（如:user或User） -->
        <package name="com.pojo"/>
    </typeAliases>

    <!-- 数据库环境,与Spring整合后，environments标签将废除-->
    <environments default="development">
        <environment id="development">
            <!-- 使用JDBC事务管理 -->
            <transactionManager type="JDBC"/>
            <!-- 数据库连接池 -->
            <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="admins"/>-->

                <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>

    <!-- 映射器的位置 -->
    <mappers>
        <!--<mapper resource="com/mapper/UserMapper.xml"/>-->
        <!-- 3个属性只能取一个，当为class时，xml文件和接口文件必须文件名一样且在同一个包下 -->
        <!--<mapper class="com.mapper.UserMapper"/>-->
        <!-- url:该属性指定mapper在盘符下的绝对路径，不建议使用 -->

        <!-- 上面的弊端还是会太多配置，导包的原则和class一样 -->
        <package name="com.mapper"/>
    </mappers>
</configuration>

（5）日志文件

#日志文件
log4j.rootLogger=DEBUG,stdout
log4j.logger.org.mybatis=DEBUG
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%5p %d %C: %m%n

（6）创建一个User类

package com.pojo;

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

/**
 * Serializable:序列化接口
 */
public class User implements Serializable {
    private static final long serialVersionUID = 1L;
    private Integer id;
    private String username;// 用户姓名
    private String sex;// 性别
    private Date birthday;// 生日
    private String address;// 地址

    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 getSex() {
        return sex;
    }
    public void setSex(String sex) {
        this.sex = sex;
    }
    public Date getBirthday() {
        return birthday;
    }
    public void setBirthday(Date birthday) {
        this.birthday = birthday;
    }
    public String getAddress() {
        return address;
    }
    public void setAddress(String address) {
        this.address = address;
    }
    @Override
    public String toString() {
        return "User [id=" + id + ", username=" + username + ", sex=" + sex
                + ", birthday=" + birthday + ", address=" + address + "]";
    }
}

（7）User类的映射器

<?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">
<!-- 命名空间：用于区分；如test.findUserById -->
<mapper namespace="com.mapper.UserMapper">
    <!-- 通过ID查询一个用户 -->
    <select id="findUserById" parameterType="Integer" resultType="User">
        <!-- #{}:表示占位符 -->
        select * from user where id=#{v}
    </select>

    <!-- 根据用户名模糊查询用户 -->
    <select id="findUserByName" parameterType="String" resultType="com.pojo.User">
        <!-- ${}:表示字符串拼接 -->
--         select * from user where username like '%${value}%'
        <!-- 防sql注入 -->
        select * from user where username like "%"#{value}"%"
    </select>

    <!-- 添加用户 -->
    <insert id="addUser" parameterType="com.pojo.User">
        <!-- 获取最新的ID主键 -->
        <selectKey keyProperty="id" resultType="Integer" order="AFTER">
          select LAST_INSERT_ID()
        </selectKey>
        insert into user (username,birthday,address,sex)
        values (#{username},#{birthday},#{address},#{sex})
    </insert>

    <!-- 更新用户 -->
    <update id="updateUserById" parameterType="com.pojo.User">
        update user
        set username=#{username},birthday=#{birthday},address=#{address},sex=#{sex}
        where id=#{id}
    </update>

    <!-- 删除用户 -->
    <delete id="delUserById" parameterType="Integer">
        delete from user where id=#{id}
    </delete>
</mapper>

（8）与映射器绑定的接口

package com.mapper;

import com.pojo.User;

/**
 * @author: XDZY
 * @date: 2018/8/30 10:02
 * @description: 实现用户增删改查的接口(映射器)
 * 遵循四个原则
 * 1）接口方法名与xml文件标签id一样
 * 2）方法返回值类型与xml文件一样
 * 3）方法的参数与xml文件一样
 * 4）xml文件命名空间与该接口绑定
 */
public interface UserMapper {
    public User findUserById(Integer id);
}

（9）测试mybatis实现增删改查

package com.junit;

import com.pojo.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.Test;

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

/**
 * @author: XDZY
 * @date: 2018/8/29 23:18
 * @description: 单元测试mybatis的增删改查
 */
public class UnitTest {
    //根据用户ID查询用户
    @Test
    public void testMybatis() throws Exception{
        //加载核心配置文件
        String resource="sqlMapConfig.xml";
        InputStream in= Resources.getResourceAsStream(resource);
        //创建sqlSessionFactory
        SqlSessionFactory sqlSessionFactory=new SqlSessionFactoryBuilder().build(in);
        //创建sqlSession
        SqlSession sqlSession=sqlSessionFactory.openSession();
        //执行sql语句
        User user=sqlSession.selectOne("com.mapper.UserMapper.findUserById",10);
        System.out.println(user);
    }

    //根据用户名模糊查询用户
    @Test
    public void testFindUserByName() throws Exception{
        //加载核心配置文件
        String resource="sqlMapConfig.xml";
        InputStream in= Resources.getResourceAsStream(resource);
        //创建sqlSessionFactory
        SqlSessionFactory sqlSessionFactory=new SqlSessionFactoryBuilder().build(in);
        //创建sqlSession
        SqlSession sqlSession=sqlSessionFactory.openSession();
        //执行sql语句
        List<User> users=sqlSession.selectList("com.mapper.UserMapper.findUserByName","五");
        for (User user:users){
            System.out.println(user);
        }
    }

    //添加用户
    @Test
    public void testAddUser() throws Exception{
        //加载核心配置文件
        String resource="sqlMapConfig.xml";
        InputStream in= Resources.getResourceAsStream(resource);
        //创建sqlSessionFactory
        SqlSessionFactory sqlSessionFactory=new SqlSessionFactoryBuilder().build(in);
        //创建sqlSession
        SqlSession sqlSession=sqlSessionFactory.openSession();
        //执行sql语句
        User user=new User();
        user.setUsername("judy");
        user.setSex("男");
        user.setBirthday(new Date());
        user.setAddress("珠海");
        int i=sqlSession.insert("com.mapper.UserMapper.addUser",user);
        //提交事务
        sqlSession.commit();
        System.out.println(user.getId());
    }

    //更新用户
    @Test
    public void testUpdateUserById() throws Exception{
        //加载核心配置文件
        String resource="sqlMapConfig.xml";
        InputStream in= Resources.getResourceAsStream(resource);
        //创建sqlSessionFactory
        SqlSessionFactory sqlSessionFactory=new SqlSessionFactoryBuilder().build(in);
        //创建sqlSession
        SqlSession sqlSession=sqlSessionFactory.openSession();
        //执行sql语句
        User user=new User();
        user.setId(28);
        user.setUsername("judy");
        user.setSex("女");
        user.setBirthday(new Date());
        user.setAddress("珠海");
        int i=sqlSession.update("com.mapper.UserMapper.updateUserById",user);
        //提交事务
        sqlSession.commit();
    }

    //删除用户
    @Test
    public void testDelUserById() throws Exception{
        //加载核心配置文件
        String resource="sqlMapConfig.xml";
        InputStream in= Resources.getResourceAsStream(resource);
        //创建sqlSessionFactory
        SqlSessionFactory sqlSessionFactory=new SqlSessionFactoryBuilder().build(in);
        //创建sqlSession
        SqlSession sqlSession=sqlSessionFactory.openSession();
        //执行sql语句
        sqlSession.delete("com.mapper.UserMapper.delUserById",28);
        //提交事务
        sqlSession.commit();
    }
}