Mybatis环境搭建及测试

1、新建java project，导入相应jar包

本次使用到的mybatis-3.2.7版本

mybatis需要jar包：mybatis-3.2.7.jar、lib文件下的依赖jar

mysql驱动jar包：mysql-connector-java-5.1.7.-bin.jar

2、创建数据库

数据库名：mybatis

数据表：user

3、配置mybaits核心配置文件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>
    <!-- 和spring整合后 environments配置将废除-->
    <environments default="development">
        <environment id="development">
            <!-- type="JDBC" 代表使用JDBC的提交和回滚来管理事务 -->
            <transactionManager type="JDBC" />
            
            <!-- mybatis提供了3种数据源类型，分别是：POOLED,UNPOOLED,JNDI -->
            <!-- POOLED 表示支持JDBC数据源连接池 -->
            <!-- UNPOOLED 表示不支持数据源连接池 -->
            <!-- JNDI 表示支持外部数据源连接池 -->
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.jdbc.Driver" />
                <property name="url" value="jdbc:mysql://localhost:3306/mybatis?characterEncoding=utf-8" />
                <property name="username" value="root" />
                <property name="password" value="mysqladmin" />
            </dataSource>
        
        </environment>
    </environments>
    
    <mappers>
        <mapper resource="User.xml"/>
    </mappers>
    
    
</configuration>

SqlMapConfig.xml放入项目中config源文件下

4、创建对应数据表的java实体类

User.java

package cn.itheima.pojo;

import java.util.Date;

public class User {
    private int id;
    private String username;// 用户姓名
    private String sex;// 性别
    private Date birthday;// 生日
    private String address;// 地址
    

    public int getId() {
        return id;
    }
    public void setId(int 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 + "]";
    } 

}

5、创建对应的映射文件

User.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">
<!-- namespace：命名空间，做sql隔离 -->
<mapper namespace="test">
    <!-- 
    id：sql语句唯一标识
    parameterType：指定传入参数类型（pojo类中对应的类型，不是数据库中的类型）
    resultType：返回结果集类型
    #{}：占位符，如果传入的类型是基本类型（string，long，double，int，boolean，float等），那么#{}中变量名称可以任意
     -->
    <select id="findUserById" parameterType="java.lang.Integer" resultType="cn.itheima.pojo.User">
        SELECT * FROM user WHERE id=#{id}
    </select>
    
    <!-- 
    如果返回的结果为集合，resultType中也是配置为集合中泛型的类型，即resultType="cn.itheima.pojo.User"
    ${}：拼接符，如果传入的类型是基本类型（string，long，double，int，boolean，float等），那么${}中变量名称必须是value
     -->
    <select id="findUserByUserName" parameterType="java.lang.String" resultType="cn.itheima.pojo.User">
        SELECT * FROM user WHERE username LIKE '%${value}%'
    </select>
    
    <!-- 
    如果传入的是pojo类型，则#{}中变量名称必须是pojo中对应的属性.属性.属性......
    如果要返回数据库自增主键，可以使用SELECT LAST_INSERT_ID()
     -->
    <insert id="insertUser" parameterType="cn.itheima.pojo.User">
        <!-- 执行SELECT LAST_INSERT_ID()数据库函数，返回自增的主键
            keyProperty：将返回的主键放入传入的参数的Id中保存（保存到user对象中的id属性）
            order：当前函数相对于insert语句的执行顺序，在insert前执行用BEFORE，在insert后执行用AFTER
            resultType：id的类型，也就是keyProperty中属性类型
         -->
        <selectKey keyProperty="id" order="AFTER" resultType="java.lang.Integer">
            SELECT LAST_INSERT_ID()
        </selectKey>
        INSERT INTO user (username,birthday,sex,address) VALUES (#{username},#{birthday},#{sex},#{address})
    </insert>
    
    <delete id="deleteUserById" parameterType="java.lang.Integer">
        DELETE FROM user WHERE id=#{id}
    </delete>
    
    <update id="updateUserById" parameterType="cn.itheima.pojo.User">
        UPDATE user SET  username=#{username} WHERE id=#{id}
    </update>
</mapper>

二、测试

package mybatis0523;

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

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 cn.itheima.pojo.User;

public class UserTest {

    @Test
    public void testFindUserById() throws Exception {
        String resource = "SqlMapConfig.xml";
        // 通过流将核心配置文件读取进来
        InputStream inputStream = Resources.getResourceAsStream(resource);
        // 通过核心配置文件创建会话工厂
        SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(inputStream);
        
        // 通过会话工厂创建会话
        SqlSession session = factory.openSession();
        
        User user = session.selectOne("test.findUserById", 1);
        System.out.println(user);
    }
    
    @Test
    public void testFindUserByUserName() throws Exception {
        String resource = "SqlMapConfig.xml";
        InputStream inputStream = Resources.getResourceAsStream(resource);
        SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(inputStream);
        
        SqlSession session = factory.openSession();
        List<User> list = session.selectList("test.findUserByUserName", "王");
        System.out.println(list);
    }
    
    @Test
    public void testInsertUser() throws Exception {
        String resource = "SqlMapConfig.xml";
        InputStream inputStream = Resources.getResourceAsStream(resource);
        SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(inputStream);
        
        SqlSession session = factory.openSession();
        User user = new User();
        user.setUsername("赵四");
        user.setBirthday(new Date());
        user.setSex("1");
        user.setAddress("北京昌平");
        System.out.println(user.getId());
        
        session.insert("test.insertUser", user);
        // mybatis中事务默认是开启的，所以在mybatis中不需要显式开启事务，只需要显式提交事务
        // 提交事务
        session.commit();
        System.out.println(user.getId());
    }
    
    @Test
    public void testDeleteUserById() throws Exception {
        String resource = "SqlMapConfig.xml";
        InputStream inputStream = Resources.getResourceAsStream(resource);
        SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(inputStream);
        
        SqlSession session = factory.openSession();
        session.delete("test.deleteUserById", 27);
        session.commit();
    }
    
    @Test
    public void testUpdateUserById() throws Exception {
        String resource = "SqlMapConfig.xml";
        InputStream inputStream = Resources.getResourceAsStream(resource);
        SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(inputStream);
        
        SqlSession session = factory.openSession();
        
        User user = new User();
        user.setUsername("赵四");
        user.setId(24);
        session.update("test.updateUserById", user);
        session.commit();
    }
}

简单的mybatis环境搭建和测试已完成，整个目录结构如下