01.MyBatis快速入门

1.下载jar包

Mybatis包+数据库驱动包

https://github.com/mybatis/mybatis-3/releases

2.新建Java工程并导入jar包

3.创建数据库与表

CREATE DATABSE mybatis01;
USE mybatis01;

SET FOREIGN_KEY_CHECKS=0;

DROP TABLE IF EXISTS `user`;
CREATE TABLE `user` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `username` varchar(32) NOT NULL COMMENT '用户名称',
  `birthday` date DEFAULT NULL COMMENT '生日',
  `sex` char(1) DEFAULT NULL COMMENT '性别',
  `address` varchar(256) DEFAULT NULL COMMENT '地址',
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=27 DEFAULT CHARSET=utf8;

INSERT INTO `user` VALUES ('1', '王五', null, '2', null);
INSERT INTO `user` VALUES ('10', '张三', '2014-07-10', '1', '北京市');
INSERT INTO `user` VALUES ('16', '张小明', null, '1', '河南郑州');
INSERT INTO `user` VALUES ('22', '陈小明', null, '1', '河南郑州');
INSERT INTO `user` VALUES ('24', '张三丰', null, '1', '河南郑州');
INSERT INTO `user` VALUES ('25', '陈小明', null, '1', '河南郑州');
INSERT INTO `user` VALUES ('26', '王五', null, null, null);

4.新建Mybatis核心配置文件+log4j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>
    <!-- 和spring整合后 environments配置将废除 -->
    <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/mybatis01?characterEncoding=utf-8" />
                <property name="username" value="root" />
                <property name="password" value="toor" />
            </dataSource>
        </environment>
    </environments>

</configuration>

# Global logging configuration
log4j.rootLogger=DEBUG, stdout
# Console output...
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%5p [%t] - %m%n

5.创建实体类和映射文件

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 + "]";
    }

}

<?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，用于隔离sql，还有一个很重要的作用，后面会讲 -->
<mapper namespace="test">

</mapper>

6.在SqlMalConfig.xml中配置映射文件

    <!-- 添加映射 -->
    <mappers>
        <mapper resource="cn/itcast/mybatis/po/User.xml"/>
    </mappers>

7.测试

1.查询一条结果

    <!-- 通过ID查询一个结果 -->
    <select id="findUserById" parameterType="int" resultType="cn.itcast.mybatis.po.User">
        select * from user where id = #{id}
    </select>

    /**
     * 通过ID查询一个结果
     * @throws Exception
     */
    @Test
    public void m01() throws Exception{

        //加载配置文件
        InputStream inputStream = Resources.getResourceAsStream("SqlMapConfig.xml");

        //获取SqlSessionFactory
        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);

        //获取SqlSession
        SqlSession sqlSession = sqlSessionFactory.openSession();

        //执行SQL
        User user = sqlSession.selectOne("test.findUserById", 10);

        System.out.println(user);
    }

2.通过用户名模糊查询

    <!-- 通过用户名模糊查询 -->
    <select id="findUserByUsername" parameterType="String" resultType="cn.itcast.mybatis.po.User">
        select * from user where username like "%"#{username}"%"　　　　　　<!-- SELECT * FROM `user` WHERE username LIKE '%${value}%' -->
    </select>

        //执行SQL
        List<User> list = sqlSession.selectList("test.findUserByUsername", "王五");
        for (User user : list) {
            System.out.println(user);
        }

3.添加用户

    <!-- 添加用户 -->
    <insert id="insert" parameterType="cn.itcast.mybatis.po.User">
        insert into user(username,sex,birthday,address)
            values(#{username},#{sex},#{birthday},#{address})
    </insert>

        //执行SQL
        User user = new User();
        user.setUsername("添加User");
        user.setSex("男");
        user.setBirthday(new Date());
        user.setAddress("未知区域");

        sqlSession.insert("test.insert", user);
        //手动提交事务！！
        sqlSession.commit();

4.添加用户，返回ID

    <!-- 添加用户 返回ID -->
    <insert id="insertRE" parameterType="cn.itcast.mybatis.po.User">
        <selectKey keyProperty="id" resultType="Integer" order="AFTER">
            select LAST_INSERT_ID()
        </selectKey>
        insert into user(username,sex,birthday,address)
            values(#{username},#{sex},#{birthday},#{address})
    </insert>

        //执行SQL
        User user = new User();
        user.setUsername("添加User");
        user.setSex("男");
        user.setBirthday(new Date());
        user.setAddress("未知区域");

        int id = sqlSession.insert("test.insertRE", user);

        //手动提交事务！！
        sqlSession.commit();

        System.out.println(user.getId());

5.更新用户

    <!-- 更新用户 -->
    <update id="update" parameterType="cn.itcast.mybatis.po.User">
        update user set username=#{username},sex=#{sex},birthday=#{birthday},address=#{address} where id = #{id}
    </update>

        //执行SQL
        User user = new User();
        user.setId(31);
        user.setUsername("更新User");
        user.setSex("女");
        user.setBirthday(new Date());
        user.setAddress("火星");

        sqlSession.update("test.update", user);
        //手动提交事务！！
        sqlSession.commit();

6删除用户

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

        //执行SQL
        sqlSession.delete("test.delete", 31);

        //手动提交事务！！
        sqlSession.commit();