MyBatis入门-基本配置和查询

MyBatis入门-基本配置和查询

1、创建基本的Java web工程

2、导入依赖的jar包，这里只有两个不许的Jar「这里使用的是MySql数据库」。

mybatis-3.4.4.jar                            mybatis核心jar包mysql-connector-java-5.0.8-bin.jar           MySql JDBC驱动包

3、在src根目录创建mybatis全局配置文件mybatis-config.xml，文件名可以随意，按照自己的需求，文件内容如下所示：

<?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>    <properties resource="jdbc.properties">    </properties>    <environments default="development">        <environment id="development">            <transactionManager type="JDBC" />            <dataSource type="POOLED">                <property name="driver" value="${driver}" />                <property name="url" value="${url}" />                <property name="username" value="${username}" />                <property name="password" value="${password}" />            </dataSource>        </environment>    </environments>    <mappers>        <mapper resource="com/zhxiong/empty/mapper/UserMapper.xml" />    </mappers></configuration>

4、在src根目录创建jdbc.properties文件，以供mybatis-config.xml文件使用，具体的内容如下所示：

driver=com.mysql.jdbc.Driverurl=jdbc:mysql://localhost:3306/testDBusername=rootpassword=root

5、创建实体类User.java并创建对应的数据库对象，代码如下所示：

package com.zhxiong.empty.bean;public class User {    private Long id;    private String userName;    private String password;    public Long getId() {        return id;    }    public void setId(Long id) {        this.id = id;    }    public String getUserName() {        return userName;    }    public void setUserName(String userName) {        this.userName = userName;    }    public String getPassword() {        return password;    }    public void setPassword(String password) {        this.password = password;    }    @Override    public String toString() {        return "User [id=" + id + ", userName=" + userName + ", password=" + password + "]";    }}

数据库创建代码如下：

DROP TABLE IF EXISTS `sys_user`;CREATE TABLE `sys_user` (  `id` bigint(20) NOT NULL AUTO_INCREMENT,  `password` varchar(255) COLLATE utf8_bin DEFAULT NULL,  `user_name` varchar(255) COLLATE utf8_bin DEFAULT NULL,  PRIMARY KEY (`id`)) ENGINE=InnoDB AUTO_INCREMENT=3 DEFAULT CHARSET=utf8 COLLATE=utf8_bin;

6、定义Mapper接口UserMapper.java，代码如下所示：

package com.zhxiong.empty.mapper;import com.zhxiong.empty.bean.User;public interface UserMapper {    User getUser(Long id);}

7、编写映射文件，UserMapper.xml，代码如下所示：

<?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.zhxiong.empty.mapper.UserMapper">  <select id="getUser" resultType="com.zhxiong.empty.bean.User">    select id,user_name userName,password from sys_user where id = #{id}  </select></mapper>

8、在全局配置中引入映射文件，具体看上面的全局配置文件。

9、编写测试。代码如下：

package com;import java.io.IOException;import java.io.InputStream;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 com.zhxiong.empty.bean.User;import com.zhxiong.empty.mapper.UserMapper;public class AppTest {    @Test    public void myBatisTest() throws IOException {        String resource = "mybatis-config.xml";        InputStream inputStream = Resources.getResourceAsStream(resource);        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);        SqlSession session = sqlSessionFactory.openSession();        UserMapper mapper = session.getMapper(UserMapper.class);        User user = session.selectOne("com.zhxiong.empty.mapper.UserMapper.getUser", 1);        User user2 = mapper.getUser(1L);        System.out.println(user);        System.out.println(user2);        session.commit();        session.close();    }}

至此，我们完成了MyBatis基本入门示例。