1.简单入门mybatis框架

1.核心包

mysql-connector-java-5.1.21-bin.jar

mybatis-3.1.1.jar

2.其它jar

asm-3.3.1.jar

cglib-2.2.2.jar

commons-logging-1.1.1.jar

log4j-1.2.16.jar

slf4j-api-1.6.2.jar

slf4j-log4j12-1.6.2.jar

在mybatis开发中可获取

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在项目中的结构是

3.mybatis.xml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>
    <environments default="development">
        <environment id="development">
            <transactionManager type="JDBC" />
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.jdbc.Driver" />
                <property name="url" value="jdbc:mysql://127.0.0.1:3306/mybatis" />
                <property name="username" value="root" />
                <property name="password" value="root" />
            </dataSource>
        </environment>
    </environments>
    <mappers>
        <!-- 这个是数据库操作的xml文件 -->
        <mapper resource="UserMapper.xml" />
    </mappers>
</configuration>

４.配置UserMapper.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">
  
<mapper namespace="com.gzcgxt.erp.UserMapper">
    <select id="select" resultType="com.gzcgxt.erp.hello.User">
        select * from user where id = #{id}
    </select>
</mapper>

5.创建一个User对象

package com.gzcgxt.erp.hello;

import lombok.Data;

@Data
public class User {
    private Integer id;
    private String    name;
}

6.测试代码

package com.gzcgxt.erp.hello;

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;

public class App {
    
    //方式一
    @Test
    public void sayHello()
    {
        // 获取当前程序的类加载器
        ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
        
        // 将mybatis配置文件和UserMaper文件读取进内存中
        InputStream in = classLoader.getResourceAsStream("mybatis.xml");
        
        // 构造mybatis工厂对像
        SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(in);
        
        // 获取连接
        SqlSession session = factory.openSession();
        
        // 查询单个User对象
        User user = session.selectOne("com.gzcgxt.erp.UserMapper.select", 2);
        
        System.out.println(user);
        
    }
    
    //方式二
    @Test
    public void sayHello2() throws Exception
    {
        
        InputStream in = Resources.getResourceAsStream("mybatis.xml");
        
        // 构造mybatis工厂对像
        SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(in);
        
        // 获取连接
        SqlSession session = factory.openSession();
        
        // 查询单个User对象
        User user = session.selectOne("com.gzcgxt.erp.UserMapper.select", 2);
        
        System.out.println(user);
        
    }

}