mybatis基础学习一

1. Mybatis介绍(ibatis)

MyBatis是支持普通****SQL****查询，存储过程和高级映射的优秀持久层框架。MyBatis消除了几乎所有的JDBC代码和参数的手工设置以及对结果集的检索封装。MyBatis可以使用简单的XML或注解用于配置和原始映射，将接口和Java的POJO（Plain Old Java Objects，普通的Java对象）映射成数据库中的记录.

2. mybatis快速入门

编写第一个基于mybaits的测试例子:

2.1添加jar包

【mybatis】
mybatis-3.1.1.jar

【MYSQL驱动包】
mysql-connector-java-5.1.7-bin.jar

2.2建库+表

create database mybatis;

use mybatis;

CREATE TABLE users(id INT PRIMARY KEY AUTO_INCREMENT, NAME VARCHAR(20), age INT);

INSERT INTO users(NAME, age) VALUES(‘Tom’, 12);

INSERT INTO users(NAME, age) VALUES(‘Jack’, 11);

2.3 添加mybatis配置文件conf.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>
    <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://172.171.2.161:3306/mybatis" />
                <property name="username" value="root" />
                <property name="password" value="root123" />
            </dataSource>
        </environment>
    </environments>
<!--后面2.6章节添加-->
    <mappers>
        <mapper resource="mybatis/userMapper.xml"/>
    </mappers>
</configuration>

2.4 定义表所对应的实体类

package mybatis;
public class User
{
    private int id;
    private String name;
    private int age;
    public User(final int id, final String name, final int age)
    {
        super();
        this.id = id;
        this.name = name;
        this.age = age;
    }
    public User()
    {
        super();
    }
    public int getId()
    {
        return id;
    }
    public void setId(final int id)
    {
        this.id = id;
    }
    public String getName()
    {
        return name;
    }
    public void setName(final String name)
    {
        this.name = name;
    }
    public int getAge()
    {
        return age;
    }
    public void setAge(final int age)
    {
        this.age = age;
    }
    @Override
    public String toString()
    {
        return "User [id=" + id + ", name=" + name + ", age=" + age + "]";
    }
}

2.5 定义操作users表的sql映射文件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="mybatis.userMapper"> 
    <select id="getUser" parameterType="int" 
        resultType="mybatis.User">
        select * from users where id=#{id}
    </select>
</mapper>

2.6 在conf.xml文件中注册userMapper.xml文件

<mappers>
    <mapper resource="mybatis/userMapper.xml"/>
</mappers>

2.7 编写测试代码：执行定义的select语句

package mybatis;
import java.io.IOException;
import java.io.InputStream;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
public class Test
{
    public static void main(final String[] args) throws IOException
    {
        String resource = "conf.xml";
        InputStream is = Test.class.getClassLoader().getResourceAsStream(resource);
        SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(is);
        SqlSession session = factory.openSession();
        String statement = "mybatis.userMapper.getUser";
        User user = session.selectOne(statement, 1);
        System.out.println(user);
    }
}

来自为知笔记(Wiz)