初识MyBatis

MyBatis框架介绍

MyBatis是一个开源的数据持久层框架。它内部封装了通过JDBC访问数据库的操作，支持普通的SQL查询，存储过程和高级映射，几乎消除了所有的JDBC代码和参数的手工设置以及结果集的检索，MyBatis作为持久层框架，其主要思想是将程序中的大量的SQL语句剥离出来，配置在配置文件中，实现SQL的灵活配置。这样做的好处是将SQL与程序代码分离，可以在不修改程序代码的情况下，直接在配置文件中修改

MyBatis的前身是iBatis，本是Apache的一个开源项目，2010年这个项目由Apache Software Foundation迁移到了Google Code，并改名为MyBatis。2013年迁移到Github

MyBatis官网：http://mybatis.org

Github:http://github.com/mybatis

什么是ORM

ORM(Object/Relational Mapping)即对象/关系映射，是一种数据持久化技术。它在对象模型和关系型数据库之间建立起对应关系，并且提供了一种机制，通过javaBean对象去操作数据库表中的数据

初识MyBatis MyBatis是ORM解决方案

基于ORM，MyBatis在对象模型和关系数据库的表之间建立了一座桥梁，通过MyBatis建立SQL关系映射，以便捷地实现数据存储，查询，更改，和删除等操作

下面是入门代码

初识MyBatis

下面是jar包

初识MyBatis

主配置文件

<?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://localhost:3306/test?characterEncoding=utf-8"/>
<property name="username" value="root"/>
<property name="password" value="123456"/>
</dataSource>
</environment>
</environments>
<mappers>
<mapper resource="sqlmap/UserMapper.xml"/>
</mappers>

</configuration>

mapper.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="test">

   

   <select id="findUserByID" parameterType="int" resultType="com.bdqn.cn.user.User">
       select * from User where id=#{id}
   </select>

   
   <select id="findUserByName" parameterType="java.lang.String" resultType="com.bdqn.cn.user.User">

       
       select * from user where username like '%${value}%';

   </select>

   <insert id="insertUser" parameterType="com.bdqn.cn.user.User" >

       

       <selectKey keyProperty="id" order="AFTER" resultType="java.lang.Integer">

           SELECT LAST_INSERT_ID()

       </selectKey>

       insert into User(username,sex,birthday,address) values(#{username},#{sex},#{birthday},#{address})

   </insert>


   <delete id="deleteUser" parameterType="java.lang.Integer">

       delete from user where id=#{id}

   </delete>

   <update id="updateUser" parameterType="com.bdqn.cn.user.User">

       update user set username=#{username},sex=#{sex},birthday=#{birthday},address=#{address} where id=#{id}

   </update>


</mapper>

实体类

public class User {

   private int id;
   private String username;
   private String sex;
   private Date birthday;
   private String address;
   public User() {
       super();
       // TODO Auto-generated constructor stub
   }
   public User(int id, String username, String sex, Date birthday,
           String address) {
       super();
       this.id = id;
       this.username = username;
       this.sex = sex;
       this.birthday = birthday;
       this.address = address;
   }
   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 + "]";
   }






}
测试类：

public class MybatisFirst {

   //根据用户查询最后得到一条记录
   @Test
   public void findUserByIDTest(){

       try {
           //sqlmap配置文件
           String resource = "SqlMapConfig.xml";