原文链接：http://blog.csdn.net/qq_22329521/article/details/75051031
导包
- 下载mybaits https://github.com/mybatis/mybatis-3/releases
- 下载连接mysql驱动
配置sqlMapconfig.xml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/mybatis?characterEncoding=utf-8" />
<property name="username" value="root" />
<property name="password" value="" />
</dataSource>
</environment>
</environments>
<!--Mapper的位置,相当于每个对象的sql的映射文件-->
<mappers>
<mapper resource="sqlmap/User.xml"></mapper>
</mappers>
</configuration>
User.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">
<!--写sql语句-->
<!--namespace命名空间，避免不同的mapper文件底下有同样的id的sql方法-->
<mapper namespace="test">
<!--通过id查询一个用户-->
<select id="findUserById" parameterType="Integer" resultType="com.fmt.mybatis.pojo.User">
select * from user where id=#{v};
</select>
<!--
#{} 表示占位符()
${value} 表示字符串拼接
-->
<!--<select id="findUserByName" parameterType="String" resultType="com.fmt.mybatis.pojo.User">-->
<!--select * from user where username like '%${value}%';-->
<!--</select>-->
<!--防止sql注入-->
<select id="findUserByName" parameterType="String" resultType="com.fmt.mybatis.pojo.User">
select * from user where username like "%"#{v}"%";
</select>
<insert id="addUser" parameterType="com.fmt.mybatis.pojo.User">
<!-- 添加用户返回调用获取最后插入的id返回给用户id-->
<selectKey keyProperty="id" resultType="Integer" order="AFTER">
select LAST_INSERT_ID()
</selectKey>
insert into user (username,birthday,address,sex) VALUE (#{username},#{birthday},#{address},#{sex})
</insert>
<update id="updateUserById" parameterType="com.fmt.mybatis.pojo.User">
update user set username=#{username},sex=#{sex},birthday=#{birthday},address=#{address}
where id=#{id}
</update>
<delete id="deleteUserById" parameterType="Integer">
DELETE from user where id=#{id}
</delete>
</mapper>
增删改查
@Test
public void fun1() throws IOException {
// 加载核心配置文件
String resource="sqlMapConfig.xml";
InputStream resourceAsStream = Resources.getResourceAsStream(resource);
//创建sqlSessionFactory
SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(resourceAsStream);
//创建sqlsession
SqlSession sqlSession = factory.openSession();
/**
User o = sqlSession.selectOne("test.findUserById", 10);
System.out.println(o);
List<User> users=sqlSession.selectList("test.findUserByName","五");
for (User u:users){
System.out.println(u);
}
*/
/**
User user = new User();
user.setAddress("北京");
user.setSex("男");
user.setBirthday(new Date());
user.setUsername("富媒体");
int i= sqlSession.insert("test.addUser",user);
sqlSession.commit();
Integer id = user.getId();
System.out.println(id);
*/
/**
User user = new User();
user.setAddress("上海");
user.setSex("男");
user.setBirthday(new Date());
user.setUsername("富媒体");
user.setId(28);
int i= sqlSession.update("test.updateUserById",user);
sqlSession.commit();
*/
/*
int i= sqlSession.delete("test.deleteUserById",28);
sqlSession.commit();
*/
}
封装dao调用getMapper方法
public interface UserMapper {
//遵循4个原则
//接口名字==User.xml中的id
//返回类型与Mapper.xml中的返回类型一直
//方法的入参与Mapper.xml的入参一致
//命名空间绑定接口
List<User> findUserByQueryVo(QueryVo vo);
public Integer countUser();
}
<mapper namespace="com.fmt.mybatis.UserMapper">
<select id="findUserByQueryVo" parameterType="com.fmt.mybatis.pojo.QueryVo" resultType="com.fmt.mybatis.pojo.User">
select * from user where username like "%"#{user.username}"%";
</select>
<select id="countUser" resultType="Integer">
SELECT count(*) from USER
</select>
</mapper>
@Test
public void fun5() throws IOException {
// 加载核心配置文件
String resource="sqlMapConfig.xml";
InputStream resourceAsStream = Resources.getResourceAsStream(resource);
//创建sqlSessionFactory
SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(resourceAsStream);
//创建sqlsession
SqlSession sqlSession = factory.openSession();
UserMapper mapper = sqlSession.getMapper(UserMapper.class);
QueryVo queryVo = new QueryVo();
User user = new User();
user.setUsername("五");
queryVo.setUser(user);
List<User> userByQueryVo = mapper.findUserByQueryVo(queryVo);
for (User u:userByQueryVo){
System.out.println(u);
}
System.out.println(mapper.countUser());
}
如果数据库字段与对象中的字段不一致使用resultmap来处理
<resultMap id="orders" type="com.fmt.mybatis.pojo.Orders">
<!--数据库字段与java对象中不同的字段映射-->
<result column="user_id" property="userId"/>
</resultMap>
<!--这里是resultMap 之前是resultType-->
<select id="selectOrderList" resultMap="orders">
SELECT id,user_id,number,createtime,note FROM orders
</select>
动态sql
- if/where
<!--where 标签 可以去掉第一个前And-->
<select id="selectUserBySexAndUserName" parameterType="com.fmt.mybatis.pojo.User" resultType="com.fmt.mybatis.pojo.User">
select * from user
<where>
<if test="sex!=null and sex!=''">
sex=#{sex}
</if>
<if test="username!=null and username!=''">
and username =#{username}
</if>
</where>
</select>
别把and放后面 比如 username=#{username} and
User user = new User();
// user.setSex("1");
user.setUsername("张小明");
List<User> users = mapper.selectUserBySexAndUserName(user);
for (User or:users){
System.out.println(or);
}
- sql片段:提取公共是sql语句
<sql id="selector">
SELECT * FROM user
</sql>
<select id="selectuser" parameterType="com.fmt.mybatis.pojo.User" resultType="com.fmt.mybatis.pojo.User">
<include refid="selector"/>
<where>
<if test="sex!=null and sex!=''">
sex=#{sex}
</if>
<if test="username!=null and username!=''">
and username =#{username}
</if>
</where>
</select>
- foreach
<!--多个Id(1,2,3)-->
<!--<select id="selectUserByIds" parameterType="com.fmt.mybatis.pojo.QueryVo" resultType="com.fmt.mybatis.pojo.User">-->
<!--<include refid="selector"></include>-->
<!--<where>-->
<!--id IN -->
<!--<foreach collection="list_ids" item="id" separator="," open="(" close=")">-->
<!--#{id}-->
<!--</foreach>-->
<!--</where>-->
<!--</select>-->
<!--此处的array是传入integer[]数组-->
<select id="selectUserByIds" parameterType="com.fmt.mybatis.pojo.QueryVo" resultType="com.fmt.mybatis.pojo.User">
<include refid="selector"></include>
<where>
id IN
<foreach collection="array" item="id" separator="," open="(" close=")">
#{id}
</foreach>
</where>
</select>
QueryVo queryVo = new QueryVo();
ArrayList<Integer> integers = new ArrayList<>();
integers.add(24);
integers.add(22);
queryVo.setList_ids(integers);
List<User> users = mapper.selectUserByIds(queryVo);
Integer[] integers=new Integer[2];
integers[0]=24;
integers[1]=22;
List<User> users = mapper.selectUserByIds(integers);
for (User or:users){
System.out.println(or);
}
一对一关联
<!--一对一关联-->
<resultMap type="com.fmt.mybatis.pojo.Orders" id="order">
<result column="id" property="id"/>
<result column="user_id" property="userId"/>
<result column="number" property="number"/>
<!-- 一对一 Order对象内部有个user成员变量-->
<association property="user" javaType="com.fmt.mybatis.pojo.User">
<id column="user_id" property="id"/>
<result column="username" property="username"/>
</association>
</resultMap>
<select id="selectOrders" resultMap="order">
SELECT
o.id,
o.user_id,
o.number,
o.createtime,
u.username
FROM orders o
left join user u
on o.user_id = u.id
</select>
List<Orders> selectOrdersList = mapper.selectOrders();
for (Orders orders : selectOrdersList) {
System.out.println(orders);
}
一对多
<!--一对多-->
<resultMap type="com.fmt.mybatis.pojo.User" id="user">
<id column="user_id" property="id"/>
<result column="username" property="username"/>
<!-- 一对多用户里面有订单集合对象 -->
<collection property="ordersList" ofType="com.fmt.mybatis.pojo.Orders">
<id column="id" property="id"/>
<result column="number" property="number"/>
</collection>
</resultMap>
<select id="selectUserList" resultMap="user">
SELECT
o.id,
o.user_id,
o.number,
o.createtime,
u.username
FROM user u
left join orders o
on o.user_id = u.id
</select>
spring与mybatis结合
sqlMapConfig.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>
<!-- 设置别名 -->
<typeAliases>
<!-- 2. 指定扫描包，会把包内所有的类都设置别名，别名的名称就是类名，大小写不敏感 -->
<package name="com.fmt.springmybatis" />
</typeAliases>
<mappers>
<package name="com.fmt.springmybatis"/>
</mappers>
</configuration>
applicationContext.xml
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:context="http://www.springframework.org/schema/context" xmlns:p="http://www.springframework.org/schema/p"
xmlns:aop="http://www.springframework.org/schema/aop" xmlns:tx="http://www.springframework.org/schema/tx"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.0.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.0.xsd
http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.0.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.0.xsd
http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-4.0.xsd">
<context:property-placeholder location="classpath:db.properties"/>
<!-- 数据库连接池 -->
<bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource"
destroy-method="close">
<property name="driverClassName" value="${jdbc.driver}" />
<property name="url" value="${jdbc.url}" />
<property name="username" value="${jdbc.username}" />
<property name="password" value="${jdbc.password}" />
<property name="maxActive" value="10" />
<property name="maxIdle" value="5" />
</bean>
<!-- Mybatis的工厂 -->
<bean id="sqlSessionFactoryBean" class="org.mybatis.spring.SqlSessionFactoryBean">
<property name="dataSource" ref="dataSource"/>
<!-- 核心配置文件的位置 -->
<property name="configLocation" value="classpath:sqlMapConfig.xml"/>
</bean>
<!--原始dao-->
<!--<bean id="userDao" class="com.fmt.springmybatis.dao.UserDaoImp">-->
<!--<property name="sqlSessionFactory" ref="sqlSessionFactoryBean"></property>-->
<!--</bean>-->
<!--Mapper动态代理开发-->
<!--<bean id="userMapper" class="org.mybatis.spring.mapper.MapperFactoryBean">-->
<!--<property name="sqlSessionFactory" ref="sqlSessionFactoryBean"></property>-->
<!--<property name="mapperInterface" value="com.fmt.springmybatis.map.UserMap"></property>-->
<!--</bean>-->
<!--Mapper扫描基本包 扫描-->
<bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
<!--基本包-->
<property name="basePackage" value="com.fmt.springmybatis.map"></property>
</bean>
</beans>
public class test {
@Test
public void test(){
ApplicationContext ac = new ClassPathXmlApplicationContext("applicationContext.xml");
//这是mapper动态代理
// UserMap userMapper = (UserMap) ac.getBean("userMapper");
//这是Mapper扫描基本包
UserMap userMap=ac.getBean(UserMap.class);
User userById = userMap.findUserById(10);
System.out.print(userById);
}
}
mybatis 逆向工程（mybaits需要程序员自己编写sql语句,mybatis官方提供逆向工程,可以针对单表自动生成mybatis执行所需要的代码）
http://blog.csdn.net/h3243212/article/details/50778937
mybatis与hibernate的不同
Mybatis不完全是ORM框架， 因为Mybatis需要程序员自己写sql预计，程序员直接编写原生态sql，可严格控制sql执行性能，灵活度高，但是mybatis无法做到数据库无关性（如果换数据库sql需要重写），hibernate数据无关性强
