MyBatis使用
来源：互联网 发布：webbench 源码 编辑：程序博客网 时间：2024/05/17 22:13
简书链接：http://www.jianshu.com/p/9803529e7c1e
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
别人总结很具体：http://www.cnblogs.com/inspurhaitian/p/4647485.html
参考文章http://www.cnblogs.com/inspurhaitian/p/4647485.html
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