Spring整合MyBatis (使用扫描包配置mapper代理)
pojo是根据表生成的实体类,属性名要跟字段名相同,不相同sql语句查询时用别名。
首先导jar包
实体类
public class User {
private Integer id;
private String username;// 用户姓名 private String sex;// 性别 private Date birthday;// 生日 private String address;// 地址 }
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第一步:
编写MyBatis配置文件SqlMapConfig.xml(虽然里面可以什么也不写除了头,但是必须有)。
<?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>
</configuration>
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第二步:
编写Spring 配置文件applicationContext.xml
(
db.properties:文件里面放的是连接数据库的相关信息。
jdbc.driver=com.mysql.jdbc.Driver jdbc.url=jdbc:mysql://localhost:3306/t003?characterEncoding=utf-8 jdbc.username=test01 jdbc.password= )
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<?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"> <!-- 加载配置文件 --> <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> <!-- sqlSessonFactory的配置 --> <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean"> <!-- 配置数据库连接池 --> <property name="dataSource" ref="dataSource"></property> <!-- 加载配置文件 --> <property name="configLocation" value="classpath:SqlMapConfig.xml"></property> </bean> <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer" > <property name="basePackage" value="cn.test" /> </bean> </beans>
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第四步编写接口相对应的xml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">
<!-- namespace是命名空间,作用sql语句的隔离,后面还有重要作用 #{}作用就是占位符,相当于jdbc的“?” parameterType:查询的参数类型
resultType:查询结果的数据类型,如果给pojo应该给全路径。 -->
<!-- mapper代理的开发规则: 1、namespace必须时候接口的全限定名 2、Statementid必须和接口的方法名称一致 3、接口方法的参数类型要和parameterType要一致
4、接口方法的返回值类型要和resultType一致 -->
<mapper namespace="cn.test.mybatis.po.UserMapper"> <!-- 别名不区分大小写 --> <select id="getUserById" parameterType="int" resultType="cn.test.mybatis.po.User"> SELECT * FROM `user` WHERE id=#{id}; </select> <!-- 如果查询结果返回list, resultType设置为list中一个元素的数据类型 ${}字符串拼接指令 --> <select id="getUserByName" parameterType="string" resultType="cn.test.mybatis.po.User"> SELECT * FROM `user` WHERE username LIKE '%${value}%' </select> <!-- 美丽的分界线 只测试最简单的上边两个方法 --> <!-- 参数为pojo时,#{}中的名称就是pojo的属性 --> <!-- <insert id="insertUser" parameterType="cn.test.mybatis.po.User"> keyProperty:对于pojo的主键属性 resultType:对应主键的数据类型 order:是在insert语句执行之前或者之后。 如果使用uuid做主键,应该先生成主键然后插入数据,此时应该使用Before <selectKey keyProperty="id" resultType="int" order="AFTER"> SELECT LAST_INSERT_ID() </selectKey> INSERT into user (username,birthday,sex,address) values (#{username}, #{birthday}, #{sex}, #{address}) </insert> --> <!-- <select id="getUserByQueryVo" parameterType="queryvo" resultType="user"> SELECT * FROM `user` WHERE id=#{user.id}; </select> --> <!-- 查询用户表中的记录数 --> <!-- <select id="getUserCount" resultType="int"> SELECT count(*) FROM `user` </select> <sql id="find_user_list_where"> <where> <if test="id!=null"> and id=#{id} </if> <if test="username != null and username != ''"> and username like '%${username}%' </if> </where> </sql> <sql id="user_field_list"> id,username,birthday,sex,address </sql> --> <!-- <select id="findUserList" parameterType="user" resultType="user"> select <include refid="user_field_list" /> from user <include refid="find_user_list_where" /> </select> --> <!-- 动态sql foreach测试 --> <!-- <select id="findUserByIds" parameterType="queryvo" resultType="user"> SELECT <include refid="user_field_list" /> FROM `user` <where> and id in(1,10,20,21,31) <foreach collection="ids" item="id" open="and id in(" close=")" separator=","> #{id} </foreach> </where> </select> --> </mapper>
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最后测试
public class MyBatisTest {
private ApplicationContext applicationContext; @Before public void init() throws Exception { // 初始化spring容器 applicationContext = new ClassPathXmlApplicationContext("classpath:applicationContext.xml"); } @Test public void testFindUserById() { UserMapper userMapper = applicationContext.getBean(UserMapper.class); List<User> user = userMapper.getUserByName("王五"); for (User user2 : user) { System.out.println(user2.getUsername()); } } @Test public void test() { UserMapper userMapper = applicationContext.getBean(UserMapper.class); User userById = userMapper.getUserById(1); System.out.println(userById); } }