JavaWeb学习笔记-mybatis-25-与spring整合

需要spring通过单例方式管理SqlSessionFactory
spring和mybatis整合生成代理对象，使用SqlSessionFactory创建SqlSession（spring和mybatis整合自动完成），持久层的mapper需要由spring进行管理

整合环境搭建

• jar包
  
  • spring包
  • mybatis_spring整合包
  • mybatis包
  • …

SqlSessionFactory配置

applicationContext.xml

在applicationContext.xml配置sqlSessionFactory和数据源

<?xml version="1.0" encoding="utf-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
       http://www.springframework.org/schema/beans/spring-benas-3.2.xsd
        http://www.springframework.org/schema/context
        http://www.springframework.org/schema/context/spring-context-3.2.xsd">
    <!--sqlSessionFactory-->
    <bean id="ssqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <!--加载mybatis配置文件-->
        <property name="configLocation" value="mybatis/SqlMapConfig.xml"/>
        <!--数据源-->
        <property name="dataSource" ref="dataSource"/>
    </bean>

    <!--数据源，使用dbcp-->
    <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>

    <!--加载配置文件-->
    <context:property-placeholder location="classpath:db.properties"/>
</beans>

原始dao开发

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.sws.mapper.User">
          select * from user where id = #{id}
    </select>

</mapper>

在SqlMapConfig.xml中加载user.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>
    <!--别名定义-->
    <typeAliases>
        <package name="com.sws.mapper"/>
    </typeAliases>

    <!--加载映射文件-->
    <mappers>
        <mapper  resource="sqlmap/User.xml"/>
    </mappers>
</configuration>

dao(继承SqlSessionDaoSupport)

UserDao.java

package com.sws.dao;

import com.sws.mapper.User;

public interface UserDao {
    public User findUserById(int id) throws Exception;
}

dao接口实现UserDaoImp.java,通过spring注入sqlSessionFactory

public class UserDaoImpl extends SqlSessionDaoSupport implements UserDao{

    public User findUserById(int id) throws Exception {
        //继承SqlSessionDaoSupport，通过this.getSqlSession()得到sqlsession
        SqlSession sqlSession = this.getSqlSession();
        User user = sqlSession.selectOne("test.findUserById",id);
        return user;
    }
}

配置dao

applicationContext.xml

    <!--原始dao接口-->
    <bean id="userDao" class="com.sws.dao.UserDaoImpl">
        <property name="sqlSessionFactory" ref="sqlSessionFactory"></property>
    </bean>

mapper代理开发

mapper.xml和mapper.java

<?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="com.sws.mapper.UserMapper">

    <select id="findUserById" parameterType="int" resultType="User">
          select * from user where id = #{id}
    </select>

</mapper>

package com.sws.mapper;

import com.sws.entity.User;

public interface UserMapper {
    public User findUserById(int id) throws Exception;

}

通过mapperFactoryBean创建代理对象

applicationContext.xml配置

<!--mapper配置
    MapperFactoryBean根据mapper接口生成代理对象-->
    <bean id="userMapper" class="org.mybatis.spring.mapper.MapperFactoryBean">
        <property name="mapperInterface" value="com.sws.mapper.UserMapper"/>
        <property name="sqlSessionFactory" ref="sqlSessionFactory"></property>

SqlMapConfig.xml

    <!--加载映射文件-->
    <mappers>
        <package name="com.sws.mapper"/>
    </mappers>

问题

需要争对每一个mapper进行配置
解决方法
applicationContext.xml

    <!--mapper批量扫描,从mapper包中扫描mapper接口，自动创建代理对象并且在spring容器中注册
    mapper接口类名和mapper.xml映射文件保持一致，且在同一目录下
    自动扫描出的mapper的bean的id为mapper类名（首字母小写）-->
    <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
        <!--指定扫描包名
        如果扫描多个包，包名使用逗号隔开
        -->
        <property name="basePackage" value="com.sws.mapper"/>
        <property name="sqlSessionFactoryBeanName" value="sqlSessionFactory"/>
    </bean>

SqlMapConfig.xml

    <mappers>
        <!--和spring整合后，使用mapper扫描器，这里可以不需要配置了-->
        <package name="com.sws.mapper"/>
    </mappers>