Spring 整合Mybatis dao原始方法

Posted 2020-12-02 Advancing Swift

先看一下项目图,基本就理解了整合的内容

这次主角不再是Mybats的配置文件SqlMapConfig.xml了,而是Spring的applicationContext.xml

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-4.1.xsd
    http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.1.xsd
    http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.1.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.1.xsd
    http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-4.1.xsd">

    <context:property-placeholder location="classpath:db.properties" />
    
    <!-- 数据源 -->
    <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}" />
    </bean>
    
    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <property name="dataSource" ref="dataSource"></property>
        <property name="configLocation" value="classpath:SqlMapConfig.xml"></property>
        <property name="typeAliasesPackage" value="com.itheima.mybatis.pojo"></property>
    </bean>
    
    <bean id="userDao" class="com.itheima.mybatis.dao.UserDaoImpl">
        <property name="sqlSessionFactory" ref="sqlSessionFactory"></property>
    </bean>
    
    <bean id="transactionManager"    
        class="org.springframework.jdbc.datasource.DataSourceTransactionManager">    
        <property name="dataSource" ref="dataSource" />    
    </bean>  
    <tx:annotation-driven transaction-manager="transactionManager"/>
</beans>

Spring同样开始整合数据源datasource

IoC控制反转生成sqlSessionFactory对象,注意有一个属性configLocation,用来关联Mybatis的映射文件SqlMapConfig.xml,

也是在该对象中对包进行别名操作

IoC控制反转生成要调用的对象userDao,其实现类继承SqlSessionDaoSupport,还要注入属性sqlSessionFactory

Mybatis配置文件SqlMapConfig.xml代码:

<?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">
<!-- 配置 -->
<configuration>
    <!-- 加载sql映射文件 -->
    <mappers>
        <mapper resource="sqlmap/UserMapper.xml" />
    </mappers>
</configuration>

映射文件UserMapper.xml

<!DOCTYPE mapper
PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<!-- 映射，存放sql语句 -->
<!-- 
namespace：分类管理sql语句
唯一确定sql语句：namespace + "." + id
 -->
<mapper namespace="test">
    <!-- 
        查询使用select标签
        id：sql语句标识符，通常也称为statement的id
        parameterType：参数类型（输入映射）
        resultType：结果类型（输出映射），配置为pojo，那么mybatis就把结果集中的每一条记录封装为指定的pojo
     -->
    <select id="queryUserById" parameterType="Integer" resultType="user">
        <!-- 
            #{}固定取参语法
            #{}取参名称：parameterType为基础数据类型的时候，名称任意，建议见名思意
                        传 入pojo的时候，取参名称为属性名
            #{}原理：预编译语句，可以防止sql注入
            #{}对字符串参数会自动添加单引号对
         -->
        select * from user where uid=#{uid}
    </select>
</mapper>

接口

package com.itheima.mybatis.dao;

import com.itheima.mybatis.pojo.User;

public interface UserDao {
    User queryUserById(int id);
}

实体类

package com.itheima.mybatis.dao;

import org.mybatis.spring.support.SqlSessionDaoSupport;

import com.itheima.mybatis.pojo.User;

public class UserDaoImpl extends SqlSessionDaoSupport implements UserDao {

    public User queryUserById(int id) {
        // TODO Auto-generated method stub
        // 不需要关闭session，因为父类当中完成拦截关闭动作
        User user = super.getSqlSession().selectOne("test.queryUserById", id);
        return user;
    }

}

 测试类

package com.itheima.mybatis.test;

import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.springframework.transaction.annotation.Transactional;

import com.itheima.mybatis.dao.UserDao;
import com.itheima.mybatis.pojo.User;

public class TestUserDao {
    private ApplicationContext ctx;
    
    @Test
    @Transactional
    public void testQueryUserById() {
        ctx = new ClassPathXmlApplicationContext("applicationContext.xml");
        UserDao userDao = ctx.getBean(UserDao.class);
        User user = userDao.queryUserById(3);
        System.out.println(user);
    }
}