mybatis与spring的整合（代码实现）
需要jar包：
mybatis核心包；依赖包；log4j包；spring croe;beans;tx;aop;aspects;context;expression;jdbc; mybatis和spring得整合jar包；
环境配置：
1）mybatis.xml和mapper.xml配置在第一节有
2）spring.xml配置在第二节有
当配置好所有得环境，引入jar包后，开始写代码。
1.先配置mybatis.xml文件：
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE configuration PUBLIC "http://mybatis.org/dtd/mybatis-3-config.dtd" "mybatis-3-config.dtd" >
<configuration>
<typeAliases>
<package name="com.bean" />
</typeAliases>
</configuration>
2.现在用spring.xml配置，–>开启自动扫描（注释）–>properties文件得placeholder–>连接数据库
<context:component-scan base-package="com.service" />
<context:property-placeholder location="classpath:db.properties" />
<bean id="datasource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
<property name="driverClass" value="${Adriver}"></property>
<property name="JdbcUrl" value="${Aurl}"></property>
<property name="user" value="${Ausername}"></property>
<property name="password" value="${Apassword}"></property>
<property name="maxPoolSize" value="10"></property>
<property name="initialPoolSize" value="3"></property>
</bean>
3.写一个bean（UsersBean）
package com.bean;public class UsersBean { private int uid;
private String uname;
private String upass; public int getUid() {
return uid;
} public void setUid(int uid) {
this.uid = uid;
} public String getUname() {
return uname;
} public void setUname(String uname) {
this.uname = uname;
} public String getUpass() {
return upass;
} public void setUpass(String upass) {
this.upass = upass;
}}
4.写一个UsersDao,对数据库数据进行操作
package com.dao;import java.util.List;import org.apache.ibatis.annotations.Param;import com.bean.UsersBean;public interface IUsersDao { public List<UsersBean> queryAll();
}
5.写一个mapper.xml映射文件（IUsersDao.xml）
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper PUBLIC "http://mybatis.org/dtd/mybatis-3-mapper.dtd" "mybatis-3-mapper.dtd" >
<mapper namespace="com.dao.IUsersDao">
<select id="queryAll" resultType="usersbean">
select * from users
</select>
</mapper>
6.spring.xml配置，sqlSessionFactory()创建，mapper.xml文件得映射
<bean id="factory" class="org.mybatis.spring.SqlSessionFactoryBean">
<property name="configLocation" value="classpath:mybatis/mybatis-config.xml"></property>
<property name="dataSource" ref="datasource"></property>
</bean>
<bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
<property name="basePackage" value="com.dao"></property>
<property name="sqlSessionFactoryBeanName" value="factory"></property>
</bean>
7.UsersServiceImpl类继承IUsersService ，其中：(@Resource(name=”IUsersDao”))name属性是值service层和dao层得关联
一般如果dao层mapper.xml文件名为UserDao,则name=”userDao”,不写就是默认为userDao.但我这里得name=”IUserDao”.
package com.service.impl;import java.util.List;import javax.annotation.Resource;import org.springframework.stereotype.Service;import com.bean.UsersBean;
import com.dao.IUsersDao;
import com.service.IUsersService;@Service
public class UsersServiceImpl implements IUsersService { @Resource
private IUsersDao usersDao; @Override
public List<UsersBean> findAll() {
// TODO Auto-generated method stub
return usersDao.queryAll();
}
}
在这里遇到了一个问题 ，在spring.xml中我写的是批量配置使用了SqlSessionFactoryBean 本@(Resource name=”userDao”)第一个字母小写，可能是name=”iUserDao”或者name=”IuserDao”,但都是错误得，因为我用的是以I开头的接口名，然后(@Resource(name=”IUsersDao”)是这样的。这是一个问题我不太懂，不懂它底层是怎样实现，希望大家懂得可以留言，我们逐一讨论。
8.测试；（junit）
package test;import java.util.List;import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;import com.bean.UsersBean;
import com.service.impl.UsersService;class Test { @org.junit.jupiter.api.Test
void test() {
// 实例化UsersService对象，调用显示方法
ApplicationContext app = new ClassPathXmlApplicationContext("spring/spring.xml");
UsersService us = app.getBean("UsersService", UsersService.class);
List<UsersBean> list = us.findAll();
for (UsersBean user : list) {
if (list != null) {
System.out.println("uid:" + user.getUid() + "\tuname:" + user.getUname() + "\tupwd:" + user.getUpwd());
}
}
System.out.println(app);
}
}
ok！！
多做笔记，加深记忆！！！
学无止境。
