Mybatis+Spring基于接口编程的例子

maven创建web项目，架构如下图

maven引用如下图，其中jdbc-driver由于版权问题在maven仓库找不到，是我自己本地注册的。

spring配置文件applicationContext.xml如下

<?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"
	xmlns:aop="http://www.springframework.org/schema/aop"
	xmlns:tx="http://www.springframework.org/schema/tx"
	xsi:schemaLocation="http://www.springframework.org/schema/beans 
	http://www.springframework.org/schema/beans/spring-beans-3.0.xsd 
	http://www.springframework.org/schema/context 
	http://www.springframework.org/schema/context/spring-context-3.0.xsd 
	http://www.springframework.org/schema/aop 
	http://www.springframework.org/schema/aop/spring-aop-3.0.xsd 
	http://www.springframework.org/schema/tx 
	http://www.springframework.org/schema/tx/spring-tx-3.0.xsd">
	
	<description>Spring公共配置文件 </description>
	
	<context:component-scan base-package="org.wusq.project" />
	<context:annotation-config/>
	<context:property-placeholder location="classpath:application.properties" />
	
	<bean id="dataSource" class="com.jolbox.bonecp.BoneCPDataSource"
		destroy-method="close" lazy-init="false">
		<property name="driverClass" value="${jdbc.driver}" />
		<property name="jdbcUrl" value="${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 name="configLocation">
	   	  <value>classpath:mybatis-config.xml</value>
	   </property>
	</bean>

	<bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
		<property name="dataSource" ref="dataSource" />
	</bean>
	
	<tx:annotation-driven transaction-manager="transactionManager"/>
	
	<!-- scan for mappers and let them be autowired -->
	<bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
		<property name="basePackage" value="org.wusq.project" />
		<property name="annotationClass" value="org.wusq.project.dao.Mapper"></property>
	</bean>
	
</beans>

dao包中的两个接口如下

package org.wusq.project.dao;

import java.io.Serializable;

public interface Dao<T> {
	
	int delete(Serializable id);
	
	int insert(T o);
	
	int update(T o);

}

package org.wusq.project.dao;

public @interface Mapper {
	
}

user包中，User实体类，两个属性id和name，省略代码。其他代码如下

package org.wusq.project.user;

import org.wusq.project.dao.Dao;
import org.wusq.project.dao.Mapper;

@Mapper
public interface UserMapper extends Dao<User>{
	
	User selectByName(String name);

}

<?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="org.wusq.project.user.UserMapper">
	
	<insert id="insert" parameterType="User">
		<![CDATA[
 		insert into users (id,name)
 		values 
 		(#{id,jdbcType=VARCHAR},#{name,jdbcType=VARCHAR})
 		]]>
	</insert>
	
	<select id="selectByName" parameterType="String" resultType="User">
		select id,name from users where name=#{name}
	</select>
	
</mapper>

package org.wusq.project.user;

public interface UserService {
	
	void save(User o);
	
	User queryByName(String id);

}

package org.wusq.project.user;

import javax.annotation.Resource;

import org.springframework.stereotype.Service;

@Service
public class UserServiceImpl implements UserService{
	
	@Resource
	private UserMapper userMapper;

	@Override
	public void save(User o) {
		userMapper.insert(o);
	}

	@Override
	public User queryByName(String name) {
		return userMapper.selectByName(name);
	}

}

mybatis-config.xml配置如下

<?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>
	<settings>
		<!-- changes from the defaults for testing -->
		<setting name="cacheEnabled" value="false" />
		<setting name="useGeneratedKeys" value="true" />
		<setting name="defaultExecutorType" value="REUSE" />
	</settings>
	
	<typeAliases>
		<typeAlias type="org.wusq.project.user.User" alias="User"/>
	</typeAliases>
	
</configuration>

测试类如下

package test;

import org.junit.BeforeClass;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.wusq.project.user.User;
import org.wusq.project.user.UserService;

public class ServiceTest {
	
private static ApplicationContext act = null;
	
	@BeforeClass
	public static void setUpBeforeClass() throws Exception {
		act = new ClassPathXmlApplicationContext("applicationContext.xml");
	}
	
	@Test
	public void test() throws Exception{
		UserService service=(UserService)act.getBean("userServiceImpl");
		
		User o = new User();
		o.setId("1");
		o.setName("wusq");
		
		service.save(o);
		
//		User u = service.queryByName("wusq");
//		System.out.println(u.getName());
	}

}

Mybatis+Spring基于接口编程，核心dao只有一个接口，即该例中的Dao，里面可以写一些通用接口。然后面向对象编程中，可以在实体Mapper中扩展自用接口。service中调用dao层接口时，由mybatis代理实现。

参考资料：MyBatis+Spring基于接口编程的原理分析