mybatis 详解（十一）—— mybatis和spring整合编程语言

#db.properties 
dataSource=org.apache.commons.dbcp.BasicDataSource 
jdbc.driver=com.mysql.jdbc.Driver 
jdbc.url=jdbc:mysql://localhost:3306/mybatisrelation 
jdbc.username=root 
jdbc.password=root 

<?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> 
<!--开启二级缓存  --> 
<settings> 
	<setting name="cacheEnabled" value="true"/> 
</settings> 
 
<!-- 包的别名定义 --> 
<typeAliases> 
	<package name="com.ys.po"/> 
</typeAliases> 
 
<!-- 注意：下面的以前有mybatis全局配置文件管理mapper，现在转移到spring容器管理 --> 
<!-- <mappers> 
    <mapper class="com.ys.po.UserMapper"/> 
 </mappers> --> 
   
</configuration> 

<?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-4.2.xsd 
        http://www.springframework.org/schema/context 
        http://www.springframework.org/schema/context/spring-context.xsd 
        http://www.springframework.org/schema/aop 
        http://www.springframework.org/schema/aop/spring-aop-4.2.xsd 
        http://www.springframework.org/schema/tx 
        http://www.springframework.org/schema/tx/spring-tx.xsd"> 
 
    <!-- 加载classpath下的db.properties文件，里面配了数据库连接的一些信息 --> 
    <context:property-placeholder location="classpath:db.properties"/> 
 
    <!-- 配置数据源 --> 
    <bean id="dataSource" class="${dataSource}" destroy-method="close"> 
        <property name="driverClassName" value="${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> 
 
    <!-- 配置sqlSessionFactory，SqlSessionFactoryBean是用来产生sqlSessionFactory的 --> 
    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean"> 
        <!-- 加载mybatis的全局配置文件，放在classpath下的mybatis文件夹中 --> 
        <property name="configLocation" value="mybatis/mybatis-configuration.xml" /> 
        <!-- 加载数据源，使用上面配置好的数据源 --> 
        <property name="dataSource" ref="dataSource" /> 
    </bean> 
 
</beans> 

package com.ys.po; 
 
public class User { 
	private int id; 
	private String username; 
	private String sex; 
	public int getId() { 
		return id; 
	} 
	public void setId(int id) { 
		this.id = id; 
	} 
	public String getUsername() { 
		return username; 
	} 
	public void setUsername(String username) { 
		this.username = username; 
	} 
	public String getSex() { 
		return sex; 
	} 
	public void setSex(String sex) { 
		this.sex = sex; 
	} 
	@Override 
	public String toString() { 
		return "User [id=" + id + ", username=" + username + ", sex=" + sex 
				+ "]"; 
	} 
} 

1、UserMapper 接口必须要和 UserMapper.xml 文件同名且在同一个包下，也就是说 UserMapper.xml 文件中的namespace是UserMapper接口的全类名 
2、UserMapper接口中的方法名和 UserMapper.xml 文件中定义的 id 一致 
3、UserMapper接口输入参数类型要和 UserMapper.xml 中定义的 parameterType 一致 
4、UserMapper接口返回数据类型要和 UserMapper.xml 中定义的 resultType 一致 

package com.ys.mapper; 
 
import com.ys.po.User; 
 
public interface UserMapper { 
	//根据 id 查询 user 表数据 
	public User selectUserById(int id) throws Exception; 
} 

<?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.ys.mapper.UserMapper"> 
	 
 	<!-- 根据 id 查询 user 表中的数据 
  	   id:唯一标识符，此文件中的id值不能重复 
  	   resultType:返回值类型，一条数据库记录也就对应实体类的一个对象 
  	   parameterType:参数类型，也就是查询条件的类型 
	--> 
	<select id="selectUserById"  
  			resultType="com.ys.po.User" parameterType="int"> 
    	select * from user where id = #{id} 
	</select> 
	 
</mapper> 

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

package com.ys.test; 
 
import org.junit.Before; 
import org.junit.Test; 
import org.springframework.context.ApplicationContext; 
import org.springframework.context.support.ClassPathXmlApplicationContext; 
 
import com.ys.mapper.UserMapper; 
import com.ys.po.User; 
 
public class UserMapperTest { 
	 
	private ApplicationContext applicationContext; 
 
    @Before 
    public void setUp() throws Exception { 
        applicationContext = new ClassPathXmlApplicationContext("classpath:spring/applicationContext.xml");//得到spring容器 
    } 
 
    @Test 
    public void testSelectUserById() throws Exception { 
    	UserMapper userMapper = (UserMapper) applicationContext.getBean("userMapper"); 
    	User user = userMapper.selectUserById(1); 
    	System.out.println(user); 
     
    } 
 
} 

<!--第二种方式：mapper批量扫描 
		规范：mapper.java和mapper.xml必须在同一个包下，并没名称一致 
		bean的id为mapper类名（首字母小写） 
	  --> 
	<bean  class="org.mybatis.spring.mapper.MapperScannerConfigurer"> 
		<!-- 指定扫描的包名  
			如果扫描多个包，那么每个包中间使用半角逗号分隔 --> 
	    <property name="basePackage" value="com.ys.mapper"></property> 
	    <property name="sqlSessionFactoryBeanName" value="sqlSessionFactory" /> 
	</bean>