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[Java教程]SpringMVC4 + Spring + MyBatis3 基于注解的最简配置


本文使用最新版本(4.1.5)的springmvc+spring+mybatis,采用最间的配置方式来进行搭建。

1. web.

我们知道springmvc是基于DispatcherServlet来分发请求的,所以先在web.

<??><web-app version="2.5"   ="http://java.sun.com/   ="http://www.w3.org/2001/   xsi:schemaLocation="http://java.sun.com/> <display-name>sp</display-name>  <servlet>   <servlet-name>dispatcherServlet</servlet-name>   <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>   <load-on-startup>1</load-on-startup>   <init-param>     <param-name>contextConfigLocation</param-name>     <param-value>classpath:config/spring-mvc.</param-value>   </init-param> </servlet> <servlet-mapping>   <servlet-name>dispatcherServlet</servlet-name>   <url-pattern>/</url-pattern> </servlet-mapping>  <listener>   <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class> </listener> <context-param>   <param-name>contextConfigLocation</param-name>   <param-value>classpath:config/applicationContext.</param-value> </context-param> </web-app>

servlet下面的init-param中的指定了springmvc的dispatcherServlet的配置文件:config/spring-mvc.getServletConfig().getInitParameter("paramName");  可以访问到init-param中指定的参数,从而可以读取到config/spring-mvc.

ContextLoaderListener是spring监听servlet容器的启动的,在servlet容器启动时,就初始化bean工厂,对bean进行初始化等等操作。context-param指定了spring的配置文件config/applicationContext.getServletContext().getInitParameter("paraName"); 读取到值。

2. springmvc.

下面我们看一下springmvc.

<?  ="http://www.springframework.org/schema/mvc"  ="http://www.w3.org/2001/  ="http://www.springframework.org/schema/context"  xsi:schemaLocation="    http://www.springframework.org/schema/beans    http://www.springframework.org/schema/beans/spring-beans.xsd    http://www.springframework.org/schema/mvc    http://www.springframework.org/schema/mvc/spring-mvc.xsd    http://www.springframework.org/schema/context    http://www.springframework.org/schema/context/spring-context.xsd">      <mvc:annotation-driven />  <context:component-scan base-package="net.aazj.controller" />     <bean id="viewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver">     <property name="prefix" value="/" />     <property name="suffix" value=".jsp" />   </bean>   // ... ...</beans>

启用注解驱动,并指定control的包路径,还有指定了视图解析器,so easy。

3. applicationContext.

spring中相关bean扫描,事物的配置,以及和mybatis的结合配置如下所示:

<?  ="http://www.w3.org/2001/  ="http://www.springframework.org/schema/p"  ="http://www.springframework.org/schema/tx"  ="http://www.springframework.org/schema/context"  xsi:schemaLocation="    http://www.springframework.org/schema/beans    http://www.springframework.org/schema/beans/spring-beans.xsd    http://www.springframework.org/schema/tx    http://www.springframework.org/schema/tx/spring-tx.xsd    http://www.springframework.org/schema/context    http://www.springframework.org/schema/context/spring-context.xsd">  <context:component-scan base-package="net.aazj.service" />  <!-- 引入属性文件 -->  <context:property-placeholder location="classpath:config/db.properties" />    <!-- 配置数据源 -->  <bean name="dataSource" class="com.alibaba.druid.pool.DruidDataSource" init-method="init" destroy-method="close">    <property name="url" value="${jdbc_url}" />    <property name="username" value="${jdbc_username}" />    <property name="password" value="${jdbc_password}" />    <!-- 初始化连接大小 -->    <property name="initialSize" value="0" />    <!-- 连接池最大使用连接数量 -->    <property name="maxActive" value="20" />    <!-- 连接池最大空闲 -->    <property name="maxIdle" value="20" />    <!-- 连接池最小空闲 -->    <property name="minIdle" value="0" />    <!-- 获取连接最大等待时间 -->    <property name="maxWait" value="60000" />  </bean>    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">   <property name="dataSource" ref="dataSource" />   <property name="configLocation" value="classpath:config/mybatis-config.for a single JDBC DataSource -->  <bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">    <property name="dataSource" ref="dataSource" />  </bean>    <!-- 使用annotation定义事务 -->  <tx:annotation-driven transaction-manager="transactionManager" />     <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">   <property name="basePackage" value="net.aazj.mapper" />  </bean></beans>

同样相关service bean也使用基于注解的扫描方式:context:component-scan,所以需要在serviceImpl相关类上和方法上使用@Transanctional注解类配置事物。

sqlSessionFactory的配置相当重要,configLocation指定了mybatis的配置文件,如果需要在mybatis配置文件中配置比如<settings>, <typeAliases>, <mappers>则,需要在这里指定,如果不需要就没有必要指定值了。mapperLocations指定了mapper接口映射sql语句的

4. mybatis-config.

spring和mybatis的接口,其实可以不需要mybatis-config.

<?DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN" "http://mybatis.org/dtd/mybatis-3-config.dtd"><configuration> <settings>   <setting name="cacheEnabled" value="true"/>   <setting name="lazyLoadingEnabled" value="true"/>   <setting name="multipleResultSetsEnabled" value="true"/>   <setting name="useColumnLabel" value="true"/>   <setting name="useGeneratedKeys" value="false"/>   <setting name="autoMappingBehavior" value="PARTIAL"/>   <setting name="defaultExecutorType" value="SIMPLE"/>   <setting name="defaultStatementTimeout" value="25"/>   <setting name="safeRowBoundsEnabled" value="false"/>   <setting name="mapUnderscoreToCamelCase" value="false"/>   <setting name="localCacheScope" value="SESSION"/>   <setting name="jdbcTypeForNull" value="OTHER"/>   <setting name="lazyLoadTriggerMethods" value="equals,clone,hashCode,toString"/> </settings> <typeAliases>   <package name="net.aazj.pojo"/> </typeAliases></configuration>

<settings>指定了数据库操作相关的设置,typeAliases指定了可以给数据库表对应的类所在的包路径,可以在sql的

package net.aazj.pojo;import org.apache.ibatis.type.Alias;@Alias("User")public class User {  private Integer id;  private String name;    // ... ...}

<?    select * from user where id = #{id}  </select>  <select id="addUser" parameterType="string">    insert into user(name) values(#{name})  </select></mapper>

这里 resultType="User" 不需要使用全限定类名。<cache />启用了基于namespace="net.aazj.mapper.UserMapper"的全局缓存。