SpringMVC4 + Spring + MyBatis3 基于注解的最简配置
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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.xml
我们知道springmvc是基于Servlet: DispatcherServlet来处理分发请求的,所以我们需要先在web.xml文件中配置DispatcherServlet,而Spring的启动则是使用了监听器,所以需要配置spring的监听器:
<?xml version="1.0" encoding="UTF-8"?> <web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"> <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.xml</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.xml</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.xml,所有springmvc相关的都在该文件中进行配置。在DispatcherServlet(其父类)中使用: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.xml文件。load-on-startup值为1指定了dispatcherServlet随servlet容器启动。
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.xml,可以使用: getServletContext().getInitParameter("paraName"); 读取到值。
注意:init-param 和 context-param 的区别,从名字上就可以看得出,后者是相对于整个web应用的,而前者是针对单个servlet的。
2. springmvc.xml
下面我们看一下springmvc.xml该如何配置:
<?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:mvc="http://www.springframework.org/schema/mvc" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="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>
启用注解驱动来扫描controller,并指定control的包路径,还有指定了视图解析器,so easy。
注:这里要特别注意,springmvc和spring的配置文件中都有context:component-scan,一个是扫描controller,一个时扫描service,在指定扫描路径时最好不要一样,不要让他们交叉扫描,不然会导致事务不能回滚的错误。如果一定要一样的话那么可以使用如下配置来进行排除:
<!-- springmvc的配置文件中不扫描带有@Service注解的类 --> <context:component-scan base-package="net.aazj"> <context:exclude-filter type="annotation" expression="org.springframework.stereotype.Service"/> </context:component-scan>
<!-- spring的配置文件中不扫描带有@Controller注解的类 --> <context:component-scan base-package="net.aazj"> <context:exclude-filter type="annotation" expression="org.springframework.stereotype.Controller"/> </context:component-scan>
3. applicationContext.xml
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:
<?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:p="http://www.springframework.org/schema/p" xmlns:tx="http://www.springframework.org/schema/tx" xmlns:context="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.xml" /> <property name="mapperLocations" value="classpath*:config/mappers/**/*.xml" /> </bean> <!-- Transaction manager 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,事务也使用注解来驱动:tx:annotation-driven,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xml文件的位置。MapperScannerConfigurer指定了mapper接口所在的包路径。
4. mybatis-config.xml
spring和mybatis的接口,其实可以不需要mybatis-config.xml文件的存在,只有在需要配置<settings>, <typeAliases>, <mappers>(其实mapper也一并也是在applicationContext.xml中进行配置)才需要mybatis-config.xml文件的存在:
<?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> <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xml使用它们的别名:
package net.aazj.pojo; import org.apache.ibatis.type.Alias; @Alias("User") public class User { private Integer id; private String name; // ... ... }
@Alias("User")注解了该pojo的别名,所以可以在xml文件中使用别名 User 来代替:net.aazj.pojo.User
<?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="net.aazj.mapper.UserMapper"> <cache /> <select id="getUser" resultType="User"> 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。
5. generatorConfig.xml
<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE generatorConfiguration PUBLIC "-//mybatis.org//DTD MyBatis Generator Configuration 1.0//EN" "http://mybatis.org/dtd/mybatis-generator-config_1_0.dtd"> <generatorConfiguration> <classPathEntry location="D:\java_libs\repository\mysql\mysql-connector-java\5.1.35\mysql-connector-java-5.1.35.jar" /> <context id="MySQLTables" targetRuntime="MyBatis3"> <jdbcConnection driverClass="com.mysql.jdbc.Driver" connectionURL="jdbc:mysql://localhost:3306/sy" userId="root" password="xxxxx"> </jdbcConnection> <javaTypeResolver > <property name="forceBigDecimals" value="false" /> </javaTypeResolver> <javaModelGenerator targetPackage="net.aazj.pojo" targetProject="sp\src\main\java"> <property name="enableSubPackages" value="true" /> <property name="trimStrings" value="true" /> </javaModelGenerator> <sqlMapGenerator targetPackage="config.mappers" targetProject="sp\src\main\resources"> <property name="enableSubPackages" value="true" /> </sqlMapGenerator> <javaClientGenerator type="XMLMAPPER" targetPackage="net.aazj.mapper" targetProject="sp\src\main\java"> <property name="enableSubPackages" value="true" /> </javaClientGenerator> <table schema="sy" tableName="tbug" domainObjectName="Bug" > <property name="useActualColumnNames" value="false"/> <generatedKey column="id" sqlStatement="mysql" identity="true" /> <!-- <columnOverride column="DATE_FIELD" property="startDate" /> <ignoreColumn column="FRED" /> <columnOverride column="LONG_VARCHAR_FIELD" jdbcType="VARCHAR" /> --> </table> <table schema="sy" tableName="user" domainObjectName="User" > <property name="useActualColumnNames" value="false"/> <generatedKey column="id" sqlStatement="mysql" identity="true" /> </table> </context> </generatorConfiguration>
上面是Mybatis generator的配置文件:
1)classPathEntry 指定驱动位置;
2)jdbcConnection 指定数据库连接信息;
3)javaModelGenerator 指定生成的pojo类的位置;
4)sqlMapGenerator 指定指定生成的sql xml文件的位置;
5)javaClientGenerator 指定 mapper 接口的位置;
6)table 指定将数据库中哪些表进行处理;<generatedKey column="id" sqlStatement="mysql" identity="true" /> 用于指定主键;
6. 补上spring+mybatis多数据源的配置
其实很简单,就是需要将涉及到数据库,事物等相关的配置配置两份就行了,下面是修改之后的applicaitonContext.xml:
<?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:p="http://www.springframework.org/schema/p" xmlns:tx="http://www.springframework.org/schema/tx" xmlns:context="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.xml" /> <property name="mapperLocations" value="classpath*:config/mappers/**/*.xml" /> </bean> <!-- Transaction manager 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" /> <property name="sqlSessionFactoryBeanName" value="sqlSessionFactory"/> </bean> <!-- ===============第二个数据源的配置=============== --> <bean name="dataSource_slave" class="com.alibaba.druid.pool.DruidDataSource" init-method="init" destroy-method="close"> <property name="url" value="${jdbc_url_slave}" /> <property name="username" value="${jdbc_username_slave}" /> <property name="password" value="${jdbc_password_slave}" /> <!-- 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_slave" class="org.mybatis.spring.SqlSessionFactoryBean"> <property name="dataSource" ref="dataSource_slave" /> <property name="configLocation" value="classpath:config/mybatis-config-slave.xml" /> <property name="mapperLocations" value="classpath*:config/mappers/slave/**/*.xml" /> </bean> <!-- Transaction manager for a single JDBC DataSource --> <bean id="transactionManager_slave" class="org.springframework.jdbc.datasource.DataSourceTransactionManager"> <property name="dataSource" ref="dataSource_slave" /> </bean> <!-- 使用annotation定义事务 --> <tx:annotation-driven transaction-manager="transactionManager_slave" /> <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer"> <property name="basePackage" value="net.aazj.mapper.slave" /> <property name="sqlSessionFactoryBeanName" value="sqlSessionFactory_slave"/> </bean> </beans>
主要是注意在两个MapperScannerConfigurer中都通过sqlSessionFactoryBeanName指定了sqlSessionFactory。这样的话,在mapper接口中注入的就是不同的sqlSessionFactory,而不同的sqlSessionFactory又引用不同的dataSource和不同的configLocation,以及不同的mapperLocations。而MapperScannerConfigurer在扫描mapper接口所在的包路径时,会将其装配成bean。所以我们可以在serviceImpl中使用@Autowired等注解来引用:
@Service("userService") @Transactional public class UserServiceImpl implements UserService{ @Autowired private UserMapper userMapper; // ... ... }
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