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 程式師世界 >> 編程語言 >> JAVA編程 >> JAVA綜合教程 >> SpringMVC4 + Spring + MyBatis3 基於注解的最簡配置,springmvc4mybatis3

SpringMVC4 + Spring + MyBatis3 基於注解的最簡配置,springmvc4mybatis3

編輯:JAVA綜合教程

SpringMVC4 + Spring + MyBatis3 基於注解的最簡配置,springmvc4mybatis3


本文使用最新版本(4.1.5)的springmvc+spring+mybatis,采用最間的配置方式來進行搭建。

1. web.xml

我們知道springmvc是基於Servlet: DispatcherServlet來處理分發請求的,所以我們需要先在web.xml文件中配置DispatcherServlet,而Spring的啟動則是使用了監聽器,所以需要配置spring的監聽器:

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<?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>
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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相關的都在該文件中進行配置。在DispatcherServlet(其父類)中使用:getServletConfig().getInitParameter("paramName");  可以訪問到init-param中指定的參數,從而可以讀取到config/spring-mvc.xml文件。load-on-startup值為1指定了dispatcherServlet隨servlet容器啟動。

ContextLoaderListener是spring監聽servlet容器的啟動的,在servlet容器啟動時,就初始化bean工廠,對bean進行初始化等等操作。context-param指定了spring的配置文件config/applicationContext.xml,可以使用: getServletContext().getInitParameter("paraName"); 讀取到值。

注意:init-param 和 context-param 的區別,從名字上就可以看得出,後者是相對於整個web應用的,而前者是針對單個servlet的。

2. springmvc.xml

下面我們看一下springmvc.xml該如何配置:

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<?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>
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啟用注解驅動來掃描controller,並指定control的包路徑,還有指定了視圖解析器,so easy。

:這裡要特別注意,springmvc和spring的配置文件中都有context:component-scan,一個是掃描controller,一個時掃描service,在指定掃描路徑時最好不要一樣,不要讓他們交叉掃描,不然會導致事務不能回滾的錯誤。如果一定要一樣的話那麼可以使用如下配置來進行排除:

<!-- springmvc的配置文件中不掃描帶有@Service注解的類 -->
    <context:component-scan base-package="net.aazj">
        <context:exclude-filter type="annotation" expression="org.springframework.stereotype.Service"/>
    </context:component-scan>

 

<!-- spring的配置文件中不掃描帶有@Controller注解的類  -->
    <context:component-scan base-package="net.aazj">
        <context:exclude-filter type="annotation" expression="org.springframework.stereotype.Controller"/> 
    </context:component-scan>

 3. applicationContext.xml

spring中相關bean掃描,事物的配置,以及和mybatis的結合配置如下所示:

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<?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" />
    <!-- 引入屬性文件 -->
    <context:property-placeholder location="classpath:config/db.properties" />
    
    <!-- 配置數據源 -->
    <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}" />
        <!-- 初始化連接大小 -->
        <property name="initialSize" value="0" />
        <!-- 連接池最大使用連接數量 -->
        <property name="maxActive" value="20" />
        <!-- 連接池最大空閒 -->
        <property name="maxIdle" value="20" />
        <!-- 連接池最小空閒 -->
        <property name="minIdle" value="0" />
        <!-- 獲取連接最大等待時間 -->
        <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定義事務 -->
    <tx:annotation-driven transaction-manager="transactionManager" /> 
    
    <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
      <property name="basePackage" value="net.aazj.mapper" />
    </bean>
</beans>
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同樣相關service bean也使用基於注解的掃描方式:context:component-scan,事務也使用注解來驅動:tx:annotation-driven,所以需要在serviceImpl相關類上和方法上使用@Transanctional注解類配置事物。

sqlSessionFactory的配置相當重要,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>則,需要在這裡指定,如果不需要就沒有必要指定值了。mapperLocations指定了mapper接口映射sql語句的xml文件的位置。MapperScannerConfigurer指定了mapper接口所在的包路徑。

4. mybatis-config.xml

spring和mybatis的接口,其實可以不需要mybatis-config.xml文件的存在,只有在需要配置<settings>, <typeAliases>, <mappers>(其實mapper也一並也是在applicationContext.xml中進行配置)才需要mybatis-config.xml文件的存在:

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<?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>
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<settings>指定了數據庫操作相關的設置,typeAliases指定了可以給數據庫表對應的類所在的包路徑,可以在sql的xml使用它們的別名:

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package net.aazj.pojo;

import org.apache.ibatis.type.Alias;

@Alias("User")
public class User {

    private Integer id;

    private String name;

        // ... ...

}
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@Alias("User")注解了該pojo的別名,所以可以在xml文件中使用別名 User 來代替:net.aazj.pojo.User

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<?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>
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這裡 resultType="User" 不需要使用全限定類名。<cache />啟用了基於namespace="net.aazj.mapper.UserMapper"的全局緩存。

5. generatorConfig.xml

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<?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>
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上面是Mybatis generator的配置文件:

1)classPathEntry  指定驅動位置;

2)jdbcConnection 指定數據庫連接信息;

3)javaModelGenerator 指定生成的pojo類的位置;

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 指定將數據庫中哪些表進行處理;<generatedKey column="id" sqlStatement="mysql" identity="true" /> 用於指定主鍵;

6. 補上spring+mybatis多數據源的配置

其實很簡單,就是需要將涉及到數據庫,事物等相關的配置配置兩份就行了,下面是修改之後的applicaitonContext.xml:

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<?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" />
    <!-- 引入屬性文件 -->
    <context:property-placeholder location="classpath:config/db.properties" />
    
    <!-- 配置數據源 -->
    <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}" />
        <!-- 初始化連接大小 -->
        <property name="initialSize" value="0" />
        <!-- 連接池最大使用連接數量 -->
        <property name="maxActive" value="20" />
        <!-- 連接池最大空閒 -->
        <property name="maxIdle" value="20" />
        <!-- 連接池最小空閒 -->
        <property name="minIdle" value="0" />
        <!-- 獲取連接最大等待時間 -->
        <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定義事務 -->
    <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>
    
    <!-- ===============第二個數據源的配置=============== -->
    <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}" />
        <!-- 初始化連接大小 -->
        <property name="initialSize" value="0" />
        <!-- 連接池最大使用連接數量 -->
        <property name="maxActive" value="20" />
        <!-- 連接池最大空閒 -->
        <property name="maxIdle" value="20" />
        <!-- 連接池最小空閒 -->
        <property name="minIdle" value="0" />
        <!-- 獲取連接最大等待時間 -->
        <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定義事務 -->
    <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>
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主要是注意在兩個MapperScannerConfigurer中都通過sqlSessionFactoryBeanName指定了sqlSessionFactory。這樣的話,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在掃描mapper接口所在的包路徑時,會將其裝配成bean。所以我們可以在serviceImpl中使用@Autowired等注解來引用:

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@Service("userService")
@Transactional
public class UserServiceImpl implements UserService{
    @Autowired
    private UserMapper userMapper;

        // ... ...
}
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