4.2.4 父子容器問題

• 問題

  按照現(xiàn)有父子工廠（容器）的開發(fā)方式，Service層沒有添加事務(wù)。

• 問題成因

  獲取的是子容器的UserService，而子容器中沒有事務(wù)配置，所以獲取不到事務(wù)。

• 解決方案

  之所以在子容器沒有實(shí)現(xiàn)事務(wù)，是因?yàn)榘鼟呙璧娜康陌?，將service的包也交給子容器管理。

  子容器：只掃描控制器及與MVC相關(guān)的內(nèi)容
  <context:component-scan base-package="com.baizhi.controller"/>
  
  父容器：不掃描控制器與MVC相關(guān)的內(nèi)容
  <context:component-scan base-package="com.baizhi">
      <context:exclude-filter type="aspectj" expression="com.baizhi.controller"/>
  </context:component-scan>
  注意：在SpingBoot中不會(huì)出現(xiàn)父子容器的問題。
  

4.3 SpringMVC控制器調(diào)用業(yè)務(wù)對(duì)象總結(jié)（SSM）

4.3.1 完整編碼總結(jié)

• web.xml

  <listener>
      <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
  </listener>
  <context-param>
      <param-name>contextConfigLocation</param-name>
      <param-value>classpath:applicationContext.xml</param-value>
  </context-param>
  
  <servlet>
      <servlet-name>dispatcherServlet</servlet-name>
      <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
      <init-param>
          <param-name>contextConfigLocation</param-name>
          <param-value>classpath:dispatcher.xml</param-value>
      </init-param>
      <load-on-startup>1</load-on-startup>
  </servlet>
  <servlet-mapping>
      <servlet-name>dispatcherServlet</servlet-name>
      <url-pattern>/</url-pattern>
  </servlet-mapping>
  
  <filter>
      <filter-name>encodingFilter</filter-name>
      <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
      <init-param>
          <param-name>encoding</param-name>
          <param-value>UTF-8</param-value>
      </init-param>
  </filter>
  <filter-mapping>
      <filter-name>encodingFilter</filter-name>
      <url-pattern>/*</url-pattern>
  </filter-mapping>
  

• dispatcher.xml

  <context:component-scan base-package="com.baizhi.controller"/>
  <mvc:annotation-driven/>
  
  <bean id="viewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver">
      <property name="prefix" value="/"/>
      <property name="suffix" value=".jsp"/>
  </bean>
  

• applicationContex.xml

  <context:component-scan base-package="com.baizhi">
      <context:exclude-filter type="aspectj" expression="com.baizhi.controller"/>
  </context:component-scan>
  <!--連接池-->
  <bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource">
      <property name="driverClassName" value="com.mysql.jdbc.Driver"/>
      <property name="url" value="jdbc:mysql://localhost:3306/myschool?useSSL=false&amp;allowPublicKeyRetrieval=true"/>
      <property name="username" value="root"/>
      <property name="password" value="123456"/>
  </bean>
  <!-- 創(chuàng)建SqlSessionFactory SqlSessionFactoryBean-->
  <bean id="sqlSessionFactoryBean" class="org.mybatis.spring.SqlSessionFactoryBean">
      <property name="dataSource" ref="dataSource"/>
      <property name="typeAliasesPackage" value="com.baizhi.entity"/>
      <property name="mapperLocations">
          <list>
              <value>classpath:com.baizhi.mapper/*Mapper.xml</value>
          </list>
      </property>
  </bean>
  <!--創(chuàng)建DAO對(duì)象 MapperScannerConfigure-->
  <bean id="scanner" class="org.mybatis.spring.mapper.MapperScannerConfigurer">
      <property name="sqlSessionFactoryBeanName" value="sqlSessionFactoryBean"/>
      <property name="basePackage" value="com.baizhi.dao"/>
  </bean>
  
  <!-- 配置事務(wù)-->
  <bean id="dataSourceTransactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
      <property name="dataSource" ref="dataSource"/>
  </bean>
  
  <tx:annotation-driven transaction-manager="dataSourceTransactionManager"/>
  

• DAO

  // **POJO**
  public class User implements Serializable {
      private Integer id;
      private String name;
      private String password;
  // **建表**
  create table t_user(
      id integer primary key auto_increment;
      name varchar(12),
      password varchar(12)
  );
  // **DAO**
  public interface UserDAO {
      void save(User user);
  }
  // **Mapper**
  <mapper namespace="com.baizhi.dao.UserDAO">
  
      <insert id="save">
          insert into admin(name,password) values(#{name},#{password})
      </insert>
  </mapper>
  

• Service

  public interface UserService {
      void register(User user);
  }
  
  Service
  @Transactional
  public class UserServiceImpl implements UserService {
  
      @Autowired
      private UserDAO userDAO;
  
      @Override
      public void register(User user) {
          userDAO.save(user);
      }
  }
  

• Controller

  @Controller
  @RequestMapping("/user")
  public class UserController {
  
      @Autowired
      private UserService userService;
  
      @RequestMapping("/register")
      public String register(User user) {
          userService.register(user);
          return "regOk";
      }
  }
  

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