Spring MVC学习随笔-控制器(Controller)开发详解：调用业务对象、父子工厂拆分（applicationContext.xml、dispatcher.xml）
学习视频：孙哥说SpringMVC：结合Thymeleaf，重塑你的MVC世界！｜前所未有的Web开发探索之旅
第四章、SpringMVC控制器开发详解 二
4.1 核心要点
4.2 SpringMVC控制器调用业务对象【SSM整合】
4.2.1 核心思路分析
4.2.2 编码
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dispatcher.xml
<context:component-scan base-package="com.baizhi"/> <mvc:annotation-driven/> <bean id="viewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver"> <property name="prefix" value="/"/> <property name="suffix" value=".jsp"/> bean> <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&allowPublicKeyRetrieval=true"/> <property name="username" value="root"/> <property name="password" value="123456"/> bean> <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.xmlvalue> list> property> bean> <bean id="scanner" class="org.mybatis.spring.mapper.MapperScannerConfigurer"> <property name="sqlSessionFactoryBeanName" value="sqlSessionFactoryBean"/> <property name="basePackage" value="com.baizhi.dao"/> bean> <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"; } }
4.2.3 父子工厂（父子容器） 拆分
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现有SSM开发中存在的问题
MVC层的对象（Controller，mvc:annotation-driven/,视图解析器）与非MVC层的（连接池 DAO Service 事务），都配置在dispatcher.xml中，最终交给DispatcherServlet创建的工厂来进行实例化，存在着耦合问题，后续一旦替换MVC的实现，代码会受到影响，不利于项目的维护
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如何解决
将非MVC的配置放在applicationContext.xml(引入ContextLoaderListener工厂读取配置)
- 把目前单一的工厂进行父子工厂的拆分
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子工厂（DispatcherServlet）读取dispatcher.xml
完成与SpringMVC相关对象的创建：视图解析器、自定义类型转换器、拦截器等
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父工厂（ContextLoaderListener）读取applicationContext.xml
完成与非SpringMVC相关对象的创建：连接池、DAO、Service、事务、Redis、ES、MQ等
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- 工厂（容器）在需要获取对象进行操作时，首先获取子容器所创建的对象，如果没有则继续获得父容器所创建的对象
- 把目前单一的工厂进行父子工厂的拆分
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编码
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子工厂（子容器）
# dispatcher.xml # SpringMVC相关的配置 <context:component-scan base-package="com.baizhi"/> <mvc:annotation-driven/> <bean id="viewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver"> <property name="prefix" value="/"/> <property name="suffix" value=".jsp"/> bean> # web.xml子容器的配置 <servlet> <servlet-name>dispatcherServletservlet-name> <servlet-class>org.springframework.web.servlet.DispatcherServletservlet-class> <init-param> <param-name>contextConfigLocationparam-name> <param-value>classpath:dispatcher.xmlparam-value> init-param> <load-on-startup>1load-on-startup> servlet> <servlet-mapping> <servlet-name>dispatcherServletservlet-name> <url-pattern>/url-pattern> servlet-mapping> -
父工厂（父容器）
# applicationContext.xml # Spring相关配置 <context:component-scan base-package="com.baizhi"/> <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&allowPublicKeyRetrieval=true"/> <property name="username" value="root"/> <property name="password" value="123456"/> bean> <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.xmlvalue> list> property> bean> <bean id="scanner" class="org.mybatis.spring.mapper.MapperScannerConfigurer"> <property name="sqlSessionFactoryBeanName" value="sqlSessionFactoryBean"/> <property name="basePackage" value="com.baizhi.dao"/> bean> <bean id="dataSourceTransactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager"> <property name="dataSource" ref="dataSource"/> bean> <tx:annotation-driven transaction-manager="dataSourceTransactionManager"/> # web.xml父容器的配置 <listener> <listener-class>org.springframework.web.context.ContextLoaderListenerlistener-class> listener> <context-param> <param-name>contextConfigLocationparam-name> <param-value>classpath:applicationContext.xmlparam-value> context-param>
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4.2.4 父子容器问题
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问题
按照现有父子工厂（容器）的开发方式，Service层没有添加事务。
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问题成因
获取的是子容器的UserService，而子容器中没有事务配置，所以获取不到事务。
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解决方案
之所以在子容器没有实现事务，是因为包扫描的全部的包，将service的包也交给子容器管理。
子容器：只扫描控制器及与MVC相关的内容 <context:component-scan base-package="com.baizhi.controller"/> 父容器：不扫描控制器与MVC相关的内容 <context:component-scan base-package="com.baizhi"> <context:exclude-filter type="aspectj" expression="com.baizhi.controller"/> context:component-scan> 注意：在SpingBoot中不会出现父子容器的问题。
4.3 SpringMVC控制器调用业务对象总结（SSM）
4.3.1 完整编码总结
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web.xml
<listener> <listener-class>org.springframework.web.context.ContextLoaderListenerlistener-class> listener> <context-param> <param-name>contextConfigLocationparam-name> <param-value>classpath:applicationContext.xmlparam-value> context-param> <servlet> <servlet-name>dispatcherServletservlet-name> <servlet-class>org.springframework.web.servlet.DispatcherServletservlet-class> <init-param> <param-name>contextConfigLocationparam-name> <param-value>classpath:dispatcher.xmlparam-value> init-param> <load-on-startup>1load-on-startup> servlet> <servlet-mapping> <servlet-name>dispatcherServletservlet-name> <url-pattern>/url-pattern> servlet-mapping> <filter> <filter-name>encodingFilterfilter-name> <filter-class>org.springframework.web.filter.CharacterEncodingFilterfilter-class> <init-param> <param-name>encodingparam-name> <param-value>UTF-8param-value> init-param> filter> <filter-mapping> <filter-name>encodingFilterfilter-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> <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&allowPublicKeyRetrieval=true"/> <property name="username" value="root"/> <property name="password" value="123456"/> bean> <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.xmlvalue> list> property> bean> <bean id="scanner" class="org.mybatis.spring.mapper.MapperScannerConfigurer"> <property name="sqlSessionFactoryBeanName" value="sqlSessionFactoryBean"/> <property name="basePackage" value="com.baizhi.dao"/> bean> <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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