framework学习笔记day09---Spring-Mybatis整合、web

事务的回滚和不回滚的异常

• 概述

  • 默认情况，遇到运行时异常回滚，遇到编译期异常不回滚。
  • rollbackFor设置需要回滚的异常
  • noRollbackFor设置不需要回滚的异常

• 代码实现

  //@Transactional(rollbackFor = FileNotFoundException.class,noRollbackFor = ArithmeticException.class)
  @Transactional(rollbackFor = Exception.class)
  @Override
  public void addUser(User inputUser) throws Exception {
      System.out.println("UserServiceImpl addUser");
      userDao.addUser(inputUser);
      //运行时异常，会回滚
      System.out.println(1 / 0);
      //编译期异常
      //new FileInputStream("a");
  
  }
  

事务的隔离级别

• 隔离级别

  • 读未提交：可以读取到事务未提交的数据
  • 读已提交：可以读取到事务中的数据前后不一致
  • 可重复读：查询事务中的数据(id=1)不存在，添加该数据(id=1)已存在
  • 串行化：效率低

• 代码实现

  @Transactional(isolation = Isolation.REPEATABLE_READ)
  @Override
  public void addUser(User inputUser) throws Exception {
      System.out.println("UserServiceImpl addUser");
      userDao.addUser(inputUser);
      //运行时异常，会回滚
      System.out.println(1 / 0);
      //编译期异常
      //new FileInputStream("a");
  }
  
  @Transactional(isolation = Isolation.REPEATABLE_READ)
  @Override
  public List selectUserList() throws Exception {
      List userList = userDao.selectUserList();
      userList = userDao.selectUserList();
      return userList;
  }
  

事务传播行为(难点)

• 概述
  • 
  • 规定管理员中的事务和协调员中的事务的关系。
• 传播行为
  • 

事务传播行为演示(难点)

• 需求

  • 进行转账业务时，进行日志记录。

• REQUIRED

  //事务管理员
  @Transactional(isolation = Isolation.REPEATABLE_READ)
  @Override
  public List<User> selectUserList() throws Exception {
      List<User> userList = userDao.selectUserList();
      userList = userDao.selectUserList();
      return userList;
  }
  

  //事务协调员
  @Transactional(propagation = Propagation.REQUIRED)
  @Override
  public void addLog(String content) throws Exception {
      logDao.addLog(content);
      System.out.println(1 / 0);
  }
  

• 注意事项

  • 传播行为应该在协调员进行设置.

Spring整合MyBatis概述

• 概述
  • 将mybatis容器交给spring容器管理
• 传统dao开发
  • dao接口 + dao实现子类 + mapper映射文件 + spring容器
  • 本质是将dao实现子类交给spring容器管理
• 接口代理开发
  • dao接口 + mapper映射文件 + spring容器
  • 本质是将dao接口代理对象交给spring容器管理

Spring整合MyBatis之传统dao开发

• 概述

  • 本质将dao实现子类交给Spring容器管理

• 开发步骤

  • ①引入相关依赖
  • ②定义service及其实现子类
  • ③定义dao及其实现子类
  • ④编写spring-core.xml
    • 扫描注解
    • 将SqlSessionFactory对象交给Spring容器管理(使用SqlSessionFactoryBean)，FactoryBean机制
      • 加载mybatis核心配置文件SqlMapConfig.xml
    • 将DruidDataSource对象交给Spring容器管理
  • ⑤代码测试

• ①引入相关依赖

  <properties>
      <maven.compiler.source>8maven.compiler.source>
      <maven.compiler.target>8maven.compiler.target>
      <junit.version>4.13.2junit.version>
      <lombok.version>1.18.22lombok.version>
      <spring.version>5.3.13spring.version>
      <dbutils.version>1.7dbutils.version>
      <druid.version>1.2.8druid.version>
      <mysql.version>5.1.48mysql.version>
      <mybatis.version>3.5.7mybatis.version>
      <mybatis-spring.version>2.0.6mybatis-spring.version>
  properties>
  
  <dependencies>
  
      
      <dependency>
          <groupId>junitgroupId>
          <artifactId>junitartifactId>
          <version>${junit.version}version>
          <scope>testscope>
      dependency>
      
  
      
      <dependency>
          <groupId>org.projectlombokgroupId>
          <artifactId>lombokartifactId>
          <version>${lombok.version}version>
      dependency>
      
  
      
      <dependency>
          <groupId>org.springframeworkgroupId>
          <artifactId>spring-coreartifactId>
          <version>${spring.version}version>
      dependency>
      <dependency>
          <groupId>org.springframeworkgroupId>
          <artifactId>spring-beansartifactId>
          <version>${spring.version}version>
      dependency>
      <dependency>
          <groupId>org.springframeworkgroupId>
          <artifactId>spring-contextartifactId>
          <version>${spring.version}version>
      dependency>
      <dependency>
          <groupId>org.springframeworkgroupId>
          <artifactId>spring-expressionartifactId>
          <version>${spring.version}version>
      dependency>
  
      <dependency>
          <groupId>org.springframeworkgroupId>
          <artifactId>spring-testartifactId>
          <version>${spring.version}version>
      dependency>
  
      <dependency>
          <groupId>org.springframeworkgroupId>
          <artifactId>spring-jclartifactId>
          <version>${spring.version}version>
      dependency>
  
      <dependency>
          <groupId>org.springframeworkgroupId>
          <artifactId>spring-aopartifactId>
          <version>${spring.version}version>
      dependency>
  
      <dependency>
          <groupId>org.springframeworkgroupId>
          <artifactId>spring-aspectsartifactId>
          <version>${spring.version}version>
      dependency>
  
      <dependency>
          <groupId>org.springframeworkgroupId>
          <artifactId>spring-jdbcartifactId>
          <version>${spring.version}version>
      dependency>
  
      <dependency>
          <groupId>org.springframeworkgroupId>
          <artifactId>spring-txartifactId>
          <version>${spring.version}version>
      dependency>
      
  
  
      
      <dependency>
          <groupId>org.mybatisgroupId>
          <artifactId>mybatis-springartifactId>
          <version>${mybatis-spring.version}version>
      dependency>
      
  
  
      
      <dependency>
          <groupId>org.mybatisgroupId>
          <artifactId>mybatisartifactId>
          <version>${mybatis.version}version>
      dependency>
      
  
      
      <dependency>
          <groupId>com.alibabagroupId>
          <artifactId>druidartifactId>
          <version>${druid.version}version>
      dependency>
      <dependency>
          <groupId>mysqlgroupId>
          <artifactId>mysql-connector-javaartifactId>
          <version>${mysql.version}version>
      dependency>
      
  
  dependencies>
  

• ②定义service及其实现子类

  @Service
  public class UserServiceImpl implements UserService {
  
      @Autowired
      private UserDao userDao;
  
      @Override
      public List<User> selectUserList() throws Exception {
          return userDao.selectUserList();
      }
  }
  

• ③定义dao及其实现子类

  @Repository
  public class UserDaoImpl implements UserDao {
  
      @Autowired
      private SqlSessionFactory sqlSessionFactory;
      @Override
      public List<User> selectUserList() throws Exception {
          SqlSession sqlSession = sqlSessionFactory.openSession();
          List<User> userList = sqlSession.selectList("selectUserList");
          sqlSession.close();
          return userList;
      }
  
  }
  

• ④编写spring-core.xml

  
  <beans xmlns="http://www.springframework.org/schema/beans"
         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/context https://www.springframework.org/schema/context/spring-context.xsd">
  
      
      <context:component-scan base-package="com.atguigu">context:component-scan>
  
      <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
          <property name="dataSource" ref="dataSource">property>
          
          <property name="configLocation" value="SqlMapConfig.xml">property>
      bean>
  
      <context:property-placeholder location="jdbc.properties">context:property-placeholder>
      <bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource">
          <property name="driverClassName" value="${driverClass}">property>
          <property name="url" value="${url}">property>
          <property name="username" value="${user}">property>
          <property name="password" value="${password}">property>
      bean>
  
  beans>
  

• ⑤代码测试

  public class UserController {
  
      public static void main(String[] args) throws Exception {
          //Spring容器初始化
          ApplicationContext applicationContext = new ClassPathXmlApplicationContext("spring-core.xml");
  
          UserService userService = applicationContext.getBean(UserService.class);
          List<User> userList = userService.selectUserList();
          System.out.println("userList = " + userList);
      }
  
  }
  

  @RunWith(SpringJUnit4ClassRunner.class)
  @ContextConfiguration(locations = "classpath:spring-core.xml")
  public class UserServiceTest {
  
      @Autowired
      private UserService userService;
      @Test
      public void selectUserList() throws Exception {
          List<User> userList = userService.selectUserList();
          System.out.println("userList = " + userList);
      }
  }
  

• 存在问题

  • 每次都需要通过SqlSessionFactory获取SqlSession对象并使用，结束后还得关闭，比较麻烦。

Spring整合MyBatis之传统dao开发优化

• 概述

  • 使用SqlSessionDaoSupport类

• 优化一

  @Repository
  public class UserDaoImpl extends SqlSessionDaoSupport implements UserDao {
  
  
      //给UserDaoImpl的父类SqlSessionDaoSupport注入SqlSessionFactory对象
      @Autowired
      @Override
      public void setSqlSessionFactory(SqlSessionFactory sqlSessionFactory) {
          super.setSqlSessionFactory(sqlSessionFactory);
      }
  
      @Override
      public List<User> selectUserList() throws Exception {
          List<User> userList = getSqlSession().selectList("selectUserList");
          return userList;
      }
  
  }
  

• 优化二

  public class BaseDao extends SqlSessionDaoSupport {
  
      @Autowired
      @Override
      public void setSqlSessionFactory(SqlSessionFactory sqlSessionFactory) {
          super.setSqlSessionFactory(sqlSessionFactory);
      }
  }
  

  @Repository
  public class UserDaoImpl extends BaseDao implements UserDao {
  
  
      @Override
      public List<User> selectUserList() throws Exception {
          List<User> userList = getSqlSession().selectList("selectUserList");
          return userList;
      }
  
  }
  

Spring整合MyBatis之接口代理

• 概述

  • 本质将接口代理对象交给Spring容器管理

• 开发步骤

  • ①定义service接口及其实现子类
  • ②定义dao接口
  • ③编写spring-core.xml
    • 扫描注解
    • 将dao接口代理类对象放入Spring容器(使用MapperFactoryBean)
    • 将SqlSessionFactory对象放入Spring容器(使用SqlSessionFactoryBean)
    • 将DruidDataSource对象放入到Spring容器
  • ④代码测试

• ①定义service接口及其实现子类

• ②定义dao接口

• ③编写spring-core.xml

  
  <beans xmlns="http://www.springframework.org/schema/beans"
         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/context https://www.springframework.org/schema/context/spring-context.xsd">
  
      
      <context:component-scan base-package="com.atguigu">context:component-scan>
  
      
      <bean class="org.mybatis.spring.mapper.MapperFactoryBean">
          <property name="mapperInterface" value="com.atguigu.mapper.UserMapper">property>
          <property name="sqlSessionFactory" ref="sqlSessionFactory">property>
      bean>
  
      <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
          <property name="dataSource" ref="dataSource">property>
          <property name="configLocation" value="SqlMapConfig.xml">property>
      bean>
  
  
      <context:property-placeholder location="jdbc.properties">context:property-placeholder>
      <bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource">
          <property name="driverClassName" value="${driverClass}">property>
          <property name="url" value="${url}">property>
          <property name="username" value="${user}">property>
          <property name="password" value="${password}">property>
      bean>
  
  beans>
  

• ④代码测试

• 存在问题

  • ①在SqlMapConfig.xml文件中，不需要再通过标签加载映射文件
  • ②如果有100个mapper接口，那么就需要写100次将mapper接口代理类对象放入到Spring容器，过于麻烦。

Spring整合MyBatis之接口代理优化

• 概述

  • 使用MapperScannerConfigurer

• 代码实现

  
  <beans xmlns="http://www.springframework.org/schema/beans"
         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/context https://www.springframework.org/schema/context/spring-context.xsd">
  
      
      <context:component-scan base-package="com.atguigu">context:component-scan>
  
      
      <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
          <property name="basePackage" value="com.atguigu.mapper">property>
      bean>
  
      <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
          <property name="dataSource" ref="dataSource">property>
          <property name="configLocation" value="SqlMapConfig.xml">property>
      bean>
  
  
      <context:property-placeholder location="jdbc.properties">context:property-placeholder>
      <bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource">
          <property name="driverClassName" value="${driverClass}">property>
          <property name="url" value="${url}">property>
          <property name="username" value="${user}">property>
          <property name="password" value="${password}">property>
      bean>
  
  beans>
  

Spring整合MyBatis引入logback

• 开发步骤

  • ①引入相关依赖
  • ②编写logback.xml
  • ③代码测试

• ①引入相关依赖

  <dependency>
      <groupId>ch.qos.logbackgroupId>
      <artifactId>logback-classicartifactId>
      <version>1.2.7version>
  dependency>
  <dependency>
      <groupId>org.slf4jgroupId>
      <artifactId>slf4j-apiartifactId>
      <version>1.7.32version>
  dependency>
  

• ②编写logback.xml

  
  <configuration debug="true">
      
      <appender name="STDOUT"
                class="ch.qos.logback.core.ConsoleAppender">
          <encoder>
              
              
              <pattern>[%d{HH:mm:ss.SSS}] [%-5level] [%thread] [%logger] [%msg]%npattern>
          encoder>
      appender>
  
      
      
      <root level="INFO">
          
          <appender-ref ref="STDOUT"/>
      root>
  
      <logger name="java.sql">
          <level value="debug"/>
      logger>
  
      <logger name="org.apache.ibatis">
          <level value="info"/>
      logger>
  
      <logger name="com.atguigu.controller.UserController">
          <level value="debug"/>
      logger>
  
  
  configuration>
  

• ③代码测试

  public class UserController {
  
      public static Logger logger = LoggerFactory.getLogger(UserController.class);
  
      public static void main(String[] args) throws Exception {
          //Spring容器初始化
          ApplicationContext applicationContext = new ClassPathXmlApplicationContext("spring-core.xml");
  
          UserService userService = applicationContext.getBean(UserService.class);
          List<User> userList = userService.selectUserList();
          logger.debug("userList : " + userList);
      }
  
  }
  

Spring整合MyBatis引入分页插件

• 开发步骤

  • ①引入相关依赖
  • ②编写UserService
  • ③编写SqlMapConfig.xml
    • 配置PageInterceptor
  • ④代码测试

• ①引入相关依赖

  <dependency>
      <groupId>com.github.pagehelpergroupId>
      <artifactId>pagehelperartifactId>
      <version>5.2.1version>
  dependency>
  

• ②编写UserService

  @Service
  public class UserServiceImpl implements UserService {
  
      @Autowired
      private UserMapper userMapper;
  
  
      @Override
      public PageInfo<User> selectUserListByPage(Integer currentPage, Integer pageSize) throws Exception {
          PageHelper.startPage(currentPage,pageSize);
          List<User> userList = userMapper.selectUserList();
          return new PageInfo<>(userList);
      }
  }
  

• ③编写SqlMapConfig.xml

  <plugins>
      <plugin interceptor="com.github.pagehelper.PageInterceptor">
          <property name="reasonable" value="true"/>
      plugin>
  plugins>
  

Spring整合MyBatis引入事务管理

• 开发步骤

  • ①编写spring-core.xml
    • 开启支持事务注解
  • ②编写UserService
    • 使用@Transactional注解

• ①编写spring-core.xml

  
  <tx:annotation-driven transaction-manager="transactionManager">tx:annotation-driven>
  
  <bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
      <property name="dataSource" ref="dataSource">property>
  bean>
  

• ②编写UserService

  @Transactional
  @Service
  public class UserServiceImpl implements UserService {
  
      @Autowired
      private UserMapper userMapper;
  
      @Override
      public void addUser(User inputUser) throws Exception {
          userMapper.addUser(inputUser);
          System.out.println(1 / 0);
      }
  
      @Override
      public List<User> selectUserList() throws Exception {
          return userMapper.selectUserList();
      }
  
      @Override
      public PageInfo<User> selectUserListByPage(Integer currentPage, Integer pageSize) throws Exception {
          PageHelper.startPage(currentPage, pageSize);
          List<User> userList = userMapper.selectUserList();
          return new PageInfo<>(userList);
      }
  }
  

Spring整合web环境第一版

• 需求

  • 在JavaWeb程序中使用Spring容器（在UserServlet中使用Spring容器中的UserService对象）

• 开发步骤

  • ①创建web项目
  • ②Spring整合MyBatis
  • ③编写UserController

• ①创建web项目

• ②Spring整合MyBatis

• ③编写UserController

  @WebServlet("/selectUserList")
  public class UserController extends HttpServlet {
  
  
      @Override
      protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
          //初始化Spring容器
          ApplicationContext applicationContext = new ClassPathXmlApplicationContext("spring-core.xml");
          UserService userService = applicationContext.getBean(UserService.class);
          try {
              //使用Spring容器中的UserService对象
              List<User> userList = userService.selectUserList();
              System.out.println("userList = " + userList);
          } catch (Exception e) {
              e.printStackTrace();
          }
      }
  
      @Override
      protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
          doGet(req, resp);
      }
  }
  

• 存在问题

  • 发起一次请求UserController，就会创建一次Spring容器。

Spring整合web环境第二版

• 概述

  • Spring容器只需要初始化一次，在后续的操作中都能够一直被使用。

• 解决方案

  • 服务器启动，项目启动，就初始化Spring容器，使用ServletContextListener监听器；

• 代码实现

  public class MyContextLoaderListener implements ServletContextListener {
  
      @Override
      public void contextInitialized(ServletContextEvent sce) {
          //项目启动，初始化Spring容器
          ApplicationContext applicationContext = new ClassPathXmlApplicationContext("spring-core.xml");
          sce.getServletContext().setAttribute("applicationContext", applicationContext);
      }
  
      @Override
      public void contextDestroyed(ServletContextEvent sce) {
          //项目销毁
      }
  }
  

  <listener>
      <listener-class>com.atguigu.listenter.MyContextLoaderListenerlistener-class>
  listener>
  

  @WebServlet("/selectUserList")
  public class UserController extends HttpServlet {
  
  
      @Override
      protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
          //初始化Spring容器
          //ApplicationContext applicationContext = new ClassPathXmlApplicationContext("spring-core.xml");
          ApplicationContext applicationContext = (ApplicationContext) getServletContext().getAttribute("applicationContext");
          UserService userService = applicationContext.getBean(UserService.class);
          try {
              //使用Spring容器中的UserService对象
              List<User> userList = userService.selectUserList();
              System.out.println("userList = " + userList);
          } catch (Exception e) {
              e.printStackTrace();
          }
      }
  
      @Override
      protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
          doGet(req, resp);
      }
  }
  

• 存在问题

  • 存在"spring-core.xml"、"applicationContext"字符串硬编码问题。

Spring整合Web环境第三版

• 概述

  • 将"spring-core.xml"设置web.xml中；
  • 将"applicationContext"放入到工具类中

• 代码实现

  <web-app>
      <display-name>Archetype Created Web Applicationdisplay-name>
  
      
      <context-param>
          <param-name>contextConfigLocationparam-name>
          <param-value>classpath:spring-core.xmlparam-value>
      context-param>
  
      <listener>
          <listener-class>com.atguigu.listenter.MyContextLoaderListenerlistener-class>
      listener>
  
  
  web-app>
  

  public class MyContextLoaderListener implements ServletContextListener {
  
      @Override
      public void contextInitialized(ServletContextEvent sce) {
          //获取contextConfigLocation全局变量的值=spring-core.xml
          String contextConfigLocation = sce.getServletContext().getInitParameter("contextConfigLocation");
          //项目启动，初始化Spring容器
          ApplicationContext applicationContext = new ClassPathXmlApplicationContext(contextConfigLocation);
          sce.getServletContext().setAttribute("applicationContext", applicationContext);
      }
  
      @Override
      public void contextDestroyed(ServletContextEvent sce) {
          //项目销毁
      }
  }
  

  public class MyApplicationContextUtils {
  
  
      public static ApplicationContext getApplicationContext(ServletContext servletContext){
          return (ApplicationContext) servletContext.getAttribute("applicationContext");
      }
  
  }
  

  @WebServlet("/selectUserList")
  public class UserController extends HttpServlet {
  
  
      @Override
      protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
          //初始化Spring容器
          //ApplicationContext applicationContext = new ClassPathXmlApplicationContext("spring-core.xml");
          ApplicationContext applicationContext = MyApplicationContextUtils.getApplicationContext(getServletContext());
          UserService userService = applicationContext.getBean(UserService.class);
          try {
              //使用Spring容器中的UserService对象
              List<User> userList = userService.selectUserList();
              System.out.println("userList = " + userList);
          } catch (Exception e) {
              e.printStackTrace();
          }
      }
  
      @Override
      protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
          doGet(req, resp);
      }
  }
  

• 存在问题

  • 特别麻烦，不要自己写，Spring已经提供给你了！！

Spring整合Web环境终极版

• 概述

  • Spring框架提供了ContextLoaderListener、WebApplicationContextUtils

• 开发步骤

  • ①引入相关依赖
  • ②编写web.xml
    • 配置ContextLoaderListener
  • ③编写UserController
    • 使用WebApplicationContextUtils

• ①引入相关依赖

  <dependency>
      <groupId>org.springframeworkgroupId>
      <artifactId>spring-webartifactId>
      <version>${spring.version}version>
  dependency>
  
  <dependency>
      <groupId>org.springframeworkgroupId>
      <artifactId>spring-webmvcartifactId>
      <version>${spring.version}version>
  dependency>
  

• ②编写web.xml

  <context-param>
      <param-name>contextConfigLocationparam-name>
      <param-value>classpath:spring-core.xmlparam-value>
  context-param>
  
  <listener>
      <listener-class>org.springframework.web.context.ContextLoaderListenerlistener-class>
  listener>
  

• ③编写UserController

  @WebServlet("/selectUserList")
  public class UserController extends HttpServlet {
  
  
      @Override
      protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
          ApplicationContext applicationContext = WebApplicationContextUtils.getWebApplicationContext(getServletContext());
          UserService userService = applicationContext.getBean(UserService.class);
          try {
              //使用Spring容器中的UserService对象
              List<User> userList = userService.selectUserList();
              System.out.println("userList = " + userList);
          } catch (Exception e) {
              e.printStackTrace();
          }
      }
  
      @Override
      protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
          doGet(req, resp);
      }
  }
  

• 注意事项
  t.ContextLoaderListener
  

• ③编写UserController

  @WebServlet("/selectUserList")
  public class UserController extends HttpServlet {
  
  
      @Override
      protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
          ApplicationContext applicationContext = WebApplicationContextUtils.getWebApplicationContext(getServletContext());
          UserService userService = applicationContext.getBean(UserService.class);
          try {
              //使用Spring容器中的UserService对象
              List<User> userList = userService.selectUserList();
              System.out.println("userList = " + userList);
          } catch (Exception e) {
              e.printStackTrace();
          }
      }
  
      @Override
      protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
          doGet(req, resp);
      }
  }
  

• 注意事项

  • 在web项目中，引用第三方配置文件时，需要在前面加上"classpath"，比如:classpath:SqlMapConfig.xml"、“classpath:jdbc.properties”