Spring MVC ：从入门到精通(下)

一、前言

本文主要讲解 SpringMVC 的核心进阶内容，包括拦截器、文件上传、全局异常处理器，以及 SSM（Spring+SpringMVC+MyBatis）的完整整合流程，通过实战案例帮助大家掌握这些核心知识点的使用方式。

二、拦截器（Interceptor）

2.1 什么是拦截器

Spring MVC 中的拦截器（Interceptor）类似于 Servlet 中的过滤器（Filter），主要用于拦截用户请求并作相应处理（如权限验证、登录状态判断等）。拦截器依赖于 web 框架，基于 Java 反射机制实现，属于面向切面编程（AOP）的应用。

2.2 自定义基础拦截器

2.2.1 创建拦截器类

实现HandlerInterceptor接口，重写核心方法：

java

package com.hg.interceptor;

import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class CustomHandlerInterceptor implements HandlerInterceptor {
    /**
     * 控制器方法调用前执行，返回true继续执行，false中断后续操作
     */
    @Override
    public boolean preHandle(HttpServletRequest request,
                      HttpServletResponse response, Object object) throws Exception {
        System.out.println("HandlerInterceptor preHandle ....");
        return true;
    }

    /**
     * 控制器方法调用后、解析视图前执行，可修改视图/模型数据
     */
    @Override
    public void postHandle(HttpServletRequest request,HttpServletResponse response, 
                         Object object, ModelAndView modelAndView) throws Exception {
        System.out.println("HandlerInterceptor postHandle ....");
    }

    /**
     * 整个请求完成（视图渲染结束）后执行，用于资源清理、日志记录
     */
    @Override
    public void afterCompletion(HttpServletRequest request,
        HttpServletResponse response,Object object, Exception e) throws Exception {
        System.out.println("HandlerInterceptor afterCompletion ....");
    }
}

2.2.2 配置拦截器

在 SpringMVC 配置文件中注册拦截器：

xml

<!--配置拦截器 -->
<mvc:interceptors>
    <mvc:interceptor>
        <!-- 匹配所有URL路径 -->
        <mvc:mapping path="/**"></mvc:mapping>
        <bean class="com.hg.interceptor.CustomHandlerInterceptor"></bean>
    </mvc:interceptor>
</mvc:interceptors>

2.2.3 测试拦截器

编写 Controller：

java

@Controller
@RequestMapping("/account")
public class AccountController {
    @RequestMapping("/findAccount12")
    public String findAccount12(Model model) {
        model.addAttribute("msg", "欢迎你 springmvc");
        System.out.println("controller的方法执行了......");
        return "success";
    }
}

页面添加测试链接：

html

<a href="/account/findAccount12">拦截器</a>

2.3 登录状态拦截器（实战场景）

2.3.1 创建登录拦截器

java

package com.hg.interceptor;

import org.springframework.web.servlet.HandlerInterceptor;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class LoginInterceptor implements HandlerInterceptor {
    @Override
    public boolean preHandle(HttpServletRequest request,
           HttpServletResponse response, Object object) throws Exception {
        // 获取会话中的用户信息
        String user = (String) request.getSession().getAttribute("user_session");
        if (user != null) {// 已登录，放行
            System.out.println("获得用户信息："+user);
            return true;
        } else {// 未登录，跳转登录页
            response.sendRedirect(request.getContextPath() +"/login.jsp");
            return false;
        }
    }
}

2.3.2 配置登录拦截器

xml

<mvc:interceptors>
    <mvc:interceptor>
        <mvc:mapping path="/**"></mvc:mapping>
        <bean class="com.hg.interceptor.LoginInterceptor"></bean>
    </mvc:interceptor>
</mvc:interceptors>

2.3.3 测试登录拦截

Controller 方法：

java

@RequestMapping("/findAccount13")
public String findAccount13(Model model) {
    model.addAttribute("msg", "欢迎你 springmvc");
    System.out.println("controller的方法执行了......");
    return "success";
}

页面测试（模拟登录 / 未登录）：

html

<%
   // 模拟已登录（注释此行则模拟未登录）
   session.setAttribute("user_session","User{name:张二狗,age:18}");
%>
<a href="/account/findAccount13">登录拦截器</a>

三、文件上传

3.1 添加依赖

xml

<!--文件上传依赖-->
<dependency>
    <groupId>commons-fileupload</groupId>
    <artifactId>commons-fileupload</artifactId>
    <version>1.3.1</version>
</dependency>

3.2 配置文件上传解析器

注意：id 必须为 multipartResolver

xml

<bean id="multipartResolver" 
      class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
    <!-- 最大上传大小：5MB -->
    <property name="maxUploadSize" value="5242880" />
    <!-- 编码格式 -->
    <property name="defaultEncoding" value="UTF-8" />
</bean>

3.3 静态资源映射（可选）

xml

​
<!-- 映射静态资源：URL匹配/upload/**，对应本地/upload/目录 -->
<mvc:resources mapping="/upload/*" location="/upload/" />

​

3.4 实现文件上传功能

3.4.1 编写上传 Controller

java

​@Controller
@RequestMapping("/account")
public class AccountController {

  @RequestMapping("/uploads")
  public String upload(HttpServletRequest request, MultipartFile head, Model model) throws IOException {
        System.out.println("springmvc方式的文件上传");
        //获取要上传的文件目录
        String path =
                request.getSession().getServletContext().getRealPath("/upload");
        System.out.println("path:"+path);
        //根据文件上传的目录创建File对象，如果不存在则创建1个File对象
        File file = new File(path);
        if(!file.exists()){
            //创建一个file对象
            file.mkdirs();
        }
        //获取文件上传名称
        String filename = head.getOriginalFilename();
        //完成文件上传
        head.transferTo(new File(path,filename));

        model.addAttribute("msg", filename);
        return "success";
    }
}

​

​

3.4.2 页面上传表单

index.jsp

​
<%-- 必须指定enctype为multipart/form-data --%>
<form action="/account/uploads" method="post" enctype="multipart/form-data">
    文件: <input type="file" name="head">
    <input type="submit" value="上传">
</form>
​

success.jsp (上传成功,跳转页面)

    <h2>${msg},你好</h2>
    <img src="/upload/${msg}">   <!-- 显示上传的图片等 -->

四、全局异常处理器

4.1 异常处理思路

系统中 DAO、Service、Controller 层的异常统一向上抛出，最终由 SpringMVC 前端控制器交给异常处理器处理，避免错误信息直接暴露在浏览器。

4.2 创建全局异常处理器

java

运行

@Component
public class CustomExceptionResolver implements HandlerExceptionResolver {
    @Override
    public ModelAndView resolveException(HttpServletRequest request,
                    HttpServletResponse response, Object handler, Exception ex) {
        ModelAndView modelAndView = new ModelAndView();
        // 封装异常信息
        modelAndView.addObject("message", ex.toString());
        // 跳转错误页面
        modelAndView.setViewName("error");
        return modelAndView;
    }
}

4.3 测试异常处理

Controller 模拟异常：

java

运行

@RequestMapping("/findAccount14")
public String findAccount14(Model model) {
    model.addAttribute("msg", "欢迎你 springmvc");
    // 模拟算术异常
    int i = 10/0;
    return "success";
}

页面测试链接：

html

预览

<a href="/account/findAccount14">异常处理器</a>

五、SSM 整合实战

5.1 环境准备

5.1.1 建库建表

sql

CREATE TABLE `account` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `name` varchar(20) DEFAULT NULL,
  `money` double DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

5.1.2 依赖配置（pom.xml）

xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.hg</groupId>
    <artifactId>ssm</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>war</packaging>

    <properties>
        <spring.version>5.2.8.RELEASE</spring.version>
        <slf4j.version>1.6.6</slf4j.version>
        <log4j.version>1.2.12</log4j.version>
        <mysql.version>8.0.29</mysql.version>
        <mybatis.version>3.4.5</mybatis.version>
        <druid.version>1.1.0</druid.version>
    </properties>
    <dependencies>
        <!-- Spring核心依赖 -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-aspects</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-tx</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-jdbc</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <!-- MyBatis -->
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>${mybatis.version}</version>
        </dependency>
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis-spring</artifactId>
            <version>1.3.0</version>
        </dependency>
        <!-- MySQL驱动 -->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>${mysql.version}</version>
        </dependency>
        <!-- 德鲁伊连接池 -->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>${druid.version}</version>
        </dependency>
        <!-- JSP/JSTL -->
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>servlet-api</artifactId>
            <version>2.5</version>
            <scope>provided</scope>
        </dependency>
        <dependency>
            <groupId>javax.servlet.jsp</groupId>
            <artifactId>jsp-api</artifactId>
            <version>2.0</version>
            <scope>provided</scope>
        </dependency>
        <dependency>
            <groupId>jstl</groupId>
            <artifactId>jstl</artifactId>
            <version>1.2</version>
        </dependency>
        <!-- 日志 -->
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-log4j12</artifactId>
            <version>${slf4j.version}</version>
        </dependency>        
    </dependencies>
    <build>
        <plugins>
            <!-- Tomcat插件 -->
            <plugin>
                <groupId>org.apache.tomcat.maven</groupId>
                <artifactId>tomcat7-maven-plugin</artifactId>
                <version>2.2</version>
                <configuration>
                    <port>8080</port>
                    <path>/</path>
                </configuration>
            </plugin>
        </plugins>
        <!-- 资源扫描 -->
        <resources>
            <resource>
                <directory>src/main/java</directory>
                <includes>
                    <include>**/*.xml</include>
                </includes>
            </resource>
            <resource>
                <directory>src/main/resources</directory>
            </resource>
        </resources>
    </build>
</project>

5.1.3 日志配置（log4j.properties）

properties

log4j.rootLogger=DEBUG,A1

log4j.appender.A1=org.apache.log4j.ConsoleAppender
log4j.appender.A1.layout=org.apache.log4j.PatternLayout
log4j.appender.A1.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss} - %c%l%m%n

5.1.4 数据库配置（db.properties）

properties

jdbc.driver=com.mysql.cj.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/ssm?useSSL=false&serverTimezone=Asia/Shanghai&characterEncoding=UTF-8
jdbc.username=root
jdbc.password=1111

5.2 核心配置文件

5.2.1 DAO 层配置（applicationContext-dao.xml）

xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:tx="http://www.springframework.org/schema/tx"
       xmlns:aop="http://www.springframework.org/schema/aop"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
       http://www.springframework.org/schema/beans/spring-beans.xsd
       http://www.springframework.org/schema/context
       http://www.springframework.org/schema/context/spring-context.xsd
       http://www.springframework.org/schema/tx
       http://www.springframework.org/schema/tx/spring-tx.xsd
       http://www.springframework.org/schema/aop
       https://www.springframework.org/schema/aop/spring-aop.xsd">
    <!-- 加载数据库配置文件 -->
    <context:property-placeholder location="classpath:db.properties" />
    <!-- 德鲁伊连接池 -->
    <bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource"
          destroy-method="close">
        <property name="url" value="${jdbc.url}" />
        <property name="username" value="${jdbc.username}" />
        <property name="password" value="${jdbc.password}" />
        <property name="driverClassName" value="${jdbc.driver}" />
        <property name="maxActive" value="10" />
        <property name="minIdle" value="5" />
    </bean>
    <!-- SqlSessionFactory配置 -->
    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <property name="dataSource" ref="dataSource" />
        <!-- 实体类别名包 -->
        <property name="typeAliasesPackage" value="com.hg.pojo"></property>
    </bean>
    <!-- Mapper扫描器 -->
    <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
        <property name="basePackage" value="com.hg.mapper"></property>
        <property name="sqlSessionFactoryBeanName" value="sqlSessionFactory"></property>
    </bean>
</beans>

5.2.2 事务配置（applicationContext-tx.xml）

xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:tx="http://www.springframework.org/schema/tx"
       xmlns:aop="http://www.springframework.org/schema/aop"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
       http://www.springframework.org/schema/beans/spring-beans.xsd
       http://www.springframework.org/schema/context
       http://www.springframework.org/schema/context/spring-context.xsd
       http://www.springframework.org/schema/tx
       http://www.springframework.org/schema/tx/spring-tx.xsd
       http://www.springframework.org/schema/aop
       https://www.springframework.org/schema/aop/spring-aop.xsd">
    <!-- 事务管理器 -->
    <bean id="transactionManager"
          class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
        <property name="dataSource" ref="dataSource"/>
    </bean>
    <!-- 事务通知 -->
    <tx:advice id="txAdvice" transaction-manager="transactionManager">
        <tx:attributes>
            <tx:method name="insert*" propagation="REQUIRED"/>
            <tx:method name="delete*" propagation="REQUIRED"/>
            <tx:method name="update*" propagation="REQUIRED"/>
            <tx:method name="select*" propagation="SUPPORTS" read-only="true"/>
            <tx:method name="get*" propagation="SUPPORTS" read-only="true"/>
        </tx:attributes>
    </tx:advice>
    <!-- 事务切面 -->
    <aop:config>
        <aop:advisor advice-ref="txAdvice"
                     pointcut="execution(* com.hg.service.*.*(..))" />
    </aop:config>
</beans>

5.2.3 Service 层配置（applicationContext-service.xml）

xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:tx="http://www.springframework.org/schema/tx"
       xmlns:aop="http://www.springframework.org/schema/aop"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
       http://www.springframework.org/schema/beans/spring-beans.xsd
       http://www.springframework.org/schema/context
       http://www.springframework.org/schema/context/spring-context.xsd
       http://www.springframework.org/schema/tx
       http://www.springframework.org/schema/tx/spring-tx.xsd
       http://www.springframework.org/schema/aop
       https://www.springframework.org/schema/aop/spring-aop.xsd">
    <!-- 扫描Service包 -->
    <context:component-scan base-package="com.hg.service"></context:component-scan>
</beans>

5.2.4 SpringMVC 配置（springmvc.xml）

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:context="http://www.springframework.org/schema/context"
       xmlns:mvc="http://www.springframework.org/schema/mvc"
       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">
    <!-- 扫描Controller包 -->
    <context:component-scan base-package="com.hg.controller"></context:component-scan>
    <!-- 视图解析器 -->
    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="prefix" value="/WEB-INF/pages/"></property>
        <property name="suffix" value=".jsp"></property>
    </bean>
</beans>

5.2.5 Web 配置（web.xml）

xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
         version="4.0">
    <!-- Spring容器监听器 -->
    <context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>classpath:applicationContext-*.xml</param-value>
    </context-param>
    <listener>
        <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
    </listener>

    <!-- 解决POST乱码过滤器 -->
    <filter>
        <filter-name>CharacterEncodingFilter</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>CharacterEncodingFilter</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>

    <!-- SpringMVC前端控制器 -->
    <servlet>
        <servlet-name>springmvc</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>classpath:springmvc.xml</param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>
    <servlet-mapping>
        <servlet-name>springmvc</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>
</web-app>

5.3 业务代码编写

5.3.1 实体类（Account.java）

java

运行

public class Account {
    private Integer id;
    private String name;
    private Double money;
    
    // Getter/Setter/toString
    public Integer getId() {
        return id;
    }
    public void setId(Integer id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public Double getMoney() {
        return money;
    }
    public void setMoney(Double money) {
        this.money = money;
    }
    @Override
    public String toString() {
        return "Account{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", money=" + money +
                '}';
    }
}

5.3.2 Mapper 层

接口（AccountMapper.java）：

java

运行

public interface AccountMapper {
    List<Account> selectAccount();
}

映射文件（AccountMapper.xml）：

xml

<?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="com.hg.mapper.AccountMapper">
    <select id="selectAccount" resultType="Account">
		select * from account
	</select>
</mapper>

5.3.3 Service 层

java

运行

@Service
public class AccountServiceImpl implements AccountService {
    @Autowired
    private AccountMapper accountMapper;
    @Override
    public List<Account> selectAccount() {
        return accountMapper.selectAccount();
    }
}

5.3.4 Controller 层

java

运行

@Controller
@RequestMapping("/account")
public class AccountController {
    @Autowired
    private AccountService accountService;

    @RequestMapping("/selectAccount")
    public String selectAccount(Model model){
        List<Account> list = accountService.selectAccount();
        model.addAttribute("list",list);
        return "select_account";
    }
}

5.3.5 页面展示（select_account.jsp）

html

预览

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<html>
<head>
    <title>账户列表</title>
</head>
<body>
<h2>查询所有账户</h2>
<table width="30%" border="1" cellspacing="0" cellpadding="0">
    <tr>
        <th>id</th>
        <th>name</th>
        <th>money</th>
    </tr>
    <c:forEach var="item" items="${list}">
        <tr>
            <td>${item.id}</td>
            <td>${item.name}</td>
            <td>${item.money}</td>
        </tr>
    </c:forEach>
</table>
</body>
</html>

5.4 测试 SSM 整合

启动 Tomcat，访问http://localhost:8080/account/selectAccount，即可查询数据库中的账户列表。

5.5 拓展作业

1. 基于现有框架完成用户登录功能
2. 完成用户注册功能
3. 整合图片上传到用户注册 / 编辑功能中
4. 为所有业务添加全局异常处理
5. 完善登录状态校验拦截器（排除登录 / 注册页面）
6. 为 Account 表添加开户日期字段，并实现新增 / 查询功能

六、总结

本文详细讲解了 SpringMVC 拦截器、文件上传、全局异常处理器的使用，以及 SSM 整合的完整流程。这些知识点是 SpringMVC 开发中的核心内容，掌握后能够应对大部分企业级 Web 开发场景。建议大家结合实战案例反复练习，加深对知识点的理解和运用。