【SpringMVC 进阶】拦截器、文件上传、异常处理与 SSM 整合全解析

前言

SpringMVC 作为主流的 Web 开发框架，在企业级应用中占据重要地位。本文将从实际开发场景出发，详细讲解 SpringMVC 核心进阶知识点：拦截器（登录校验）、文件上传、全局异常处理器，以及 SSM（Spring+SpringMVC+MyBatis）整合全过程，附带完整代码示例，助力快速上手实战。

一、拦截器（Interceptor）

1.1 什么是拦截器？

Spring MVC 中的拦截器类似于 Servlet 中的过滤器（Filter），主要用于拦截用户请求并做自定义处理（如权限验证、登录状态校验、日志记录等）。它依赖 Web 框架，基于 Java 反射机制实现，属于 AOP 编程思想的典型应用。

1.2 自定义基础拦截器

步骤 1：创建拦截器类

实现 HandlerInterceptor 接口，重写核心方法：

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（核心）
     * @return true：继续执行（下一个拦截器/处理器）；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、视图解析前执行
     * 可修改视图/模型数据（如添加全局公共数据）
     */
    @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、日志记录等
     */
    @Override
    public void afterCompletion(HttpServletRequest request,
        HttpServletResponse response,Object object, Exception e) throws Exception {
        System.out.println("HandlerInterceptor afterCompletion ....");
    }
}

步骤 2：配置拦截器（springmvc.xml）

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

步骤 3：测试

编写 Controller：

@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";
    }
}

JSP 超链接：

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

访问链接后，控制台会依次输出 preHandle → 控制器方法 → postHandle → afterCompletion。

二、文件上传

2.1 添加依赖（pom.xml）

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

2.2 配置文件上传解析器（springmvc.xml）

注意：id 必须为 multipartResolver

<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>

<!-- 静态资源映射（可选，用于访问上传后的文件） -->
<mvc:resources mapping="/head/**" location="/head/"/>

2.3 编写上传接口

@Controller
@RequestMapping("/account")
public class AccountController {
    @RequestMapping(path="/upload")
    public String upload(HttpServletRequest request, 
                         MultipartFile head, Model model) throws IOException {
        System.out.println("springmvc方式的文件上传");
        // 1. 获取上传目录（项目部署路径下的uploads文件夹）
        String path = request.getSession().getServletContext().getRealPath("/uploads");
        // 2. 创建目录（不存在则创建）
        File fileDir = new File(path);
        if(!fileDir.exists()) fileDir.mkdirs();
        // 3. 获取文件名并上传
        String filename = head.getOriginalFilename();
        head.transferTo(new File(fileDir, filename));
        
        model.addAttribute("msg", "文件上传成功！");
        return "success";
    }
}

2.4 前端上传表单

<form action="/account/upload" method="post" enctype="multipart/form-data">
    文件: <input type="file" name="head"/>
    <input type="submit" value="提交"/>
</form>

关键：表单必须设置 enctype="multipart/form-data"，否则无法上传二进制文件。

三、全局异常处理器

3.1 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 前端控制器交给自定义异常处理器处理，避免直接暴露错误信息到页面，提升用户体验。

3.2 自定义异常处理器

import org.springframework.stereotype.Component;
import org.springframework.web.servlet.HandlerExceptionResolver;
import org.springframework.web.servlet.ModelAndView;

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

@Component // 交给Spring容器管理
public class CustomExceptionResolver implements HandlerExceptionResolver {
    @Override
    public ModelAndView resolveException(HttpServletRequest request,
                                         HttpServletResponse response, 
                                         Object handler, Exception ex) {
        // 1. 创建ModelAndView对象
        ModelAndView mv = new ModelAndView();
        // 2. 封装异常信息
        mv.addObject("message", "系统异常：" + ex.toString());
        // 3. 设置错误页面
        mv.setViewName("error");
        return mv;
    }
}

3.3 测试

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

JSP 超链接：

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

四、SSM 整合（Spring+SpringMVC+MyBatis）

4.1 环境准备

1. 建库建表

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;

2. 核心依赖（pom.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 -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</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 + 整合包 -->
        <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>
        
        <!-- 数据库 -->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>${mysql.version}</version>
        </dependency>
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>${druid.version}</version>
        </dependency>
        
        <!-- Web相关 -->
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>servlet-api</artifactId>
            <version>2.5</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>
        <!-- Tomcat插件 -->
        <plugins>
            <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（MyBatis映射文件） -->
        <resources>
            <resource>
                <directory>src/main/java</directory>
                <includes>
                    <include>**/*.xml</include>
                </includes>
            </resource>
            <resource>
                <directory>src/main/resources</directory>
            </resource>
        </resources>
    </build>
</project>

4.2 核心配置文件

1. 数据库配置（db.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

2. Spring DAO 层配置（applicationContext-dao.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"
       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">
    <!-- 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"/>
        <!-- 实体类别名扫描 -->
        <property name="typeAliasesPackage" value="com.hg.pojo"/>
    </bean>
    
    <!-- Mapper接口扫描 -->
    <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
        <property name="basePackage" value="com.hg.mapper"/>
        <property name="sqlSessionFactoryBeanName" value="sqlSessionFactory"/>
    </bean>
</beans>

3. 事务配置（applicationContext-tx.xml）

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:tx="http://www.springframework.org/schema/tx"
       xmlns:aop="http://www.springframework.org/schema/aop"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       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/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:attributes>
    </tx:advice>
    
    <!-- 切面配置 -->
    <aop:config>
        <aop:advisor advice-ref="txAdvice"
                     pointcut="execution(* com.hg.service.*.*(..))"/>
    </aop:config>
</beans>

4. Service 层配置（applicationContext-service.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"
       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">
    <!-- 扫描Service包 -->
    <context:component-scan base-package="com.hg.service"/>
</beans>

5. SpringMVC 配置（springmvc.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:mvc="http://www.springframework.org/schema/mvc"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       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 -->
    <context:component-scan base-package="com.hg.controller"/>
    
    <!-- 视图解析器 -->
    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="prefix" value="/WEB-INF/pages/"/>
        <property name="suffix" value=".jsp"/>
    </bean>
    
    <!-- 开启MVC注解驱动 -->
    <mvc:annotation-driven/>
</beans>

6. Web 配置（web.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容器加载 -->
    <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 -->
    <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>

4.3 业务代码编写

1. 实体类（Account.java）

package com.hg.pojo;

public class Account {
    private Integer id;
    private String name;
    private Double money;

    // getter/setter/toString 省略
}

2. Mapper 接口 + 映射文件

AccountMapper.java：

package com.hg.mapper;

import com.hg.pojo.Account;
import java.util.List;

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

AccountMapper.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>

3. Service 层

AccountService.java：

package com.hg.service;

import com.hg.pojo.Account;
import java.util.List;

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

AccountServiceImpl.java：

package com.hg.service.impl;

import com.hg.mapper.AccountMapper;
import com.hg.pojo.Account;
import com.hg.service.AccountService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.List;

@Service
public class AccountServiceImpl implements AccountService {
    @Autowired
    private AccountMapper accountMapper;

    @Override
    public List<Account> selectAccount() {
        return accountMapper.selectAccount();
    }
}

4. Controller 层

package com.hg.controller;

import com.hg.pojo.Account;
import com.hg.service.AccountService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;

import java.util.List;

@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. 前端页面（select_account.jsp）

<%@ 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="account" items="${list}">
        <tr>
            <td>${account.id}</td>
            <td>${account.name}</td>
            <td>${account.money}</td>
        </tr>
    </c:forEach>
</table>
</body>
</html>

4.4 测试

启动 Tomcat，访问 http://localhost:8080/account/selectAccount，即可看到数据库中的账户列表。

五、拓展作业（实战强化）

1. 基于登录拦截器实现完整的 "登录 - 注册" 流程；
2. 结合文件上传功能，实现用户头像上传并关联到账户信息；
3. 为 SSM 整合项目添加全局异常处理，捕获数据库 / 业务异常；
4. 优化登录拦截器，排除登录 / 注册接口（避免死循环）；
5. 为 Account 表添加create_time（开户日期）字段，实现日期的新增 / 查询。

总结

本文从 SpringMVC 核心进阶特性入手，逐步讲解了拦截器、文件上传、异常处理器的实现逻辑，并完整梳理了 SSM 整合的全流程。这些知识点是企业级 Web 开发的核心，掌握后可快速搭建规范的 Java Web 项目。建议结合作业动手实践，加深对知识点的理解与运用。