【编程不良人】快速入门SpringMVC学习笔记03---文件上传、文件下载、

1. 文件上传

配套视频：https://www.bilibili.com/video/BV1WD4y1D7kz?p=11

https://www.bilibili.com/video/BV1WD4y1D7kz?p=12

1.1 新建maven-webapp工程，添加java、resources目录

1.2 pom.xml引入依赖

  <!--spring核心及相关依赖-->
  <dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-core</artifactId>
    <version>4.3.2.RELEASE</version>
  </dependency>
  <dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-context</artifactId>
    <version>4.3.2.RELEASE</version>
  </dependency>
  <dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-context-support</artifactId>
    <version>4.3.2.RELEASE</version>
  </dependency>
  <dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-jdbc</artifactId>
    <version>4.3.2.RELEASE</version>
  </dependency>
  <dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-aop</artifactId>
    <version>4.3.2.RELEASE</version>
  </dependency>
  <dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-beans</artifactId>
    <version>4.3.2.RELEASE</version>
  </dependency>
  <dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-expression</artifactId>
    <version>4.3.2.RELEASE</version>
  </dependency>
  <dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-aspects</artifactId>
    <version>4.3.2.RELEASE</version>
  </dependency>
  <dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-tx</artifactId>
    <version>4.3.2.RELEASE</version>
  </dependency>
  <dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-web</artifactId>
    <version>4.3.2.RELEASE</version>
  </dependency>
  ​
  <!--springmvc核心依赖-->
  <dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-webmvc</artifactId>
    <version>4.3.2.RELEASE</version>
  </dependency>
  <!--servlet-api-->
  <dependency>
    <groupId>javax.servlet</groupId>
    <artifactId>servlet-api</artifactId>
    <version>2.5</version>
    <scope>provided</scope>
  </dependency>
  ​
  <!--jstl-->
  <dependency>
    <groupId>jstl</groupId>
    <artifactId>jstl</artifactId>
    <version>1.2</version>
  </dependency>
  ​
  <!--commons-fileupload-->
  <dependency>
    <groupId>commons-fileupload</groupId>
    <artifactId>commons-fileupload</artifactId>
    <version>1.4</version>
  </dependency>
  ​
  <!--fastjson-->
  <dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>fastjson</artifactId>
    <version>1.2.62</version>
  </dependency>
  ​
  <!--@ResponseBody注解在转换json时使用jackson依赖-->
  <dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-databind</artifactId>
    <version>2.9.0</version>
  </dependency>

1.3 配置web.xml

  <!DOCTYPE web-app PUBLIC
   "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
   "http://java.sun.com/dtd/web-app_2_3.dtd" >
  ​
  <web-app>
    <display-name>Archetype Created Web Application</display-name>
  ​
    <!--配置post请求方式中文乱码的Filter-->
    <filter>
      <filter-name>charset</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>charset</filter-name>
      <url-pattern>/*</url-pattern>
    </filter-mapping>
  ​
    <!--配置springmvc核心servlet-->
    <servlet>
      <servlet-name>springmvc</servlet-name>
      <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
      <!--配置springmvc配置文件位置-->
      <init-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>classpath:springmvc.xml</param-value>
      </init-param>
    </servlet>
    <servlet-mapping>
      <servlet-name>springmvc</servlet-name>
      <url-pattern>/</url-pattern>
    </servlet-mapping>
  </web-app>
  ​

1.4 引入springmvc.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: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/context http://www.springframework.org/schema/context/spring-context.xsd http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc.xsd">
      <!--开启注解扫描-->
      <context:component-scan base-package="com.study.controller"/>
  ​
      <!--开启注解驱动-->
      <mvc:annotation-driven/>
  ​
      <!--配置视图解析器-->
      <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
          <property name="prefix" value="/"/>
          <property name="suffix" value=".jsp"/>
      </bean>
  ​
      <!--配置静态资源拦截-->
      <mvc:default-servlet-handler/>
  ​
      <!--配置文件上传解析器：id必须指定为multipartResolver-->
      <bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
          <!--控制文件上传大小，单位：字节，默认没有大小限制，这里设置为2M-->
          <property name="maxUploadSize" value="2097152"/>
      </bean>
  ​
  </beans>

1.5 开发上传页面upload.jsp

  
  <%@page contentType="text/html; UTF-8" pageEncoding="UTF-8" isELIgnored="false" %>
  <!doctype html>
  <html lang="en">
  <head>
      <meta charset="UTF-8">
      <meta name="viewport"
            content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0">
      <meta http-equiv="X-UA-Compatible" content="ie=edge">
      <title>测试文件上传</title>
  </head>
  <body>
      <h1>文件上传</h1>
      <form action="${pageContext.request.contextPath}/file/upload" method="post" enctype="multipart/form-data">
          <input type="file" name="img"/>
          <input type="submit" value="上传文件">
      </form>
  </body>
  </html>

1.6 开发控制器FileController

  package com.study.controller;
  ​
  import org.apache.commons.io.FilenameUtils;
  import org.springframework.stereotype.Controller;
  import org.springframework.web.bind.annotation.RequestMapping;
  import org.springframework.web.multipart.MultipartFile;
  ​
  import javax.servlet.http.HttpServletRequest;
  import java.io.File;
  import java.io.IOException;
  import java.time.LocalDate;
  import java.util.UUID;
  ​
  /**
   * @ClassName FileController
   * @Description TODO
   * @Author Jiangnan Cui
   * @Date 2022/4/24 9:24
   * @Version 1.0
   */
  @Controller
  @RequestMapping("file")
  public class FileController {
  ​
      /**
       * @MethodName upload
       * @Description 测试文件上传
       * @param: img
       * @return: java.lang.String
       * @Author Jiangnan Cui
       * @Date 2022/4/24 9:34
       */
      @RequestMapping("upload")
      public String upload(MultipartFile img, HttpServletRequest request) throws IOException {
          //获取上传文件属性
          System.out.println("文件原始名称为：" + img.getOriginalFilename());
          System.out.println("文件大小：" + img.getSize());
          System.out.println("文件类型：" + img.getContentType());
  ​
          //1.根据upload相对路径获取部署到服务之后的绝对路径
          //获取上传路径
          String realPath = request.getSession().getServletContext().getRealPath("/upload");
          System.out.println("上传路径为：" + realPath);
  ​
          //2.修改文件原始名称
          //获取原始文件名称
          String originalFileName = img.getOriginalFilename();
          //获取原始文件后缀 FilenameUtils为工具类，里面提供了一些静态方法
          String extension = FilenameUtils.getExtension(originalFileName);
          //设置新文件名
          String newFileName = UUID.randomUUID().toString().replace("-","") + "." + extension;
          System.out.println("文件新名称为: " + newFileName);
  ​
          //3.生成当天日期目录
          LocalDate now = LocalDate.now();
          //realPath：父路径，now.toString()：子路径
          File dateDir = new File(realPath, now.toString());
          if(!dateDir.exists())
              dateDir.mkdirs();
          System.out.println("日期目录为：" + dateDir.getName());
  ​
          //4.上传文件到服务器中对应日期的目录中
          //dateDir：存放文件的日期目录，newFileName：新文件名
          img.transferTo(new File(dateDir,newFileName));
          return "index";
      }
  }
  ​

1.7 部署到tomcat服务器上进行测试

访问路径：http://localhost:8888/springmvc02/upload.jsp，选择文件后进行上传

上传成功后跳转到index.jsp页面：

控制台输出文件信息、target目录下出现upload本地上传的文件：

1.8 总结

springmvc中文件上传流程：

springmvc中文件上传细节处理：

2. 文件下载

（待完善）