Spring MVC的文件上传和下载

谁践踏了优雅 2021-07-24 15:49 352阅读 0赞

**一 领域类**

package org.fkit.domain;
    
    import java.io.Serializable;
    
    import org.springframework.web.multipart.MultipartFile;
    
    
    // 域对象，实现序列化接口
    public class User implements Serializable{
    
        private static final long serialVersionUID = 1L;
    
        private String username;
        
        // 对应上传的file，类型为MultipartFile，上传文件会自动绑定到image属性当中
        private MultipartFile image;
    
        public User() {
            super();
            // TODO Auto-generated constructor stub
        }
    
        public String getUsername() {
            return username;
        }
    
        public void setUsername(String username) {
            this.username = username;
        }
    
        public MultipartFile getImage() {
            return image;
        }
    
        public void setImage(MultipartFile image) {
            this.image = image;
        }
    }

**二 控制器**

package org.fkit.controller;
    
    import java.io.File;
    import java.net.URLEncoder;
    
    import javax.servlet.http.HttpServletRequest;
    
    import org.apache.commons.io.FileUtils;
    import org.fkit.domain.User;
    import org.springframework.http.MediaType;
    import org.springframework.http.ResponseEntity;
    import org.springframework.http.ResponseEntity.BodyBuilder;
    import org.springframework.stereotype.Controller;
    import org.springframework.ui.Model;
    import org.springframework.web.bind.annotation.GetMapping;
    import org.springframework.web.bind.annotation.ModelAttribute;
    import org.springframework.web.bind.annotation.PostMapping;
    import org.springframework.web.bind.annotation.RequestHeader;
    import org.springframework.web.bind.annotation.RequestParam;
    import org.springframework.web.multipart.MultipartFile;
    
    @Controller
    public class FileUploadController{
        
        @GetMapping(value="/uploadForm")
         public String uploadForm(){
            // 跳转到文件上传页面
            return "uploadForm";
        }
        
        @GetMapping(value="/registerForm")
         public String registerForm(){
            // 跳转到文件上传页面
            return "registerForm";
        }
         
        
        // 上传文件会自动绑定到MultipartFile中
         @PostMapping(value="/upload")
         public String upload(HttpServletRequest request,
                @RequestParam("description") String description,
                @RequestParam("file") MultipartFile file) throws Exception{
             
            System.out.println(description);
            // 如果文件不为空，写入上传路径
            if(!file.isEmpty()){
                // 上传文件路径
                String path = request.getServletContext().getRealPath(
                        "/images");
                // 上传文件名
                String filename = file.getOriginalFilename();
                File filepath = new File(path,filename);
                // 判断路径是否存在，如果不存在就创建一个
                if (!filepath.getParentFile().exists()) {
                    filepath.getParentFile().mkdirs();
                }
                // 将上传文件保存到一个目标文件当中
                file.transferTo(new File(path+File.separator+ filename));
                System.out.println("上传文件路径：" + (path+File.separator+ filename));
                return "success";
            }else{
                return "error";
            }
             
         }
         
         @PostMapping(value="/register")
         public String register(HttpServletRequest request,
                 @ModelAttribute User user,
                 Model model)throws Exception{
             System.out.println(user.getUsername());
            // 如果文件不为空，写入上传路径
            if(!user.getImage().isEmpty()){
                // 上传文件路径
                String path = request.getServletContext().getRealPath(
                        "/images");
                // 上传文件名
                String filename = user.getImage().getOriginalFilename();
                File filepath = new File(path,filename);
                // 判断路径是否存在，如果不存在就创建一个
                if (!filepath.getParentFile().exists()) {
                    filepath.getParentFile().mkdirs();
                }
                // 将上传文件保存到一个目标文件当中
                user.getImage().transferTo(new File(path+File.separator+ filename));
                // 将用户添加到model
                model.addAttribute("filename", user.getImage().getOriginalFilename());
                System.out.println("上传文件路径：" + (path+File.separator+ filename));
                return "userInfo";
            }else{
                return "error";
            }
        }
         
         @GetMapping(value="/download")
         public ResponseEntity<byte[]> download(HttpServletRequest request,
                 @RequestParam("filename") String filename,
                 @RequestHeader("User-Agent") String userAgent
                 )throws Exception{
            // 下载文件路径
            String path = request.getServletContext().getRealPath(
                    "/images");
            // 构建File
            File file = new File(path+File.separator+ filename);
            // ok表示Http协议中的状态 200
            BodyBuilder builder = ResponseEntity.ok();
            // 内容长度
            builder.contentLength(file.length());
            // application/octet-stream ： 二进制流数据（最常见的文件下载）。
            builder.contentType(MediaType.APPLICATION_OCTET_STREAM);
            // 使用URLDecoder.decode对文件名进行解码
            filename = URLEncoder.encode(filename, "UTF-8");
            // 设置实际的响应文件名，告诉浏览器文件要用于【下载】、【保存】attachment 以附件形式
            // 不同的浏览器，处理方式不同，要根据浏览器版本进行区别判断
            if (userAgent.indexOf("MSIE") > 0) {
                    // 如果是IE，只需要用UTF-8字符集进行URL编码即可
                    builder.header("Content-Disposition", "attachment; filename=" + filename);
            } else {
                    // 而FireFox、Chrome等浏览器，则需要说明编码的字符集
                    // 注意filename后面有个*号，在UTF-8后面有两个单引号！
                    builder.header("Content-Disposition", "attachment; filename*=UTF-8''" + filename);
            }
            return builder.body(FileUtils.readFileToByteArray(file));
         }
    }

**三 配置文件**

<?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:c="http://www.springframework.org/schema/c"
        xmlns:mvc="http://www.springframework.org/schema/mvc"
         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/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">
            
        
        <context:component-scan base-package="org.fkit.controller"/>
        
        <mvc:annotation-driven/>
         
        <mvc:default-servlet-handler/>
            
        
         <bean id="viewResolver"
               class="org.springframework.web.servlet.view.InternalResourceViewResolver"
              p:prefix="/WEB-INF/content/" p:suffix=".jsp"/>
        
        
         <bean id="multipartResolver"  
             class="org.springframework.web.multipart.commons.CommonsMultipartResolver">  
               
            <property name="maxUploadSize">  
                <value>10485760</value>  
            </property>  
            
            <property name="defaultEncoding">
                <value>UTF-8</value>
            </property>
        </bean>
        
    </beans>

**四 视图**

1 error.jsp

2 success.jsp

3 registerForm.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
        pageEncoding="UTF-8"%>
    <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"  "http://www.w3.org/TR/html4/loose.dtd">
    <html>
    <head>
    <meta http-equiv="Content-Type" content="text/html;  charset=UTF-8">
    <title>用户注册</title>
    </head>
    <body>
         <h2>用户注册</h2>
         <form action="register" enctype="multipart/form-data"  method="post">
               <table>
                    <tr>
                         <td>用户名:</td>
                         <td><input type="text"  name="username"></td>
                    </tr>
                    <tr>
                         <td>请上传头像:</td>
                         <td><input type="file" name="image"></td>
                    </tr>
                    <tr>
                         <td><input type="submit" value="注册"></td>
                    </tr>
               </table>
         </form>
    </body>
    </html>

4 uploadForm.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
        pageEncoding="UTF-8"%>
    <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"  "http://www.w3.org/TR/html4/loose.dtd">
    <html>
    <head>
    <meta http-equiv="Content-Type" content="text/html;  charset=UTF-8">
    <title>文件上传</title>
    </head>
    <body>
         <h2>文件上传</h2>
         <form action="upload" enctype="multipart/form-data"  method="post">
               <table>
                    <tr>
                         <td>文件描述:</td>
                         <td><input type="text"  name="description"></td>
                    </tr>
                    <tr>
                         <td>请选择文件:</td>
                         <td><input type="file" name="file"></td>
                    </tr>
                    <tr>
                         <td><input type="submit" value="上传"></td>
                    </tr>
               </table>
         </form>
    </body>
    </html>

5 userinfo.jsp

**五 测试**

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NoZW5ncWl1bWluZw_size_16_color_FFFFFF_t_70][]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NoZW5ncWl1bWluZw_size_16_color_FFFFFF_t_70 1][]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NoZW5ncWl1bWluZw_size_16_color_FFFFFF_t_70 2][]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NoZW5ncWl1bWluZw_size_16_color_FFFFFF_t_70 3][]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NoZW5ncWl1bWluZw_size_16_color_FFFFFF_t_70 4][]

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NoZW5ncWl1bWluZw_size_16_color_FFFFFF_t_70]: /images/20210724/eeada81b19ae4449b4d756b8c3bb5f62.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NoZW5ncWl1bWluZw_size_16_color_FFFFFF_t_70 1]: /images/20210724/beafe5dc87984a76a9a969e850045cdf.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NoZW5ncWl1bWluZw_size_16_color_FFFFFF_t_70 2]: /images/20210724/cc00e61646d247fc93975b6aeb0f47b1.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NoZW5ncWl1bWluZw_size_16_color_FFFFFF_t_70 3]: /images/20210724/a1110dc0a3e94269aa932a9147236213.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NoZW5ncWl1bWluZw_size_16_color_FFFFFF_t_70 4]: /images/20210724/672bd9f898b94f1c9d02fe87717168dc.png