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Spring MVC 文件上传与下载实现

1. 文件上传

1.1 创建 controller 类

package controller;import org.springframework.stereotype.Controller;import org.springframework.ui.Model;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.bind.annotation.RequestParam;import javax.servlet.ServletOutputStream;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import java.io.File;import java.io.FileInputStream;import java.io.IOException;import java.io.UnsupportedEncodingException;import java.util.ArrayList;import java.util.List;@Controllerpublic class FileDownController {    @RequestMapping("/showDownFiles")    public String showDownFiles(HttpServletRequest request, Model model) {        String realPath = request.getServletContext().getRealPath("/fileUpload/temp/");        File dir = new File(realPath);        File[] files = dir.listFiles();        ArrayList
   
     fileNameList = new ArrayList<>();        for (int i = 0; i < files.length; i++) {            fileNameList.add(files[i].getName());        }        model.addAttribute("files", fileNameList);        return "showDownFiles";    }    @RequestMapping("/down")    public String down(@RequestParam String filename, HttpServletRequest request, HttpServletResponse response) {        try {            String filePath = request.getServletContext().getRealPath("/fileUpload/temp/");            response.setHeader("Content-Type", "application/x-msdownload");            response.setHeader("Content-Disposition", "attachment; filename=" + toUTF8String(filename));            FileInputStream fis = new FileInputStream(filePath + "\\" + filename);            ServletOutputStream sos = response.getOutputStream();            byte[] b = new byte[1024];            int aRead = 0;            while ((aRead = fis.read(b)) != -1) {                sos.write(b, 0, aRead);            }            sos.flush();            fis.close();            sos.close();        } catch (IOException e) {            e.printStackTrace();        }        return null;    }    public String toUTF8String(String str) {        StringBuffer sb = new StringBuffer();        for (int i = 0; i < str.length(); i++) {            char c = str.charAt(i);            if (c >= 0 && c <= 255) {                sb.append(c);            } else {                try {                    byte[] b = Character.toString(c).getBytes("UTF-8");                    for (int j = 0; j < b.length; j++) {                        int k = b[j];                        if (k < 0) {                            k = 255;                        }                        sb.append("%" + Integer.toHexString(k).toUpperCase());                    }                } catch (UnsupportedEncodingException e) {                    e.printStackTrace();                    sb.append("%" + Integer.toHexString(c));                }            }        }        return sb.toString();    }}
   

1.2 创建 upload controller 类

package controller;import org.springframework.stereotype.Controller;import org.springframework.web.bind.annotation.ModelAttribute;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.multipart.MultipartFile;import pojo.UploadFile;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import java.io.File;import java.io.IOException;import java.util.List;@Controllerpublic class FileUploadController {    @RequestMapping("/upload")    public String upload(@ModelAttribute UploadFile uploadFile, HttpServletRequest request, HttpServletResponse response) {        String realPath = request.getServletContext().getRealPath("/fileUpload/temp/");        File targetDir = new File(realPath);        if (!targetDir.exists()) {            targetDir.mkdirs();        }        List
   
     files = uploadFile.getMyfile();        for (int i = 0; i < files.size(); i++) {            MultipartFile multipartFile = files.get(i);            String originalFilename = multipartFile.getOriginalFilename();            File targetFile = new File(realPath, originalFilename);            try {                multipartFile.transferTo(targetFile);            } catch (IOException e) {                e.printStackTrace();            }        }        return "success";    }}
   

1.3 创建 UploadFile 类

package pojo;import org.springframework.web.multipart.MultipartFile;import java.util.List;public class UploadFile {    private List
   
     myfile;    public List
    
      getMyfile() {        return myfile;    }    public void setMyfile(List
     
       myfile) {        this.myfile = myfile;    }}
     
    
   

2. 文件下载

2.1 设置正确的 MIME 类型

response.setHeader("Content-Type", "application/x-msdownload");

2.2 设置正确的 Content-Disposition 头

response.setHeader("Content-Disposition", "attachment; filename=" + toUTF8String(filename));

3. 项目配置

3.1 springmvc-servlet.xml

3.2 web.xml

       
            
     
      springmvc
             
     
      org.springframework.web.servlet.DispatcherServlet
             
     
      1
         
        
            
     
      springmvc
             
     
      /
         
        
            
     
      characterEncodingFilter
             
     
      org.springframework.web.filter.CharacterEncodingFilter
             
                 
      
       encoding
                  
      
       UTF-8
              
             
                 
      
       forceEncoding
                  
      
       true
              
         
        
            
     
      characterEncodingFilter
             
     
      /*
         
    
   

3.3 index.jsp

    
           
   
            选择文件1：
            选择文件2：
            选择文件3：
            选择文件4：
            选择文件5：
            
        
   

3.4 showDownFiles.jsp

        
   
        
                
     
${filename}
        
        
   

3.5 success.jsp

        
   
        
                
     
${file.originalFilename}
        
        
   

4. 注意事项

5. 运行测试

通过以上步骤，您应该能够顺利实现文件上传和下载功能。如果有任何问题，请仔细检查配置文件和代码，确保所有设置正确无误。

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