javaweb implementation file download method and instance code

javaweb implementation file download

Stop using it < a > The tag is downloaded, and this will open the file instead of downloading it

Such as:

< a href="E:\MyDesktop\37fecd65330184de67d419a8d02e7081.jpg" > download < /a >

If I write this way, the browser will open the image directly, unless it's a file that a browser can't open

So we still need to use java itself for file reading and writing to download files

< a href="downloadFile?filename= < s:property value='document_filename'/ > " > download < /a >

package com.cpsec.tang.chemical.action;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.List;
import java.util.Random;

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

import org.apache.struts2.ServletActionContext;
import org.springframework.stereotype.Controller;
import com.cpsec.tang.chemical.biz.DocumentBiz;
import com.cpsec.tang.chemical.entity.Document;
import com.cpsec.tang.chemical.util.Pager;
import com.opensymphony.xwork2.ActionSupport;

@Controller("documentAction")
public class DocumentAction extends ActionSupport{private String filename;
  public String downloadFile(){
    System.out.println(filename);
    try {
      HttpServletResponse response=ServletActionContext.getResponse();
      // Settings file MIME type  
      response.setContentType(ServletActionContext.getServletContext().getMimeType(filename)); 
      // Set up the Content-Disposition 
      response.setHeader("Content-Disposition", "attachment;filename="+filename); 
      // Gets the absolute path to the target file  
      String fullFileName = ServletActionContext.getServletContext().getRealPath("/files/" + filename); 
      //System.out.println(fullFileName); 
      // Read the file  
      InputStream in = new FileInputStream(fullFileName); 
      // Read the target file through response Write the target file to the client 
      OutputStream out = response.getOutputStream(); 
      // Write files  
      int b; 
      while((b=in.read())!= -1) 
      { 
        out.write(b); 
      } 
      in.close(); 
      out.close(); 
    } catch (Exception e) {
      e.printStackTrace();
    }
    return SUCCESS;
  }
  
}

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