javaweb 实现文件下载的方法及实例代码

时间:2022-09-05 13:46:16

javaweb 实现文件下载

不要再说用<a>标签下载了,这个会把文件打开而不是下载

例如:

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

如果我这样写,浏览器就会把图片直接打开,除非是一个浏览器打不开的文件

所以我们还是要用到java本身的文件读写来进行文件的下载

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

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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();
      //设置文件MIME类型
      response.setContentType(ServletActionContext.getServletContext().getMimeType(filename));
      //设置Content-Disposition
      response.setHeader("Content-Disposition", "attachment;filename="+filename);
      //获取目标文件的绝对路径
      String fullFileName = ServletActionContext.getServletContext().getRealPath("/files/" + filename);
      //System.out.println(fullFileName);
      //读取文件
      InputStream in = new FileInputStream(fullFileName);
      //读取目标文件,通过response将目标文件写到客户端
      OutputStream out = response.getOutputStream();
      //写文件
      int b;
      while((b=in.read())!= -1)
      {
        out.write(b);
      }
      in.close();
      out.close();
    } catch (Exception e) {
      e.printStackTrace();
    }
    return SUCCESS;
  }
  
}

感谢阅读,希望能帮助到大家,谢谢大家对本站的支持!

原文链接:http://www.cnblogs.com/bunuo/p/download.html