java和Struts2实现文件下载和上传详解编程语言

本程序是通过java和struts2先实现把文件上传到服务器或者是存储到硬盘，然后把该文件下载下来：

一：首先是struts2配置文件：result返回类型一定要写成type=”stream”

<package name=”download” extends=”struts-default”>

   <action name=”download_*” class=”upload.action.FileDownload” method=”{1}”>

       <result name=”success” type=”stream”>

           <param name=”contentType”>text/plain</param>

           <param name=”contentDisposition”>attachment;fileName=”${fileName}”</param>

           <param name=”inputName”>downloadFile</param>

           <param name=”bufferSize”>1024</param>

       </result>  

   </action>  

</package>

二：然后是action类：

package upload.action;

import java.io.File;

import java.io.FileInputStream;

import java.io.FileOutputStream;

import java.io.InputStream;

import java.util.List;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import org.apache.struts2.ServletActionContext;

import com.opensymphony.xwork2.ActionSupport;

//文件下载   

public class FileDownload extends ActionSupport{

        private static final long serialVersionUID = 1L;

    private String fileName;

    private int number;

    public InputStream getDownloadFile() throws Exception{

    int number=1;

    //从这是把数据写入到文档中——- 开始

    String str=”afsdasdfasdfadfaaaaaaaaaaaaaaafasdfasdfasdfasfasdfasdfasdf!”;

        File txt=new File(“D:/attachment/report/Test.txt”);

        if(!txt.exists()){//如果不存在就创建一个文件

            txt.createNewFile();

        }

        byte bytes[]=new byte[512];

        bytes=str.getBytes();

        int b=str.length();

        FileOutputStream fos=new FileOutputStream(txt);

        fos.write(bytes,0,b);//通过流写入硬盘

        fos.close();

        //从这是把数据写入到文档中——- 结束

        

    

        //从这是把上面存到硬盘的文件下载下来——– 开始

          String path = “D:/attachment/”;

      //if(number == 1){

              path += “report/”;

      //}

     // String aId = ServletActionContext.getRequest().getParameter(“attachId”);//保存的id

         //List<Attachment> attaList = attachmentService.findAttachmentById(aId);

         

         //Attachment attachment = attaList.get(0);

         //String aName=attachment.getGeneratedfilenamedirectory();

         String aName=”Test.txt”;

         //String fileName=attachment.getOriginalname();

         String fileName=”Test.txt”;

     // 如果下载文件名为中文，进行字符编码转换

         ServletActionContext.getResponse().setHeader(“Content-Disposition”,”attachment;fileName=”+ new String(fileName.getBytes(“gb2312”), “ISO8859-1” ));

         File file = new File(path+aName);

         if(!file.exists()){

             return null;

         }

         InputStream inputStream = new FileInputStream(file);

         return inputStream;

    //从这是把上面存到硬盘的文件下载下来——– 结束

  }

  @Override  

  public String execute() throws Exception {

      return SUCCESS;

  }

}

三：action调用，在前台直接写action地址：

window.location.href=”${pageContext.request.contextPath }/download_execute.action;

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