文件下载示例

最新推荐文章于 2025-10-25 16:47:10 发布

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#servlet #下载 #io #response

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本文介绍了一个简单的Java Web图片下载示例，通过使用Servlet来处理HTTP请求，并将指定路径下的图片文件返回给客户端。该示例展示了如何设置HTTP响应头以支持文件下载，以及如何读取文件并将其发送到客户端。

文件所在位置:/DownLoadDemo/WebRoot/download/001.jpg

///DownLoadDemo/src/com/huowolf/DownLoadServlet.java

package com.huowolf;

import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class DownLoadServlet extends HttpServlet {


	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {

		response.setContentType("text/html;charset=UTF-8");

		String path = this.getServletContext().getRealPath("/download/001.jpg");
		String filename = path.substring(path.lastIndexOf("\\")+1);
		
		//response.setHeader("Content-Type", "application/octet-stream");
		response.setContentType("application/x-msdownload");
		response.setHeader("Content-Disposition", "attachment;filename="+filename);		
		
		InputStream in = null;
		OutputStream out = response.getOutputStream();
		out.write("下载示例".getBytes());
		
		
		try {
			in = new FileInputStream(path);
			int len=-1;
			byte buffer[] = new byte[1024];
			while((len=in.read(buffer))!=-1) {
				out.write(buffer,0,len);
			}
		} catch (Exception e) {
			e.printStackTrace();
		}finally {
			if(in!=null) {
				try {
					in.close();
					out.close();
				} catch (Exception e) {
					e.printStackTrace();
				}
			}
		}
				
	}


	public void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {

		doGet(request, response);
	}

}