示例文件下载demo

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package com.js.ai.modules.shwindow.util;

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileInputStream;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
 * 
 * @ClassName: DownloadCsv
 * @Description: 下载 csv文件工具类
 * @author:
 * @date: 
 */
public class DownloadCsv {
	/**
	 * 
	 * @Title: downloadCsv
	 * @Description: TODO下载 csv文件
	 * @param request
	 * @param response
	 * @param fileName
	 * @throws Exception
	
	 * @return: void
	 */
public static void downloadCsv(HttpServletRequest request, HttpServletResponse response,String fileName ) throws Exception{
		
		response.setContentType("text/html;charset=UTF-8");
		BufferedInputStream in = null;
		BufferedOutputStream out = null;
		request.setCharacterEncoding("UTF-8");
		String rootpath = request.getSession().getServletContext().getRealPath("/");
		try {
			File f = new File(rootpath + "folder/" + fileName);
			response.setContentType("application/x-excel");
			response.setCharacterEncoding("UTF-8");
			response.setHeader("Content-Disposition", "attachment; filename=" + fileName);
			response.setHeader("Content-Length", String.valueOf(f.length()));
			in = new BufferedInputStream(new FileInputStream(f));
			out = new BufferedOutputStream(response.getOutputStream());
			byte[] data = new byte[1024];
			int len = 0;
			while (-1 != (len = in.read(data, 0, data.length))) {
				out.write(data, 0, len);
			}
		} catch (Exception e) {
			e.printStackTrace();  
		} finally {
			if (in != null) {
				in.close();
			}
			if (out != null) {
				out.close();
			}
		}
	}

}