servlet文件下載+驗證碼

代碼倉庫地址+文檔：https://gitee.com/DerekAndroid/ServletDownload.git

servlet文件下載

package com.itheima.servlet;

import java.io.IOException;
import java.io.InputStream;
import java.net.URLEncoder;

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

public class DownLoadServlet extends HttpServlet {
	private static final long serialVersionUID = 1L;

	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		//獲取文件名
		String filename = request.getParameter("filename");
		//獲取ServletContext對象
		ServletContext sc = getServletContext();
		//通過對象的getMimeType方法獲取mime類型
		String mimeType = sc.getMimeType("/"+filename);
		//設置文件的mime類型頭
		response.setHeader("content-type", mimeType);
		//獲取瀏覽器的版本內核
		String agent = request.getHeader("user-agent");
		//System.out.println(agent);
		//設置文件下載頭
		response.setHeader("content-disposition", "attachment;filename="+DownLoadUtils.getName(agent, "智力遊戲"));
		//設置流
		//獲取輸入流
		InputStream is = sc.getResourceAsStream("/"+filename);
		//獲取輸出流
		ServletOutputStream os = response.getOutputStream();
		//倆流互拷
		byte[] buf = new byte[1024];
		int len = 0;
		while((len=is.read(buf))!=-1){
			os.write(buf, 0, len);
		}
		//關閉流
		os.close();
		is.close();
	}

	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		doGet(request, response);
	}

}