Servlet 06响应头信息

响应头信息：

协议，状态码，header......

setHeader设置响应头信息

设置内容类型，如word，excel，txt等等

1.构建excel电子表格

代码如下：

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1. public void doGet(HttpServletRequest request, HttpServletResponse response)  
2.             throws ServletException, IOException {  
3.             response.setContentType("application/vnd.ms-excel");  
4.         PrintWriter out = response.getWriter();  
5.           out.println("\tQ1\tQ2\tQ3\tQ4\tTotal");  
6.           out.println("Apples\t78\t87\t92\t29\t=SUM(B2:E2)");  
7.           out.println("Oranges\t77\t86\t93\t30\t=SUM(B3:E3)");  
8.           
9.     }  
10.   
11.     public void doPost(HttpServletRequest request, HttpServletResponse response)  
12.             throws ServletException, IOException {  
13.       doGet(request,response);  
14.             
15.     }  

public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {response.setContentType("application/vnd.ms-excel");    PrintWriter out = response.getWriter();  out.println("\tQ1\tQ2\tQ3\tQ4\tTotal");  out.println("Apples\t78\t87\t92\t29\t=SUM(B2:E2)");  out.println("Oranges\t77\t86\t93\t30\t=SUM(B3:E3)");}public void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {      doGet(request,response);  }

2.动态生成jpeg图片

代码内容如下：

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1.          public void doGet(HttpServletRequest request, HttpServletResponse response)  
2.         throws ServletException, IOException {  
3.       //响应动态图片  
4.       response.setContentType("image/jpeg");                                               //设置响应头响应内容类型为图片  
5.   
6.                   /*this.getClass().getClassLoader().getResourceAsStream()路径采用相对路径直接可以从工程的path路径去找。  
7.        * 这里name是资源的类路径，它是相对与“/”根路径下的位置。getResource得到的是一个URL对象来定位资源，  
8.        * 而getResourceAsStream取得该资源输入流的引用保证程序可以从正确的位置抽取数据  
9.        * */  
10.       InputStream in = this.getClass().getClassLoader().getResourceAsStream("girl.jpeg");  //获得输入流图片  
11.       int len = in.available();                                                            //统计字节长度  
12.       byte[] buffer = new byte[len];  
13.       in.read(buffer);                                                                     //读取字符节  
14.       OutputStream out = response.getOutputStream();                                       //输出流  
15.       out.write(buffer);                                                                   //向输出流中写入字节信息  
16.       out.flush();  
17.       out.close();  
18. }  
19.   
20. public void doPost(HttpServletRequest request, HttpServletResponse response)  
21.         throws ServletException, IOException {  
22.         doGet(request,response);  
23.         
24. }  

          public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {  //响应动态图片  response.setContentType("image/jpeg");                                               //设置响应头响应内容类型为图片                   /*this.getClass().getClassLoader().getResourceAsStream()路径采用相对路径直接可以从工程的path路径去找。   * 这里name是资源的类路径，它是相对与“/”根路径下的位置。getResource得到的是一个URL对象来定位资源，   * 而getResourceAsStream取得该资源输入流的引用保证程序可以从正确的位置抽取数据   * */  InputStream in = this.getClass().getClassLoader().getResourceAsStream("girl.jpeg");  //获得输入流图片  int len = in.available();                                                            //统计字节长度  byte[] buffer = new byte[len];  in.read(buffer);                                                                     //读取字符节  OutputStream out = response.getOutputStream();                                       //输出流  out.write(buffer);                                                                   //向输出流中写入字节信息  out.flush();  out.close();}public void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {         doGet(request,response);  }

3.定时刷新页面

代码内容如下：

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1.              //3.定时刷新页面  
2. response.setHeader("refresh", "1");//每隔1秒刷新一次  
3. response.setContentType("text/html;charset=gbk");  
4. PrintWriter out = response.getWriter();  
5. out.println("<!DOCTYPE HTML>");  
6. out.println("<html>");  
7. out.println("<head><title>Refresh Servlet</title></head>");  
8. out.println("<body>");  
9. out.print("当前刷新时间为：");  
10. out.print(new Date().toLocaleString());  
11. out.println("</body>");  
12. out.println("</html>");  

                 //3.定时刷新页面  response.setHeader("refresh", "1");//每隔1秒刷新一次  response.setContentType("text/html;charset=gbk");  PrintWriter out = response.getWriter();  out.println("<!DOCTYPE HTML>");  out.println("<html>");  out.println("<head><title>Refresh Servlet</title></head>");  out.println("<body>");  out.print("当前刷新时间为：");  out.print(new Date().toLocaleString());  out.println("</body>");  out.println("</html>");

比如一个直播NBA视频，当前时间两队的比分的显示。