（五）——Response

 1 package my.tomcat2;
 2 
 3 import java.io.BufferedWriter;
 4 import java.io.IOException;
 5 import java.io.OutputStreamWriter;
 6 import java.net.Socket;
 7 import java.util.Date;
 8 
 9 /**
10  * 用来反馈客户端，也就是想在客户端上显示什么信息
11  */
12 public class Response {
13     //构建 响应头信息需要的一些小零件，这里可以在网上查看下 HTTP 协议
14     private static final String CRLF = "\r\n";
15     private static final String BLANK = " ";
16     //这里是正文，也就是显示在页面上的信息
17     private StringBuilder context;
18     //这里是构建 响应头信息
19     private StringBuilder headInfo;
20     //因为头信息最后会需要 正文的 字节长度，是字节长度，不是字符长度
21     private int len;
22     //用来反馈到客户端上的 输出流
23     private BufferedWriter bw;
24     private String msg;
25     //状态码，这里如上查询 HTTP 协议
26     private int code;
27 
28     //初始化 字段
29     public Response(Socket client) {
30         context = new StringBuilder();
31         headInfo = new StringBuilder();
32         try {
33             bw = new BufferedWriter(new OutputStreamWriter(client.getOutputStream()));
34         } catch (IOException e) {
35             code = 500;
36             return ;
37         }
38     }
39 
40 
41     //构建 响应头部信息
42     public void setHead(int code){
43         headInfo.append("HTTP/1.1").append(BLANK).append(code).append(BLANK);
44         switch (code) {
45             case 200 : headInfo.append("OK").append(CRLF);
46                 break;
47 
48             case 404 : headInfo.append("NOT FOUND").append(CRLF);
49                 break;
50 
51             case 500 : headInfo.append("SERVER ERROR").append(CRLF);
52                 break;
53         }
54         headInfo.append("Server:Feng server/0.01").append(CRLF);
55         headInfo.append("Date:").append(new Date()).append(CRLF);
56         headInfo.append("Content-type:text/html;charset=utf-8").append(CRLF);
57         headInfo.append("Content-Length:" + len).append(CRLF);
58         headInfo.append(CRLF);
59     }
60 
61     //反馈给 客户端 的信息
62     public void print(String msg){
63         context.append(msg);
64         len += msg.getBytes().length;
65     }
66 
67     public void println(String msg){
68         context.append(msg).append(CRLF);
69         len += (msg+CRLF).getBytes().length;
70     }
71     
72     //将 响应头信息+正文 通过流传给 客户端
73     public void pushToClient(int code){
74         if(context == null){
75             code = 500;
76         }
77         this.setHead(code);
78         String responseInfo = headInfo.append(context).toString();
79         try {
80             bw.write(responseInfo);
81             bw.flush();
82         } catch (IOException e) {
83             return ;
84         } finally {
85             CloseUtil.close(bw);
86         }
87     }
88 }