使用BIO創建簡單的http服務器

時間 2019-11-17

原文原文鏈接

平時在使用tomcat、jetty時，只是使用裏面的servlet、filter等，歷來沒想過它們如何同瀏覽器進行交互的。工做中遇到一些問題，在同其它同事交流及學習源碼的過程當中，才明白底層原來走的也是socket，才知道所謂的NIO是什麼。。。html

瞭解NIO以前，確定得先了解BIO，出於學習的目的，使用BIO寫一個簡單的http服務器DEMO：瀏覽器輸入任何請求，後臺打印出請求信息並在瀏覽器中輸出Hello Worldjava

 1 import java.io.BufferedReader;
 2 import java.io.BufferedWriter;
 3 import java.io.IOException;
 4 import java.io.InputStream;
 5 import java.io.InputStreamReader;
 6 import java.io.OutputStream;
 7 import java.io.OutputStreamWriter;
 8 import java.net.InetSocketAddress;
 9 import java.net.ServerSocket;
10 import java.net.Socket;
11 
12 public class BioServer {
13     private ServerSocket serverSocket;
14     
15     private String ip;
16     
17     private int port;
18     
19     public BioServer(String ip, int port) {
20         this.ip = ip;
21         this.port = port;
22     }
23     
24     public void startListen() throws IOException {
25         serverSocket = new ServerSocket();
26         serverSocket.bind(new InetSocketAddress(ip, port)); //建立對指定端口及IP的監聽
27         
28         while (true) {
29             accept();
30         }
31     }
32     
33     private void accept() throws IOException {
34         //收到客戶端的請求
35         Socket socket = serverSocket.accept();
36         
37         //輸入流用於接收客戶端傳輸過來的數據
38         InputStream in = socket.getInputStream();
39         InputStreamReader reader = new InputStreamReader(in);
40         BufferedReader br = new BufferedReader(reader);
41         String line = null;
42         while ((line = br.readLine()) != null) {
43             System.out.println(line);
44             //按照HTTP協議，請求頭和請求體之間爲一空行分隔
45             if ("".equals(line)) {
46                 break;
47             }
48         }
49         
50         //輸出流用於向客戶端發送響應消息，需聽從HTTP協議格式
51         OutputStream out = socket.getOutputStream();
52         OutputStreamWriter writer = new OutputStreamWriter(out);
53         BufferedWriter bw = new BufferedWriter(writer);
54         bw.write("HTTP/1.1 200 OK\n");
55         bw.write("Content-Type: text/html; charset=UTF-8\n");
56         bw.write("\n");
57         bw.write("<html>");
58         bw.write("<head>");
59         bw.write("<title>");
60         bw.write("BIO Http Server");
61         bw.write("</title>");
62         bw.write("</head>");
63         bw.write("<body>");
64         bw.write("<h1>Hello World!</h1>");
65         bw.write("</body>");
66         bw.write("</html>");
67         
68         //必須在請求讀取和響應寫入都處理完畢以後才能夠調用close方法，將輸入流關閉也會致使輸出流不可用
69         bw.close();
70         writer.close();
71         out.close();
72         br.close();
73         reader.close();
74         in.close();
75         socket.close();
76     }
77     
78     public static void main(String[] args) {
79         BioServer server = new BioServer("127.0.0.1", 8080);
80         try {
81             server.startListen();
82         } catch (IOException e) {
83             e.printStackTrace();
84         }
85     }
86 }