A Simple Web Server

HTTP：Http允许Web服务器和浏览器通过Internet发送并接收数据，是一种基于“请求 - 响应”的协议。

一、HTTP 请求

• 请求方法  - URI - 协议/版本
• 请求头
• 实体

二、HTTP 响应

• 协议 - 状态码 - 描述
• 响应头
• 响应实体段

package org.http; 2  3 import java.io.File; 4 import java.io.IOException; 5 import java.io.InputStream; 6 import java.io.OutputStream; 7 import java.net.ServerSocket; 8 import java.net.Socket; 9 10 public class HttpServer11 {12     public static final String WEB_ROOT = System.getProperty("user.dir")13             + File.separator + "WebContent";14 15     private static final String SHUTDOWN_COMMAND = "/SHUTDOWN";16 17     private final int PORT = 8080;18 19     private boolean shutdown = false;20 21     public static void main(String[] args)22     {23         HttpServer server = new HttpServer();24         server.await();25     }26 27     public void await()28     {29         ServerSocket serverSocket = null;30         try31         {32             serverSocket = new ServerSocket(PORT);33         }34         catch (IOException e)35         {36             e.printStackTrace();37             System.exit(1);38         }39         // Loop waitting for a request40         while (!shutdown)41         {42             Socket socket = null;43             InputStream input = null;44             OutputStream output = null;45             try46             {47                 socket = serverSocket.accept();48                 input = socket.getInputStream();49                 output = socket.getOutputStream();50                 51                 // create request object and parse52                 Request request = new Request(input);53                 request.parse();54                 55                 // create response object56                 Response response = new Response(output);57                 response.setRequest(request);58                 response.sendStaticResource();59                 shutdown = request.getUri().equals(SHUTDOWN_COMMAND);60             }61             catch (IOException e)62             {63                 e.printStackTrace();64             }65             finally66             {67                 try68                 {69                     socket.close();70                 }71                 catch (IOException e)72                 {73                     e.printStackTrace();74                 }75             }76 77         }78     }79 }

package org.http; 2  3 import java.io.IOException; 4 import java.io.InputStream; 5  6 public class Request 7 { 8     private InputStream input; 9     private String uri;10 11     public Request(InputStream input)12     {13         this.input = input;14     }15 16     public void parse()17     {18         StringBuffer request = new StringBuffer(2048);19         int i;20         byte[] buffer = new byte[2048];21         try22         {23             i = input.read(buffer);24         }25         catch (IOException e)26         {27             e.printStackTrace();28             i = -1;29         }30         for (int j = 0; j < i; j++)31         {32             request.append((char) buffer[j]);33         }34         System.out.println(request.toString());35         uri = parseUri(request.toString());36     }37 38     private String parseUri(String requestStr)39     {40         int index1, index2;41         index1 = requestStr.indexOf(' ');42         if (index1 != -1)43         {44             index2 = requestStr.indexOf(' ', index1 + 1);45             if (index2 > index1)46             {47                 return requestStr.substring(index1 + 1, index2);48             }49         }50         return "";51     }52 53     public String getUri()54     {55         return uri;56     }57 }

package org.http; 2  3 import java.io.File; 4 import java.io.FileInputStream; 5 import java.io.IOException; 6 import java.io.OutputStream; 7  8 public class Response 9 {10     private static final int BUFFER_SIZE = 1024;11     private Request request;12     private OutputStream output;13 14     public Response(OutputStream output)15     {16         this.output = output;17     }18 19     public void sendStaticResource()20     {21         byte[] bytes = new byte[BUFFER_SIZE];22         FileInputStream fis = null;23         try24         {25             File file = new File(HttpServer.WEB_ROOT, request.getUri());26 27             if (file.exists())28             {29                 fis = new FileInputStream(file);30                 int ch = fis.read(bytes, 0, BUFFER_SIZE);31                 while (ch != -1)32                 {33                     output.write(bytes, 0, ch);34                     ch = fis.read(bytes, 0, BUFFER_SIZE);35                 }36             }37             else38             {39                 String errorMessage = "HTTP/1.1 404 File Not Found\r\n"40                         + "Content-Type : text/html\r\n" + "\r\n"41                         + "<h1>File Not Found</h1>";42                 output.write(errorMessage.getBytes());43             }44         }45         catch (Exception e)46         {47             e.printStackTrace();48         }49         finally50         {51             if (fis != null)52                 try53                 {54                     fis.close();55                 }56                 catch (IOException e)57                 {58                     e.printStackTrace();59                 }60         }61 62     }63 64     public void setRequest(Request request)65     {66         this.request = request;67     }68 }

 

打印HTTP响应： 

package org.http; 2  3 import java.io.BufferedReader; 4 import java.io.IOException; 5 import java.io.InputStream; 6 import java.io.InputStreamReader; 7 import java.io.OutputStream; 8 import java.io.PrintWriter; 9 import java.net.Socket;10 import java.net.UnknownHostException;11 12 public class Client13 {14     public static void main(String[] args) throws Exception15     {16         Socket socket = new Socket("127.0.0.1", 8080);17         OutputStream os = socket.getOutputStream();18         InputStream is = socket.getInputStream();19         boolean autoFlush = true;20         PrintWriter out = new PrintWriter(os, autoFlush);21         BufferedReader in = new BufferedReader(new InputStreamReader(is));22         out.println("Get /index.jsp HTTP/1.1");23         out.println("Host: localhost:8080");24         out.println("Connection: close");25         out.println();26 27         boolean loop = true;28         StringBuffer sb = new StringBuffer(8096);29         while (loop)30         {31             if (in.ready())32             {33                 int i = 0;34                 do35                 {36                     i = in.read();37                     sb.append((char) i);38                 }39                 while (i != -1);40                 loop = false;41             }42             Thread.sleep(1000);43         }44         System.out.println(sb.toString());45         socket.close();46     }47 }