userequestprocessor.java

实现Web服务器重请求处理功能的java编程

import java.net.*;
import java.io.*;
import java.util.*;
    
public class useRequestProcessor implements Runnable 
{
	//设置属性    
  	private static List pool = new LinkedList();
  	private File documentRootDirectory;
  	private String indexFileName = "index.html";
  
  	//构造器
  	public useRequestProcessor(File documentRootDirectory,String indexFileName) 
  	{
        
    		if (documentRootDirectory.isFile()) 
    		{
      			throw new IllegalArgumentException(
      			"documentRootDirectory must be a directory, not a file");   
    		}
    		//根目录
    		this.documentRootDirectory = documentRootDirectory;
    		try 
    		{
      			this.documentRootDirectory= documentRootDirectory.getCanonicalFile();
    		}
    		catch (IOException e) 
    		{ }
    		if (indexFileName != null) this.indexFileName = indexFileName;
  	}
  
  	public static void processRequest(Socket request) 
  	{
    		//同步
    		synchronized (pool) 
    		{
      			pool.add(pool.size(), request);
      			pool.notifyAll();
    		}
  	}  
  
  	public void run() 
  	{        
    		//安全检查
    		String root = documentRootDirectory.getPath();
      
    		while (true) 
    		{       
      			Socket connection;
      			synchronized (pool) 
      			{         
        			while (pool.isEmpty()) 
        			{
          				try 
          				{
            					pool.wait();
          				}
          				catch (InterruptedException e) 
          				{}
        			}
        			//设置Socket
        			connection = (Socket) pool.remove(0); 
      			}

      			try 
      			{            
        			String filename;
        			String contentType; 
        			//缓冲输出流  
        			OutputStream raw = new BufferedOutputStream(Connection.getOutputStream() );         
        			//新建Writer对象
        			Writer out = new OutputStreamWriter(raw);
        			//输入缓冲
        			Reader in = new InputStreamReader(new 
        			BufferedInputStream(Connection.getInputStream()),"ASCII" );
        			StringBuffer requestLine = new StringBuffer();
        			int c;
        			while (true) 
        			{
        				//读取输入
          				c = in.read();
          				//设置循环中止条件
          				if (c == '\r' || c == '\n') break;
          				requestLine.append((char) c);
        			}
        
        			String get = requestLine.toString();
        
        			// 输出请求 
        			System.out.println(get);
        
        			StringTokenizer st = new StringTokenizer(get);
        			String method = st.nextToken();
        			String version = "";
        			if (method.equals("GET")) 
        			{
        				//获取下一个令牌
          				filename = st.nextToken();
          				if (filename.endsWith("/")) filename += indexFileName;
          				contentType = guessContentTypeFromName(filename);
          				if (st.hasMoreTokens()) 
          				{
            					version = st.nextToken();
          				}

          				File theFile = new File(documentRootDirectory, 
           				filename.substring(1,filename.length()));
          				// 不让客户端在文件根目录之外
          				if (theFile.canRead()              				 
           				&& theFile.getCanonicalPath().startsWith(root)) 
           				{
           					//新建输入流对象
            					DataInputStream fis = new DataInputStream(
                                   		new BufferedInputStream(
                                    		new FileInputStream(theFile)));
           					byte[] theData = new byte[(int) theFile.length()];
            					fis.readFully(theData);
            					fis.close();
            					if (version.startsWith("HTTP/")) 
            					{  
            						// 发送一个MIME 头
              						out.write("HTTP/1.0 200 OK\r\n");
              						Date now = new Date();
              						out.write("Date: " + now + "\r\n");
              						out.write("Server: JHTTP 1.0\r\n");
             						out.write("Content-length: " + theData.length + "\r\n");
              						out.write("Content-type: " + contentType + "\r\n\r\n");
              						out.flush();
            					} 
        
            					// 发送文件，可能是图像也可能是其他二进制数据 
            					// 我们采用underlying输出流
            					raw.write(theData);
            					raw.flush();
          				}  // end if
          				else 
          				{
          					// 不能发现文件
            					if (version.startsWith("HTTP/")) 
            					{
            						// 发送一个MIME头
              						out.write("HTTP/1.0 404 File Not Found\r\n");
              						Date now = new Date();
              						out.write("Date: " + now + "\r\n");
              						out.write("Server: JHTTP 1.0\r\n");
              						out.write("Content-type: text/html\r\n\r\n");
            					} 
            					//发送HTML
            					out.write("<HTML>\r\n");
            					out.write("<HEAD><TITLE>File Not Found</TITLE>\r\n");
            					out.write("</HEAD>\r\n");
            					out.write("<BODY>");
            					out.write("<H1>HTTP Error 404: File Not Found</H1>\r\n");
            					out.write("</BODY></HTML>\r\n");
            					out.flush();
          				}
        			}
        			else 
        			{
        				// 不等于"get"方法
          				if (version.startsWith("HTTP/")) 
          				{  
          					// 发送一个 MIME头
            					out.write("HTTP/1.0 501 Not Implemented\r\n");
            					Date now = new Date();
            					out.write("Date: " + now + "\r\n");
            					out.write("Server: JHTTP 1.0\r\n");
            					out.write("Content-type: text/html\r\n\r\n"); 
          				}       
          				out.write("<HTML>\r\n");
          				out.write("<HEAD><TITLE>Not Implemented</TITLE>\r\n");
          				out.write("</HEAD>\r\n");
          				out.write("<BODY>");
          				out.write("<H1>HTTP Error 501: Not Implemented</H1>\r\n");
          				out.write("</BODY></HTML>\r\n");
          				out.flush();
        			}
      			}
      			catch (IOException e) 
      			{}
      			finally 
      			{
        			try 
        			{
        				//关闭连接
          				connection.close();        
        			}
        			catch (IOException e) 
        			{} 
      			}      
    		} // end while

  	} // end run

  	public static String guessContentTypeFromName(String name) 
  	{
  		//返回文件类型
    		if (name.endsWith(".html") || name.endsWith(".htm")) 
    		{
      			return "text/html";
    		}
    		else if (name.endsWith(".txt") || name.endsWith(".java")) 
    		{
      			return "text/plain";
    		}
    		else if (name.endsWith(".gif")) 
    		{
      			return "image/gif";
    		}
    		else if (name.endsWith(".class")) 
    		{
      			return "application/octet-stream";
    		}
    		else if (name.endsWith(".jpg") || name.endsWith(".jpeg")) 
    		{
      			return "image/jpeg";
    		}
    		else return "text/plain";
  	}  

} // end useRequestProcessor