怎样用java web和websocket实现网页即时通讯

如题所述

第1个回答  2014-12-20
下面是一个java的多线程的WebServer的例子:

//import java.io.*;
import java.net.*;
//import java.util.*;

public final class WebServer {
public static void main(String argv[]) throws Exception
{
int port = 80;
// Establish the listen socket.
ServerSocket WebSocket = new ServerSocket(port);
while (true) {
// Listen for a TCP connection request.
Socket connectionSocket = WebSocket.accept();
//Construct object to process HTTP request message
HttpRequest request = new HttpRequest(connectionSocket);

Thread thread = new Thread(request); //Create new thread to process

thread.start(); //Start the thread

}
}
}

import java.io.*;
import java.net.*;
import java.util.*;

public final class HttpRequest implements Runnable {

final static String CRLF = "\r\n";//For convenience
Socket socket;

// Constructor
public HttpRequest(Socket socket) throws Exception
{
this.socket = socket;
}

// Implement the run() method of the Runnable interface.
public void run()
{
try {
processRequest();
} catch (Exception e) {
System.out.println(e);
}
}

private void processRequest() throws Exception
{
InputStream is = socket.getInputStream(); //Starts the input from client machine

DataOutputStream os = new DataOutputStream(
socket.getOutputStream());

// Set up input stream filters.

BufferedReader br = new BufferedReader(
new InputStreamReader(is));

String requestLine = br.readLine();

System.out.println(); //Echoes request line out to screen
System.out.println(requestLine);

//The following obtains the IP address of the incoming connection.

InetAddress incomingAddress = socket.getInetAddress();
String ipString= incomingAddress.getHostAddress();
System.out.println("The incoming address is: " + ipString);

//String Tokenizer is used to extract file name from this class.
StringTokenizer tokens = new StringTokenizer(requestLine);
tokens.nextToken(); // skip over the method, which should be “GET”
String fileName = tokens.nextToken();
// Prepend a “.” so that file request is within the current directory.
fileName = "." + fileName;

String headerLine = null;
while ((headerLine = br.readLine()).length() != 0) { //While the header still has text, print it
System.out.println(headerLine);
}

// Open the requested file.
FileInputStream fis = null;
boolean fileExists = true;
try {
fis = new FileInputStream(fileName);
} catch (FileNotFoundException e) {
fileExists = false;
}

//Construct the response message
String statusLine = null; //Set initial values to null
String contentTypeLine = null;
String entityBody = null;
if (fileExists) {
statusLine = "HTTP/1.1 200 OK: ";
contentTypeLine = "Content-Type: " +
contentType(fileName) + CRLF;
} else {
statusLine = "HTTP/1.1 404 Not Found: ";
contentTypeLine = "Content-Type: text/html" + CRLF;
entityBody = "<HTML>" + "<HEAD><TITLE>Not Found</TITLE></HEAD>" + "<BODY>Not Found</BODY></HTML>";
}
//End of response message construction

// Send the status line.
os.writeBytes(statusLine);

// Send the content type line.
os.writeBytes(contentTypeLine);

// Send a blank line to indicate the end of the header lines.
os.writeBytes(CRLF);

// Send the entity body.
if (fileExists) {
sendBytes(fis, os);
fis.close();
} else {
os.writeBytes(entityBody);
}

os.close(); //Close streams and socket.
br.close();
socket.close();

}

//Need this one for sendBytes function called in processRequest
private static void sendBytes(FileInputStream fis, OutputStream os)
throws Exception
{
// Construct a 1K buffer to hold bytes on their way to the socket.
byte[] buffer = new byte[1024];
int bytes = 0;

// Copy requested file into the socket’s output stream.
while((bytes = fis.read(buffer)) != -1 ) {
os.write(buffer, 0, bytes);
}
}
private static String contentType(String fileName)
{
if(fileName.endsWith(".htm") || fileName.endsWith(".html"))
return "text/html";
if(fileName.endsWith(".jpg"))
return "text/jpg";
if(fileName.endsWith(".gif"))
return "text/gif";
return "application/octet-stream";
}
}本回答被提问者和网友采纳

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