Java Socket programming-Get website homepage information

Today, I will write an article every week, from the simplest socket connection to file transmission to protocol implementation,

Remote Desktop control, describes all aspects of Java socket programming and a variety of skills, from common

Socket to Java NIO.

 

This is the first article, which describes how to obtain the home page of a website through Java Socket, including

How to obtain the local machine name and IP address, and how to establish a socket to connect to a remote WEB site

How to Use the http get method to obtain the website homepage content and HTTP Response Headers. Program running result:

 

From this, we can know what language the csdn website is developed based on, what the server is, and what the version is.

For details, refer to the source code:

[Java]
Package com. gloomyfish. socket. tutorial. one;
 
Import java. io. BufferedReader;
Import java. io. BufferedWriter;
Import java. io. IOException;
Import java. io. InputStreamReader;
Import java. io. OutputStreamWriter;
Import java.net. InetAddress;
Import java.net. InetSocketAddress;
Import java.net. Socket;
Import java.net. SocketAddress;
Import java.net. UnknownHostException;
 
Public class HomePageVisitor {
Private Socket client;
Private SocketAddress address;
Public HomePageVisitor (String hostName, int port) throws UnknownHostException, IOException {
Client = new Socket ();
Address = new InetSocketAddress (hostName, port );
}
// GET http: // localhost: 8080/blank/Welcome. do HTTP/1.1/r \ n
Public void printHomePageInfo (String httpString)
{
Try {
// Get local host info
InetAddress inetAddress = InetAddress. getLocalHost ();
System. out. println ("Host Address =" + inetAddress. getHostAddress ());
System. out. println ("Hostname =" + inetAddress. getHostName ());

// Visit the WEBSITE
Client. connect (address );
BufferedWriter bufferedWriter = new BufferedWriter (new OutputStreamWriter (client. getOutputStream (), "UTF8 "));
BufferedWriter. write (httpString );

// -- HTTP/1.1 400 Bad Request if not send \ r \ n
BufferedWriter. write ("\ r \ n ");
BufferedWriter. flush ();
System. out. println ("http request send out ");

BufferedReader bufferedReader = new BufferedReader (new InputStreamReader (client. getInputStream ()));
String content = null;
While (content = bufferedReader. readLine ())! = Null ){
If (getStatusCde (content) = 400 ){
System. err. println ("HTTP/1.1 | HTTP/1.0 400 Bad Request ");
Break;
}
System. out. println ("response contect -->" + content );
}
} Catch (Exception e ){
E. printStackTrace ();
}

}

/**
* <P> try to parse the HTTP response content </p>
* @ Param content
* @ Return status of HTTP
*/
Private static int getStatusCde (String content ){
Int status = 200; // default OK response
If (content = null | "". equals (content ))
Return status;
Else if (! Content. contains ("HTTP/1.1 ")&&! Content. contains ("HTTP/1.0 "))
Return status;
Else if (content. contains ("400") & content. contains ("HTTP/1.1 ")
| Content. contains ("HTTP/1.0 ")){
Status = 400;
}
Return status;
}

Public static void main (String [] args ){
Try {
HomePageVisitor httpVisitor = new HomePageVisitor ("www.csdn.net", 80 );
HttpVisitor. printHomePageInfo ("GET http://www.csdn.net HTTP/1.0 \ r \ n ");
} Catch (UnknownHostException e ){
E. printStackTrace ();
} Catch (IOException e ){
E. printStackTrace ();
}
}
}
If a proxy is used, the HTTP Proxy Address and port are used during Address initialization.
The proxy automatically forwards http get requests. The Code is as follows:

[Java]
Address = new InetSocketAddress (http_proxy, proxy_port)