Zhao yazhi _ java Network Programming (4) URL

Let IE write the server program as the client:

[Java]
Package net. csdn. web;
 
Import java. io. IOException;
Import java. io. PrintWriter;
Import java.net. ServerSocket;
Import java.net. Socket;
 
Public class ServerDemo {
 
/**
* @ Param args
* @ Throws IOException
*/
Public static void main (String [] args) throws IOException {
// TODO Auto-generated method stub
ServerSocket ss = new ServerSocket (9009 );
Socket s = ss. accept ();
System. out. println (s. getInetAddress (). getHostAddress () + "...... conection ");
PrintWriter pwout = new PrintWriter (s. getOutputStream (), true );
Pwout. println ("Access successful ");
S. close ();
// Ss. close ();
}
 
}

Package net. csdn. web;

Import java. io. IOException;
Import java. io. PrintWriter;
Import java.net. ServerSocket;
Import java.net. Socket;

Public class ServerDemo {

/**
* @ Param args
* @ Throws IOException
*/
Public static void main (String [] args) throws IOException {
// TODO Auto-generated method stub
ServerSocket ss = new ServerSocket (9009 );
Socket s = ss. accept ();
System. out. println (s. getInetAddress (). getHostAddress () + "...... conection ");
PrintWriter pwout = new PrintWriter (s. getOutputStream (), true );
Pwout. println ("Access successful ");
S. close ();
// Ss. close ();
}

}

 

Connect socket:

Client:

[Java]
Package net. csdn. web;
 
Import java. io. IOException;
Import java.net. InetSocketAddress;
Import java.net. Socket;
 
Public class ConnectClient {
 
Public static void main (String [] args ){
Try {
Socket s = new Socket ();
InetSocketAddress isa = new InetSocketAddress ("192.168.49.58", 9001 );
S. connect (isa, 5000 );
// Equal to Socket s = new Socket ("192.168.49.58", 9001 ));
} Catch (IOException e ){
// TODO Auto-generated catch block
E. printStackTrace ();
}
}
 
}

Package net. csdn. web;

Import java. io. IOException;
Import java.net. InetSocketAddress;
Import java.net. Socket;

Public class ConnectClient {

Public static void main (String [] args ){
Try {
Socket s = new Socket ();
InetSocketAddress isa = new InetSocketAddress ("192.168.49.58", 9001 );
S. connect (isa, 5000 );
// Equal to Socket s = new Socket ("192.168.49.58", 9001 ));
} Catch (IOException e ){
// TODO Auto-generated catch block
E. printStackTrace ();
}
}

}

Server

[Java]
Package net. csdn. web;
 
Import java. io. IOException;
Import java.net. ServerSocket;
Import java.net. Socket;
 
Public class ConnectServer {
Public static void main (String [] args) throws IOException {
 
ServerSocket ss = new ServerSocket (9002 );
Socket s = ss. accept ();
System. out. println (s. getInetAddress (). getHostAddress () + "...... conection ");

}
 
}

Package net. csdn. web;

Import java. io. IOException;
Import java.net. ServerSocket;
Import java.net. Socket;

Public class ConnectServer {
Public static void main (String [] args) throws IOException {

ServerSocket ss = new ServerSocket (9002 );
Socket s = ss. accept ();
System. out. println (s. getInetAddress (). getHostAddress () + "...... conection ");

}

}

 

 

 

URL:

The class URL represents a uniform resource locator, which is a pointer to the Internet "resource. Resources can be simple files or directories, or references to more complex objects.

Two common constructor methods:

URL (String spec): Creates a URL object based on the String representation.
URL (URL context, String spec): Creates a URL by parsing the specified spec in the specified context.

Example:

URL url = new URL ("http://www.baidu.com ");

Relative URL objects are generally used in HTML files, for example:

URL urlbaidu = new URL ("http://www.baidu.com ");

URL urlbaidu_a = new URL (urlbaidu, "a.html ");

URL urlbaidu_ B = new URL (urlbaidu, "B .html ");

Common call methods for accessing resources corresponding to a URL:

String getFile (): get the name of the URL file.
String getHost (): Obtain the Host Name of the URL (if applicable ).
String getPath (): Obtain the path of this URL.
Int getPort (): gets the port number of this URL.
String getProtocol (): gets the protocol name of this URL.
String getQuery (): Obtain the query part of this URL.
URLConnection openConnection (): returns a URLConnection object, which indicates the connection to the remote object referenced by the URL.
InputStream openStream (): Open the connection to this URL and return an InputStream used to read from this connection.

[Java]
Package net. csdn. web;
 
Import java.net. MalformedURLException;
Import java.net. URL;
 
Public class UrlDemo {
 
/**
* @ Param args
*/
Public static void main (String [] args ){
// TODO Auto-generated method stub
 
Try {
URL url = new URL ("http://dianying.taobao.com /? Spm = 1.1000386.221827.9 ");
System. out. println ("protocol =" + url. getProtocol ());
System. out. println ("authority =" + url. getAuthority ());
System. out. println ("host =" + url. getHost ());
System. out. println ("port =" + url. getPort ());
System. out. println ("path =" + url. getPath ());
System. out. println ("query =" + url. getQuery ());
System. out. println ("filename =" + url. getFile ());
System. out. println ("ref =" + url. getRef ());
} Catch (MalformedURLException e ){
// TODO Auto-generated catch block
E. printStackTrace ();
}

}
 
}

Package net. csdn. web;

Import java.net. MalformedURLException;
Import java.net. URL;

Public class UrlDemo {

/**
* @ Param args
*/
Public static void main (String [] args ){
// TODO Auto-generated method stub

Try {
URL url = new URL ("http://dianying.taobao.com /? Spm = 1.1000386.221827.9 ");
System. out. println ("protocol =" + url. getProtocol ());
System. out. println ("authority =" + url. getAuthority ());
System. out. println ("host =" + url. getHost ());
System. out. println ("port =" + url. getPort ());
System. out. println ("path =" + url. getPath ());
System. out. println ("query =" + url. getQuery ());
System. out. println ("filename =" + url. getFile ());
System. out. println ("ref =" + url. getRef ());
} Catch (MalformedURLException e ){
// TODO Auto-generated catch block
E. printStackTrace ();
}

}

}

 

Download webpage information through URL

[Java]
Package net. csdn. web;
 
Import java. io. BufferedReader;
Import java. io. FileOutputStream;
Import java. io. IOException;
Import java. io. InputStreamReader;
Import java.net. URL;
 
Public class TestNet3 {
Public static void main (String [] args) throws IOException {
URL url = new URL ("http://www.baidu.com /");
InputStreamReader isr = new InputStreamReader (url. openStream ());
BufferedReader in = new BufferedReader (isr );
String inputLine;
FileOutputStream fos = new FileOutputStream ("d: \ abc.html ");

While (inputLine = in. readLine ())! = Null ){
Fos. write (inputLine. getBytes ());
System. out. println (inputLine );
}
In. close ();
}
}

Package net. csdn. web;

Import java. io. BufferedReader;
Import java. io. FileOutputStream;
Import java. io. IOException;
Import java. io. InputStreamReader;
Import java.net. URL;

Public class TestNet3 {
Public static void main (String [] args) throws IOException {
URL url = new URL ("http://www.baidu.com /");
InputStreamReader isr = new InputStreamReader (url. openStream ());
BufferedReader in = new BufferedReader (isr );
String inputLine;
FileOutputStream fos = new FileOutputStream ("d: \ abc.html ");

While (inputLine = in. readLine ())! = Null ){
Fos. write (inputLine. getBytes ());
System. out. println (inputLine );
}
In. close ();
}
}

 

The garbled characters in the java address bar are converted to common characters:

 

The URLDecoder class has a static method of decode (String s, String enc): Convert garbled special characters into common characters.

The URLEncoder class has a static method of encode (String s, String enc): Convert common characters into special characters with garbled characters.

[Java]
Package net. csdn. web;
 
Import java. io. UnsupportedEncodingException;
Import java.net. URLDecoder;
Import java.net. URLEncoder;
 
Public class TestNet4 {
 
/**
* @ Param args
*/
Public static void main (String [] args ){

Try {
String str1 = URLEncoder. encode ("java program development", "UTF-8 ");
System. out. println (str1 );

String str2 = URLDecoder. decode ("java % E7 % A8 % 8B % E5 % BA % 8F % E5 % BC % 80% E5 % 8F % 91", "UTF-8 ");
System. out. println (str2 );
} Catch (UnsupportedEncodingException e ){
// TODO Auto-generated catch block
E. printStackTrace ();
}



}
 
}

Package net. csdn. web;

Import java. io. UnsupportedEncodingException;
Import java.net. URLDecoder;
Import java.net. URLEncoder;

Public class TestNet4 {

/**
* @ Param args
*/
Public static void main (String [] args ){
 
Try {
String str1 = URLEncoder. encode ("java program development", "UTF-8 ");
System. out. println (str1 );

String str2 = URLDecoder. decode ("java % E7 % A8 % 8B % E5 % BA % 8F % E5 % BC % 80% E5 % 8F % 91", "UTF-8 ");
System. out. println (str2 );
} Catch (UnsupportedEncodingException e ){
// TODO Auto-generated catch block
E. printStackTrace ();
}
 
 
 
}

}