URL (Uniform Resource Locator). 3
URL. 5
. 5
. 6
.. 8
Java Network. − TCP/IP.
/ , − , − . − , . - .
TCP/IP IP-. 32- , , , 0 255. IP- , . IP , . DNS (Domain Name Sever) IP-. IP- InetAddress java.net:
// IP-
import java.net.*;
public class MyLocal {
public static void main(String[] args){
InetAddress myIP = null;
try {
myIP = InetAddress.getLocalHost();}
catch (UnknownHostException e) {}
System.out.println(myIP);
}
}
getByName IP- :
// IP-
import java.net.*;
public class IPfromDNS {
public static void main(String[] args){
InetAddress bsu = null;
try {
bsu = InetAddress.getByName("www.ya.ru"); }
catch (UnknownHostException e){ }
System.out.println(bsu);
}
}
IP- , 217.21.43.2:31. 1 1024 , , . , : 20 FTP-, 21 FTP-, 23 TELNET, 53 DNS, 80 HTTP, 110 POP3, 119 NNTP.
URL (Uniform Resource Locator)
URL: http://ya.ru/
:
http . HTTP : File Transfer Protocol (FTP), Gopher, File, News.
ya.ru/ . /index.html)
. , , ( .. HTTP) :
( )
( , ; HTML, -)
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Java URL java.net. url :
URL yandex = new URL("http://ya.ru/");
URL. , , . URL (relative) .
http://news.yandex.ru/Russia/
URL yandex = new URL("http://ya.ru/");
URL yandexRussia = new URL(yandex, "Russia/")
, 4 2 ( ):
new URL("http", "www.gamelan.com", "/pages/Gamelan.net.html");
new URL("http://www.gamelan.com/pages/Gamelan.net.html"); //
:
new URL("http", "www.gamelan.com", 80, "pages/Gamelan.network.html");
// : http://www.gamelan.com:80/pages/Gamelan.network.html
(, ), URL ( = %20). java.net.URI, toURL() URL:
// http://foo.com/hello world/
URI uri = new URI("http", "foo.com", "/hello world/", "");
URL url = uri.toURL();
URL - MalformedURLException.
URL:
getProtocol
getAuthority
( ya.ru:80)
getHost
getPort
. , -1
getPath
getQuery
query
getFile
getPath getQuery (, )
getRef
URL .
:
import java.net.*;
import java.io.*;
public class ParseURL {
public static void main(String[] args) throws Exception {
URL aURL = new URL("http://java.sun.com:80/docs/books/tutorial"
+ "/index.html?name=networking#DOWNLOADING");
System.out.println("protocol = " + aURL.getProtocol());
System.out.println("authority = " + aURL.getAuthority());
System.out.println("host = " + aURL.getHost());
System.out.println("port = " + aURL.getPort());
System.out.println("path = " + aURL.getPath());
System.out.println("query = " + aURL.getQuery());
System.out.println("filename = " + aURL.getFile());
System.out.println("ref = " + aURL.getRef());
}
}
:
protocol = http
authority = java.sun.com:80
host = java.sun.com
port = 80
path = /docs/books/tutorial/index.html
query = name=networking
filename = /docs/books/tutorial/index.html?name=networking
ref = DOWNLOADING
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openStream() URL ( , , -).
URL
URL openConnection URLConnection ( , , java.net.HttpURLConnection). - , ( URLConnection.connect).
:
try {
URL yahoo = new URL("http://www.yahoo.com/");
URLConnection yahooConnection = yahoo.openConnection();
yahooConnection.connect();
} catch (MalformedURLException e) { // new URL() failed
...
} catch (IOException e) { // openConnection() failed
...
}
connect, .. java , (, getInputStream, getOutputStream), .
URLConnection, , URLConnection.getInputStream ( IO-)
URL yahoo = new URL("http://www.yahoo.com/");
URLConnection yc = yahoo.openConnection();
BufferedReader in = new BufferedReader(new InputStreamReader(yc.getInputStream()));
, , ( getOutputStream), output true ( setDoOutput(true)).
URL url = new URL(args[0]);
URLConnection connection = url.openConnection();
connection.setDoOutput(true);
OutputStreamWriter out = new OutputStreamWriter(connection.getOutputStream());
− , . IP-. IP- , , . , . , . , . , , . , , . .
Socket. IP- (80 HTTP). , Java DNS- IP-:
try { socket = new Socket("localhost",8080); }
catch (IOException e){ System.out.println(": " + e); }
. ServerSocket accept(), :
Socket socket = null;
try { server = new ServerSocket(8080);
socket = server.accept(); }
catch (IOException e) { System.out.println(": " + e); }
getInputStram() getOutputStram() PrintStream , .
"!" getOutputStream() Socket. getInputStream(). close() Socket. ! .
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import java.io.*;
import java.net.*;
public class MyServerSocket{
public static void main(String[] args) throws Exception{
Socket s = null;
try {//
ServerSocket server = new ServerSocket(8030);
s = server.accept();
PrintStream ps = new PrintStream(s.getOutputStream());
ps.println("!");
ps.flush();
s.close(); //
}catch (IOException e){System.out.println(": " + e); }
}
}
:
import java.io.*;
import java.net.*;
public class MyClientSocket {
public static void main(String[] args) {
Socket socket = null;
try {//
socket = new Socket("www.bsu.by", 8080);
BufferedReader dis = new BufferedReader(new
InputStreamReader(socket.getInputStream()));
String msg = dis.readLine();
System.out.println(msg);
} catch (IOException e) {System.out.println(": " + e); }
}
}
getOutputStream(), getInputStream().
, , getLocalHost() InetAddress IP- , Internet.
1. -. .
(IP nickname) , .
2. -. .
, nickname ( ) IP .
( ) .
3. 2 :
a. , -
b. , ftp- ( ftp- ).
4. SMTP.
5. POP3.
