JAvaとネットワーク(概要)

1.共通クラス

InetAddress

//  getLocalHost    InetAddress      
InetAddress addr = InetAddress.getLocalHost();
System.out.println(addr.getHostAddress());  //  ：192.168.1.110
System.out.println(addr.getHostName());  //      

//      InetAddress  
addr = InetAddress.getByName("www.beeworkshop.com"); 
System.out.println(addr.getHostAddress());  //      ip:
System.out.println(addr.getHostName());  //  ：www.beeworkshop.com

//  ip  InetAddress  
addr = InetAddress.getByName("123.56.78.9"); 
System.out.println(addr.getHostAddress());  //   ip:123.56.138.176
System.out.println(addr.getHostName());  //  ip     。    IP       DNS        IP        ，

InetSocketAddress

//    
InetSocketAddress socketAddress = new InetSocketAddress("127.0.0.1",8080);
InetSocketAddress socketAddress2 = new InetSocketAddress("localhost",9000);
System.out.println(socketAddress.getHostName());
System.out.println(socketAddress.getAddress());
System.out.println(socketAddress2.getAddress());
System.out.println(socketAddress2.getPort());

2.ポート番号

0 0-1023公認ポート(サービスへの割り当て)

1024-49151登録ポート(ユーザプロセスまたはアプリケーションに割り当てる)

49152-65535動的プライベートポート

3. URL
URI=URL+URNアンカー#は、同じページまたは同じサイト内でのジャンプを表します.

URL url = new URL("http://www.baidu.com:80/index.html?uname=shsxt&age=18#a");
//     
System.out.println("  :"+url.getProtocol());
System.out.println("  |ip:"+url.getHost());
System.out.println("  :"+url.getPort());
System.out.println("    1:"+url.getFile());
System.out.println("    2:"+url.getPath());

//  
System.out.println("  :"+url.getQuery());
//  
System.out.println("  :"+url.getRef());

4.Web spider(ネットワーク爬虫類)

基本原理

//  URL
URL url =new URL("https://www.jd.com");
//URL url =new URL("https://www.dianping.com");
//    
InputStream is = url.openStream();
BufferedReader br =new BufferedReader(new InputStreamReader(is,"UTF-8"));
String msg =null;
while(null!=(msg=br.readLine())) {
	System.out.println(msg);
}
br.close();
//  
//  。。。。

アナログブラウザ

//  URL
URL url =new URL("https://www.dianping.com");
//    
HttpURLConnection  conn =(HttpURLConnection) url.openConnection();
conn.setRequestMethod("GET");
//User-Agent         
conn.setRequestProperty("User-Agent","Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36");
BufferedReader br =new BufferedReader(new InputStreamReader(conn.getInputStream(),"UTF-8"));
String msg =null; 
while(null!=(msg=br.readLine())) {
	System.out.println(msg);
}
br.close();
//  
//  。。。。