java網路程式設計中常用的類
阿新 • • 發佈：2018-11-12
java網路程式設計中常用的類
1、InetAddress
用於封裝計算機的IP地址和DNS(Domain Name System域名系統)（沒有埠資訊）
InetAddress沒有構造器，要得到物件只能通過靜態方法實現
/** * 使用getLocalHost的方法建立InetAddress物件 */ package com.InetAddress; import java.net.InetAddress; public class Test1 { public static void main(String[] args) throws Exception { InetAddress addr = InetAddress.getLocalHost(); System.out.println("HostAddress:"+addr.getHostAddress()); System.out.println("HostName:"+addr.getHostName()); } } /** * 根據域名得到InetAddress物件 */ package com.InetAddress; import java.net.InetAddress; public class Test2 { public static void main(String[] args) throws Exception { InetAddress addr = InetAddress.getByName("www.sxt.cn");//返回sxt伺服器的ip System.out.println(addr.getHostAddress()); System.out.println(addr.getHostName()); } } /** * 根據IP得到InetAddress物件 */ package com.InetAddress; import java.net.InetAddress; public class Test3 { public static void main(String[] args) throws Exception{ InetAddress addr = InetAddress.getByName("59.110.14.7"); System.out.println(addr.getHostName()); System.out.println(addr.getHostAddress()); } }
2、InetSocketAddress
用於包含IP地址和埠資訊，常用於socket程式設計
package com.InetSocketAddress; import java.net.InetSocketAddress; public class Test1 { public static void main(String[] args) { InetSocketAddress addr1 = new InetSocketAddress("127.0.0.1",8080); InetSocketAddress addr2 = new InetSocketAddress("localhost",9000); System.out.println(addr1.getHostName()); System.out.println(addr2.getAddress()); } } 127.0.0.1 localhost/127.0.0.1
3、URL
統一資源定位符，標識計算機上的資源，是指向網際網路資源的指標
資源可以是簡單的檔案或目錄，也可以是更為複雜的物件引用，例如資料庫或搜尋引擎進行查詢
/** * URL類的使用 */ package com.URL; import java.net.URL; public class Test1 { public static void main(String[] args) throws Exception{ URL u = new URL("http://google.cn.80/webhp#aa?canhu=33"); System.out.println("獲取與此URL關聯的協議預設埠："+u.getDefaultPort()); System.out.println("port:"+u.getPort());//埠，如果是www.google.cn:80 則返回80，否則返回-1 System.out.println("file:"+u.getFile());//埠後面的內容 System.out.println("path:"+u.getPath());//路徑，埠號後、引數前的內容 System.out.println("protocol:"+u.getProtocol());//協議 System.out.println("query:"+u.getQuery());//引數部分 System.out.println("host:"+u.getHost());//主機名 System.out.println("ref:"+u.getRef());//描點 URL u1 = new URL("http://www.abc.com/aa/"); URL u2 = new URL(u1,"a.html"); System.out.println(u2.toString()); } } 獲取與此URL關聯的協議預設埠：80 port:-1 file:/webhp path:/webhp protocol:http query:null host:google.cn.80 ref:aa?canhu=33 http://www.abc.com/aa/a.html
4、最簡單的網路爬蟲
/**
* 最簡單的網路爬蟲
*/
package com.BasicSpider;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.MalformedURLException;
import java.net.URL;
public class Test1 {
public static void main(String[] args) {
URL url = null;
InputStream is = null;
BufferedReader br = null;
StringBuilder sb = new StringBuilder();
String temp = "";
try {
url = new URL("http://www.baidu.com");
is = url.openStream();
br = new BufferedReader(new InputStreamReader(is));
while((temp=br.readLine())!=null){
sb.append(temp);
}
System.out.println(sb);
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}finally {
try {
br.close();
is.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
<!DOCTYPE html><!--STATUS OK--><html> <head><meta http-equiv=content-type content=text/html;charset=utf-8><meta http-equiv=X-UA-Compatible content=IE=Edge><meta content=always name=referrer><link rel=stylesheet type=text/css href=http://s1.bdstatic.com/r/www/cache/bdorz/baidu.min.css><title>百度一下，你就知道</title></head> <body link=#0000cc> <div id=wrapper> <div id=head> <div class=head_wrapper> <div class=s_form> <div class=s_form_wrapper> <div id=lg> <img hidefocus=true src=//www.baidu.com/img/bd_logo1.png width=270 height=129> </div> <form id=form name=f action=//www.baidu.com/s class=fm> <input type=hidden name=bdorz_come value=1> <input type=hidden name=ie value=utf-8> <input type=hidden name=f value=8> <input type=hidden name=rsv_bp value=1> <input type=hidden name=rsv_idx value=1> <input type=hidden name=tn value=baidu><span class="bg s_ipt_wr"><input id=kw name=wd class=s_ipt value maxlength=255 autocomplete=off autofocus></span><span class="bg s_btn_wr"><input type=submit id=su value=百度一下 class="bg s_btn"></span> </form> </div> </div> <div id=u1> <a href=http://news.baidu.com name=tj_trnews class=mnav>新聞</a> <a href=http://www.hao123.com name=tj_trhao123 class=mnav>hao123</a> <a href=http://map.baidu.com name=tj_trmap class=mnav>地圖</a> <a href=http://v.baidu.com name=tj_trvideo class=mnav>視訊</a> <a href=http://tieba.baidu.com name=tj_trtieba class=mnav>貼吧</a> <noscript> <a href=http://www.baidu.com/bdorz/login.gif?login&tpl=mn&u=http%3A%2F%2Fwww.baidu.com%2f%3fbdorz_come%3d1 name=tj_login class=lb>登入</a> </noscript> <script>document.write('<a href="http://www.baidu.com/bdorz/login.gif?login&tpl=mn&u='+ encodeURIComponent(window.location.href+ (window.location.search === "" ? "?" : "&")+ "bdorz_come=1")+ '" name="tj_login" class="lb">登入</a>');</script> <a href=//www.baidu.com/more/ name=tj_briicon class=bri style="display: block;">更多產品</a> </div> </div> </div> <div id=ftCon> <div id=ftConw> <p id=lh> <a href=http://home.baidu.com>關於百度</a> <a href=http://ir.baidu.com>About Baidu</a> </p> <p id=cp>©2017 Baidu <a href=http://www.baidu.com/duty/>使用百度前必讀</a> <a href=http://jianyi.baidu.com/ class=cp-feedback>意見反饋</a> 京ICP證030173號 <img src=//www.baidu.com/img/gs.gif> </p> </div> </div> </div> </body> </html>
結果：
新聞
hao123
地圖
視訊
貼吧
登入
更多產品
