Java网络编程

package com.net;

import java.io.*;
import java.net.*;
import java.util.Date;
import java.util.HashMap;
import java.util.Map;

public class JavaNet {

	/**
	 * 根据域名获取IP
	 * 
	 * @param realmName 域名
	 * @return IP
	 */
	public static String GetIP(String realmName) {
		InetAddress address;
		try {
			address = InetAddress.getByName(realmName);
		} catch (UnknownHostException e) {
			return null;
		}
		return address.getHostAddress();
	}

	/**
	 * 获取端口是否被占用
	 * 
	 * @param host IP
	 * @param port 端口号
	 * @return 端口的使用状态
	 */
	public static boolean PortIsUsed(String host, int port) {
		try {
			Socket socket = new Socket(host, port);
			return true;
		} catch (UnknownHostException e) {
		} catch (IOException e) {
		}
		return false;
	}

	/**
	 * 获取本机IP
	 * 
	 * @return 本机IP地址
	 * @throws UnknownHostException 异常
	 */
	public static String LocalHostAddress() throws UnknownHostException {
		InetAddress address = InetAddress.getLocalHost();
		return address.getHostAddress();
	}

	/**
	 * 获取本机的主机名
	 * 
	 * @return 主机名
	 * @throws UnknownHostException 异常
	 */
	public static String LocalHostName() throws UnknownHostException {
		InetAddress address = InetAddress.getLocalHost();
		return address.getHostName();
	}

	/**
	 * 获取远程文件大小
	 * 
	 * @param fileLocal 文件路径
	 * @return 文件大小,单位为bytes
	 * @throws IOException 异常
	 */
	public static int getHostFileSize(String fileLocal) throws IOException {
		int size;
		URL url = new URL(fileLocal);
		URLConnection conn = url.openConnection();
		size = conn.getContentLength();
		conn.getInputStream().close();
		return size;
	}

	/**
	 * 获取文件的最后修改日期
	 * 
	 * @param fileLocal 文件路径
	 * @return 最后修改日期
	 * @throws IOException 异常
	 */
	public static Date getFileLastEditDate(String fileLocal) throws IOException {
		URL url = new URL(fileLocal);
		URLConnection conn = url.openConnection();
		conn.setUseCaches(false);
		long timestamp = conn.getLastModified();
		conn.getInputStream().close();
		Date date = new Date(timestamp);
		return date;
	}

	/**
	 * 网页抓取
	 * 
	 * @param local 抓取的路径
	 * @param htmlName html名 可为空
	 * @return 抓取的结果
	 * @throws IOException 异常
	 */
	public static String getHtmlText(String local, String htmlName) throws IOException {
		if (!local.contentEquals("http://"))
			return "local error,like http://www.xxx.com";
		if (htmlName == null)
			htmlName = "data.html";
		URL url = new URL(local);
		BufferedReader reader = new BufferedReader(new InputStreamReader(url.openStream()));
		BufferedWriter writer = new BufferedWriter(new FileWriter(htmlName));
		String line;
		StringBuffer stringBuffer = new StringBuffer();
		while ((line = reader.readLine()) != null) {
			stringBuffer.append("\n" + line);
			writer.write(line);
			writer.newLine();
		}
		String result = stringBuffer.toString().replaceFirst("\n", "");
		reader.close();
		writer.close();
		return result;
	}

	/**
	 * 获取相应头信息
	 * 
	 * @param local 请求路径 携带http://
	 * @return 响应头信息
	 * @throws IOException 异常
	 */
	public static Map getHeaders(String local) throws IOException {
		URL url = new URL(local);
		URLConnection conn = url.openConnection();
		Map headers = conn.getHeaderFields();
		return headers;
	}

	/**
	 * 解析URL
	 * 
	 * @param local 请求路径
	 * @return url信息
	 * @throws MalformedURLException 异常
	 */
	public static Map getURLInfo(String local) throws MalformedURLException {
		URL url = new URL(local);
		Map map = new HashMap();
		map.put("url", url.toString());
		// 协议
		map.put("protocol", url.getProtocol());
		// 文件名
		map.put("file", url.getFile());
		// 主机
		map.put("host", url.getHost());
		// 路径
		map.put("path", url.getPath());
		// 端口号
		map.put("port", url.getPort());
		// 默认端口号
		map.put("defaultPort", url.getDefaultPort());
		return map;
	}

}


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