URL标识的资源读取工具

package com.temobi.cds.tool;

import java.io.File;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.net.URL;
import java.net.URLDecoder;
import java.net.URLEncoder;

import org.slf4j.LoggerFactory;

/**
 * URL标识的资源读取工具
 * @author lixu
 *
 */
public class URLResource {

	/**
	 * 拷贝一个远程文件
	 * @param url
	 * @param filePath
	 * @throws Exception
	 */
	public static void copy(String url, String filePath) throws Exception {
		File file = new File(filePath);
		copy(url, file);
	}

	/**
	 * 拷贝一个远程文件
	 * @param url
	 * @param file 要存储到本地的文件
	 * @throws Exception
	 */
	public static void copy(String url, File file) throws Exception {
		boolean ok = true;
		if (!file.getParentFile().exists()) {
			ok = file.getParentFile().mkdirs();
		}

		InputStream in = null;
		if (ok) {
			try {
				URL urlObj = new URL(url);
				in = urlObj.openStream();
				FileOutputStream out = new FileOutputStream(file);
				Streams.copy(in, out, true);
			} finally {
				StreamUtil.closeQuiet(in);
			}
		}
	}

	/**
	 * 读取一个文本内容
	 * 默认使用UTF-8编码
	 * @param url
	 * @return
	 */
	public static String asStringQuiet(String url) {
		return asStringQuiet(url, "UTF-8");
	}

	/**
	 * 读取一个文本内容
	 * @param url
	 * @param pEncoding 字符编码
	 * @return
	 */
	public static String asStringQuiet(String url, String pEncoding) {
		InputStream in = null;
		try {
			URL urlObj = new URL(url);
			in = urlObj.openStream();
			return Streams.asString(in, pEncoding);
		} catch (Exception ex) {
			LoggerFactory.getLogger(URLResource.class).error(
					"read " + url + " occur error:", ex);
		} finally {
			StreamUtil.closeQuiet(in);
		}

		return "";
	}
	
	/**
	 * 对URL的&号转为&
	 * @param url
	 * @return
	 */
	public static String escapeXml(String url)
	{
		if(url==null || url.length()<1)
		{
			return url;
		}
		
		int index = url.indexOf('&');
		if(index<0)
		{
			return url;
		}
		
		StringBuilder sb = new StringBuilder(url);
		int offset = 0;//因为escape导致的偏移量
		while(index!=-1)
		{
			//判断后面是否有amp;
			if(index+4>url.length()-1 || url.charAt(index+1)!='a'|| url.charAt(index+2)!='m'
					|| url.charAt(index+3)!='p'|| url.charAt(index+4)!=';')
			{
				sb.insert(index+1+offset, "amp;");
				offset += 4;
			}
			index = url.indexOf('&', index+1);
		}
		return sb.toString();
	}
	
	/**
	 * 对URL地址编码
	 * 
	 * @param url
	 * @return
	 */
	public String encodeUrl(String url) {
		try {
			url = URLEncoder.encode(url, "utf-8");
		} catch (Exception ex) {
			LoggerFactory.getLogger(URLResource.class).error(
					"encodeUrl " + url + " occur error:", ex);
		}
		return url;
	}

	/**
	 * 对URL地址解码
	 * 
	 * @param url
	 * @return
	 */
	public String decodeUrl(String url) {
		try {
			url = URLDecoder.decode(url, "utf-8");
		} catch (Exception ex) {
			LoggerFactory.getLogger(URLResource.class).error(
					"decodeUrl " + url + " occur error:", ex);
		}
		return url;
	}
	
	/**
	 * 生成调用播放器的playUrl
	 * 
	 * @param args
	 * @return
	 */
	public static String generatePlayerUrl(String... args) {
		StringBuffer sb = new StringBuffer();
		int i = 0;
		for (String arg : args) {
			i++;
			sb.append(arg);
			if (i != args.length) {
				sb.append(",");
			}
		}
		return sb.toString();
	}

}