classlocation.java

用java开发的关于

/**
 * <p>
 * Title:
 * </p>
 * <p>
 * Description:
 * </p>
 * <p>
 * Copyright: Copyright (c) 2004
 * </p>
 * <p>
 * Company:
 * </p>
 * 
 * @author not attributable
 * @version 1.0
 */
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.*;
import java.util.Properties;
import java.util.jar.JarFile;
import java.util.zip.ZipEntry;

public class ClassLocation implements ConstString
{
	/**
	 * 取得指定类所在目录，如果类在一个Jar文件中，则指的是这个Jar文件所在目录
	 * 
	 * @param cls
	 *        指定类
	 * @return 指定类所在目录，如果没有找到该类返回空字符串
	 */
	public static String getClassDir(Class cls)
	{
		try
		{
			URL url = getClassURL(cls);
			if (url == null)
			{
				return EMPTY_STRING;
			}
			String classpath = url.getPath();
			int nl = cls.getName().length() + DOTCLASS.length();
			int pl = classpath.length();
			int i_cut_start = 0;
			int i_cut_end = pl - nl;
			classpath = classpath.substring(i_cut_start, i_cut_end);
			if (url.getProtocol().equalsIgnoreCase(PROTOCOL_JAR))
			{
				pl = i_cut_end - 1;
				classpath = classpath.substring(0, pl); // cut the last slash
				if (classpath.startsWith(PROTOCOL_FILE + COLON))
				{
					i_cut_start = PROTOCOL_FILE.length() + COLON.length();
				}
				i_cut_end = classpath.lastIndexOf(SLASH);
				classpath = classpath.substring(i_cut_start, i_cut_end);
			}
			if (!classpath.endsWith(SLASH))
			{
				classpath += SLASH;
			}
			return URLDecoder.decode(classpath, CSN_UTF_8);
		}
		catch(Exception e)
		{
			// Do nothing
		}
		return EMPTY_STRING;
	}

	/**
	 * 取得指定类所在目录或jar文件
	 * 
	 * @param cls
	 *        指定类
	 * @return 指定类所在目录，如果没有找到该类返回空字符串
	 */
	public static String getClassPath(Class cls)
	{
		try
		{
			URL url = getClassURL(cls);
			if (url == null)
			{
				return EMPTY_STRING;
			}
			String classpath = url.getPath();
			int nl = cls.getName().length() + DOTCLASS.length();
			int pl = classpath.length();
			int i_cut_start = 0;
			int i_cut_end = pl - nl;
			classpath = classpath.substring(i_cut_start, i_cut_end);
			if (classpath.startsWith(PROTOCOL_FILE + COLON))
			{
				i_cut_start = PROTOCOL_FILE.length() + COLON.length();
				classpath = classpath.substring(i_cut_start);
			}
			if (classpath.endsWith(SLASH))
			{
				classpath = classpath.substring(0, classpath.length() - 1);
			}
			return URLDecoder.decode(classpath, CSN_UTF_8);
		}
		catch(Exception e)
		{
			// Do nothing
		}
		return EMPTY_STRING;
	}

	/**
	 * 取得指定类的存取位置URL
	 * 
	 * @param cls
	 *        指定类
	 * @return 指定类所在存取位置URL，如果没有找到该类返回空
	 */
	public static URL getClassURL(Class cls)
	{
		try
		{
			ClassLoader cl = ClassLoader.getSystemClassLoader();
			String classname = cls.getName();
			String findresname = classname.replace('.', '/') + DOTCLASS;
			URL url = cl.getResource(findresname);
			if (url == null)
			{
				int i = classname.lastIndexOf(DOT);
				findresname = classname.substring(i + 1) + DOTCLASS;
				url = cls.newInstance().getClass().getResource(findresname);
			}
			return url;
		}
		catch(Exception e)
		{
			// Do nothing
		}
		return null;
	}

	/**
	 * 取得相对于指定class所在路径的文件的InputStream
	 * 
	 * <pre>
	 *  
	 *   
	 *    
	 *      
	 *      e.g. 
	 *      class = com.company.app.relate
	 *      classpath = /www/WEB-INF/classes/com/company/app/relate.class 
	 *      relatefile = resource/readme.txt find the file 
	 *      path = /www/WEB-INF/classes/resource/readme.txt 
	 *      classpath = /www/WEB-INF/lib/aa.jar![com/company/app/relate.class] 
	 *      relatefile = resource/readme.txt 
	 *      
	 *      find the file path 
	 *      first = /www/WEB-INF/lib/resource/readme.txt 
	 *      find the file path 
	 *      next = /www/WEB-INF/lib/aa.jar![resource/readme.txt]
	 *      
	 *      
	 *     
	 *    
	 *   
	 * </pre>
	 * 
	 * @param PathRelateClass
	 * @param FilePath
	 * @return
	 * @throws IOException
	 */
	public static InputStream getFileInputStream(Class PathRelateClass,
		String RelateFilePath) throws IOException
	{
		InputStream is;
		String s = getClassPath(PathRelateClass);
		if (s.endsWith("!"))
		{
			// cut the jar file
			int i = s.lastIndexOf(SLASH);
			String filesamejardir = s.substring(0, i) + '/' + RelateFilePath;
			if (new File(filesamejardir).exists())
			{
				return new FileInputStream(filesamejardir);
			}
			// is a jar file, cut the "!"
			s = s.substring(0, s.length() - 1);
			JarFile jf = new JarFile(s);
			ZipEntry ze = jf.getEntry(RelateFilePath);
			return jf.getInputStream(ze);
		}
		else
		{
			s = s + '/' + RelateFilePath;
			return new FileInputStream(s);
		}
	}

	public static InputStream getFileInputStream(String relateFilePath)
		throws IOException
	{
		return getFileInputStream(ClassLocation.class, relateFilePath);
	}

	public static Properties loadProperties(String filename) throws IOException
	{
		Properties p = new Properties();
		InputStream is = getFileInputStream(filename);
		p.load(is);
		return p;
	}
}