PackageClassUtil

/**
 * Copyright (c) 2009-2010 by Glodon
 * All rights reserved.
 */
package gboat2.base.bridge.util;

import gboat2.base.bridge.exception.DefaultGboatNestedException;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.net.URL;
import java.util.ArrayList;
import java.util.List;
import java.util.zip.ZipEntry;
import java.util.zip.ZipInputStream;

import org.apache.commons.io.IOUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;


/**
 * 包，类操作的辅助类
 *
 * @author lysming
 * @since 1.0
 */
public abstract class PackageClassUtil {

    private static final Logger logger = LoggerFactory.getLogger(PackageClassUtil.class);

    /**
     * 获取包中的所有 Java 类
     * @param pkgname 包名，如：gboat2.base.bridge.util
     * @return 包中所有 class
     */
    public static List<Class<?>> getClasses(String pkgname) {
        return getClasses(pkgname, null);
    }

	/**
	 * 获取包中的所有 Java 类
	 *
	 * @param pkgname 包名
	 * @param classLoader 类加载器
	 * @return 返回包中所有 class
	 */
	public static List<Class<?>> getClasses(String pkgname, ClassLoader classLoader) {
		ArrayList<Class<?>> classes = new ArrayList<Class<?>>();

        ClassLoader cld = Thread.currentThread().getContextClassLoader();
        if (cld == null)
            throw new DefaultGboatNestedException("Can't get class loader.");

        String path = pkgname.replace('.', '/');
        URL resource = cld.getResource(path);
        if (resource == null)
            throw new DefaultGboatNestedException("No resource for " + path);

        File directory = new File(resource.getFile());
        String dirPath = directory.getAbsolutePath();
        logger.debug("包 [] 对应的物理路径为：{}", pkgname, dirPath);
		if (directory.exists()) {
			// Get the list of the files contained in the package
			String[] filenames = directory.list();
			String filename = null;
			try {
    			for (int i = 0; i < filenames.length; i++) {
    			    filename = filenames[i];
    				// we are only interested in .class files
    				if (filename.endsWith(".class")) {
    					// removes the .class extension
    					classes.add(Class.forName(pkgname + '.' + filename.substring(0, filename.length() - 6)));
    				}
    			}
			}catch (ClassNotFoundException e) {
			    throw new DefaultGboatNestedException(filename + " does not exist in the package [" + pkgname + "]");
            }
		} else if (dirPath.indexOf(".jar!") != -1) { // 从jar包中读取
			String zipFileName = dirPath.substring(dirPath.indexOf("file") + 6, dirPath.indexOf("!"));
			String prefixPath = dirPath.substring(dirPath.indexOf("!") + 2).replaceAll("\\\\", "/");
			ZipInputStream in = null;
			String name = null;
			try {
				in = new ZipInputStream(new FileInputStream(zipFileName));
				ZipEntry entry = null;
				while ((entry = in.getNextEntry()) != null) {
					if (!entry.isDirectory()) {
						name = entry.getName();
						if (name.startsWith(prefixPath) && name.endsWith(".class")) {
							classes.add(Class.forName(name.substring(0, name.indexOf(".class")).replaceAll("/", ".")));
						}
					}
				}

			} catch (FileNotFoundException e) {
				throw new DefaultGboatNestedException(pkgname + " --> the jar file [" + zipFileName + "] can't find");
			}catch (IOException e) {
				throw new DefaultGboatNestedException(pkgname + " --> the jar file [" + zipFileName + "] can't read");
			} catch (ClassNotFoundException e) {
			    throw new DefaultGboatNestedException(name + " does not exist in the jar file [" + zipFileName + "]");
            } finally {
			    IOUtils.closeQuietly(in); //关闭流
			}
		} else {
			throw new DefaultGboatNestedException(pkgname + " does not appear to be a valid package");
		}
		return classes;
	}

	/** 获取 Java 类所在目录的磁盘物理路径
	 * @param cls Java 类
	 * @return Java 类所在目录的磁盘物理路径，如果传入的 Java 类是在 jar 或 war 包中，则返回对应的 jar 或 war 包所在目录的物理路径
	 */
	public static String getRealPath(Class<?> cls) {
		// 检查用户传入的参数是否为空
		if (cls == null)
			throw new java.lang.IllegalArgumentException("参数不能为空！");

		ClassLoader loader = cls.getClassLoader();
		// 获得类的全名，包括包名
		String clsName = cls.getName() + ".class";
		// 获得传入参数所在的包
		Package pack = cls.getPackage();
		String path = "";
		StringBuilder pathSB = new StringBuilder();
		// 如果不是匿名包，将包名转化为路径
		if (pack != null) {
			String packName = pack.getName();
			// 此处简单判定是否是Java基础类库，防止用户传入JDK内置的类库
			if (packName.startsWith("java.") || packName.startsWith("javax."))
				throw new java.lang.IllegalArgumentException("不要传送系统类！");

			// 在类的名称中，去掉包名的部分，获得类的文件名
			clsName = clsName.substring(packName.length() + 1);
			// 判定包名是否是简单包名，如果是，则直接将包名转换为路径，
			if (packName.indexOf(".") < 0)
				//path = packName + "/";
				pathSB.append(packName + "/");
			else { // 否则按照包名的组成部分，将包名转换为路径
				int start = 0, end = 0;
				end = packName.indexOf(".");
				while (end != -1) {
					//path = path + packName.substring(start, end) + "/";
					pathSB.append(packName.substring(start, end) + "/");
					start = end + 1;
					end = packName.indexOf(".", start);
				}
				//path = path + packName.substring(start) + "/";
				pathSB.append(packName.substring(start) + "/");
			}
		}
		path = pathSB.toString();
		// 调用ClassLoader的getResource方法，传入包含路径信息的类文件名
		java.net.URL url = loader.getResource(path + clsName);
		// 从URL对象中获取路径信息
		String realPath = url.getPath();
		// 去掉路径信息中的协议名"file:"
		int pos = realPath.indexOf("file:");
		if (pos > -1)
			realPath = realPath.substring(pos + 5);
		// 去掉路径信息最后包含类文件信息的部分，得到类所在的路径
		pos = realPath.indexOf(path + clsName);
		realPath = realPath.substring(0, pos - 1);
		// 如果类文件被打包到JAR等文件中时，去掉对应的JAR等打包文件名
		if (realPath.endsWith("!"))
			realPath = realPath.substring(0, realPath.lastIndexOf("/"));
		/*------------------------------------------------------------
		 ClassLoader的getResource方法使用了utf-8对路径信息进行了编码，当路径
		  中存在中文和空格时，他会对这些字符进行转换，这样，得到的往往不是我们想要
		  的真实路径，在此，调用了URLDecoder的decode方法进行解码，以便得到原始的
		  中文及空格路径
		-------------------------------------------------------------*/
		try {
			realPath = java.net.URLDecoder.decode(realPath, "utf-8");
		} catch (Exception e) {
			throw new RuntimeException(e);
		}
		return realPath;
	}
}