JAVA 在包里搜索所有的类

今天突然想到可不可以动态的去加载添加的类，这样可以省去以后添加类时候修改的麻烦。借鉴前人的 

部分经验得到如下代码：

import java.io.File;import java.io.FileInputStream;import java.util.ArrayList;import java.util.List;import java.util.jar.JarEntry;import java.util.jar.JarInputStream;public class FindPackageClass {public static void main(String[] args) {// String ss="cn.yyzx.test.TestC";// try {// Thread a=(Thread) Class.forName(ss).newInstance();// a.start();// } catch (Exception e) {// e.printStackTrace();// }List<String> cls = getClassInPackage("cn.yyzx.msgsend");for (String s : cls) {System.out.println(s);}}public static List<String> getClassInPackage(String pkgName) {List<String> ret = new ArrayList<String>();String rPath = pkgName.replace('.', '/') + "/";try {for (File classPath : CLASS_PATH_ARRAY) {if (!classPath.exists())continue;if (classPath.isDirectory()) {File dir = new File(classPath, rPath);if (!dir.exists())continue;for (File file : dir.listFiles()) {if (file.isFile()) {String clsName = file.getName();clsName = pkgName+ "."+ clsName.substring(0, clsName.length() - 6);ret.add(clsName);}}} else {FileInputStream fis = new FileInputStream(classPath);JarInputStream jis = new JarInputStream(fis, false);JarEntry e = null;while ((e = jis.getNextJarEntry()) != null) {String eName = e.getName();if (eName.startsWith(rPath) && !eName.endsWith("/")) {ret.add(eName.replace('/', '.').substring(0,eName.length() - 6));}jis.closeEntry();}jis.close();}}} catch (Exception e) {throw new RuntimeException(e);}return ret;}private static String[] CLASS_PATH_PROP = { "java.class.path","java.ext.dirs", "sun.boot.class.path" };private static List<File> CLASS_PATH_ARRAY = getClassPath();private static List<File> getClassPath() {List<File> ret = new ArrayList<File>();String delim = ":";if (System.getProperty("os.name").indexOf("Windows") != -1)delim = ";";System.out.println(System.getProperty("os.name"));for (String pro : CLASS_PATH_PROP) {String[] pathes = System.getProperty(pro).split(delim);for (String path : pathes) {System.out.println(path);ret.add(new File(path));}}return ret;}}

用JDK测试没问题，但到TOMCAT上却无法加载项目的类路径。代码要做修改，先做以上备份。

问题出在 System.getProperty("java.class.path")无法获得项目路径

最后为了简化起见，在web.xml中配置项目路径 然后不搜索系统类

//servlet

public void init(ServletConfig config) throws ServletException {String path = config.getInitParameter("cpath");try {List<String> channel = FindPackageClass.getClassInPackage("cn.yyzx.msgsend", path);for (String ss : channel) {Runnable nc = (Runnable) Class.forName(ss).newInstance();new Thread(nc).start();}} catch (ClassNotFoundException e) {e.printStackTrace();} catch (InstantiationException e) {e.printStackTrace();} catch (IllegalAccessException e) {e.printStackTrace();}this.init();}

public class FindPackageClass {public static void main(String[] args) {List<String> cls = getClassInPackage("cn.yyzx.msgsend", "");for (String s : cls) {System.out.println(s);}}public static List<String> getClassInPackage(String pkgName, String path) {List<String> ret = new ArrayList<String>();String rPath = pkgName.replace('.', '/') + "/";try {File classPath = new File(path);if (classPath.isDirectory()) {File dir = new File(classPath, rPath);for (File file : dir.listFiles()) {if (file.isFile()) {String clsName = file.getName();clsName = pkgName + "." + clsName.substring(0, clsName.length() - 6);ret.add(clsName);}}} else {FileInputStream fis = new FileInputStream(classPath);JarInputStream jis = new JarInputStream(fis, false);JarEntry e = null;while ((e = jis.getNextJarEntry()) != null) {String eName = e.getName();if (eName.startsWith(rPath) && !eName.endsWith("/")) {ret.add(eName.replace('/', '.').substring(0,eName.length() - 6));}jis.closeEntry();}jis.close();}} catch (Exception e) {throw new RuntimeException(e);}return ret;}}

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