JAVA 在包里搜索所有的类

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：

package cn.yyzx.util;

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();
}

package cn.yyzx.util;

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) {
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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