com.xiongyingqi.util.ClassLookupHelper Maven / Gradle / Ivy
package com.xiongyingqi.util;
import java.io.File;
import java.io.FileFilter;
import java.io.IOException;
import java.net.JarURLConnection;
import java.net.URL;
import java.net.URLClassLoader;
import java.util.*;
import java.util.jar.JarEntry;
import java.util.jar.JarFile;
/**
* Created by xiongyingqi on 14-3-5.
*/
public class ClassLookupHelper {
/**
* Class File 过滤器
*/
public static interface ClassFileFilter {
/**
* 过滤磁盘文件
*/
public boolean accept(String klassName, File file, ClassLoader loader);
/**
* 过滤 Jar 包中的文件
*/
public boolean accept(String klassName, JarFile jar, JarEntry entry, ClassLoader loader);
}
/**
* 从所有的 classpath 下面搜索指定的 Class
*/
public static Collection> getClasses(ClassFileFilter filter) {
Set loaders = new LinkedHashSet(8);
loaders.addAll(getClassLoaders(Thread.currentThread().getContextClassLoader()));
loaders.addAll(getClassLoaders(ClassLookupHelper.class.getClassLoader()));
Set> klasses = new LinkedHashSet>();
for (URLClassLoader cl : loaders) {
for (URL url : cl.getURLs()) {
String file = url.getFile();
if (file.endsWith(".jar") || file.endsWith(".zip")) {
lookupClassesInJar(null, url, true, cl, filter, klasses);
} else {
lookupClassesInFileSystem(null, new File(file), true, cl, filter, klasses);
}
}
}
return klasses;
}
// 根据 baseClassLoader 找到所有的祖先 URLClassLoader (包括自己)
private static Collection getClassLoaders(ClassLoader baseClassLoader) {
Collection loaders = new ArrayList(8);
ClassLoader loader = baseClassLoader;
while (loader != null) {
if ("sun.misc.Launcher$ExtClassLoader".equals(loader.getClass().getName())) {
break;
}
if (loader instanceof URLClassLoader) {
loaders.add((URLClassLoader) loader);
}
loader = loader.getParent();
}
return loaders;
}
/**
* 从指定 package 中获取所有的 Class
*
* @param pkg 包
* @param recursive 是否递归查找
* @param filter class 过滤器
* @return 所有找到的 Class
*/
public static Set> getClasses(Package pkg, boolean recursive, ClassFileFilter filter) {
return getClasses(pkg.getName(), recursive, filter);
}
/**
* 从指定 package 中获取所有的 Class
*
* @param packageName 包名
* @param recursive 是否递归查找
* @param filter class 过滤器
* @return 所有找到的 Class
*/
public static Set> getClasses(String packageName, boolean recursive, ClassFileFilter filter) {
if (packageName == null || packageName.length() == 0) {
throw new IllegalArgumentException("packageName is empty.");
}
ClassLoader loader = Thread.currentThread().getContextClassLoader();
String packageDirName = packageName.replace('.', '/');
Collection urls;
try {
Enumeration dirs = loader.getResources(packageDirName);
urls = Collections.list(dirs);
} catch (IOException e) {
throw new RuntimeException(e);
}
Set> klasses = new LinkedHashSet>();
for (URL url : urls) {
String protocol = url.getProtocol();
if ("file".equals(protocol)) {
lookupClassesInFileSystem(packageName, new File(url.getFile()), recursive, loader, filter, klasses);
} else if ("jar".equals(protocol)) {
lookupClassesInJar(packageName, url, recursive, loader, filter, klasses);
}
}
return klasses;
}
/**
* 以文件的形式来获取包下的所有 Class
*
* @param packageName JAVA包名
* @param packagePath 包所在的文件目录
* @param recursive 是否递归查找
* @param loader 负责该包的 ClassLoader
* @param filter class 过滤器
* @param klasses 返回找到的 class
*/
private static void lookupClassesInFileSystem(String packageName, File packagePath, final boolean recursive, ClassLoader loader, ClassFileFilter filter, Set> klasses) {
if (!packagePath.exists() || !packagePath.isDirectory()) {
return;
}
File[] dirfiles = packagePath.listFiles(new FileFilter() {
public boolean accept(File file) {
return (recursive && file.isDirectory()) || (file.getName().endsWith(".class"));
}
});
String packageNamePrefix = "";
if (packageName != null && packageName.length() > 0) {
packageNamePrefix = packageName + '.';
}
for (File file : dirfiles) {
if (file.isDirectory()) {
lookupClassesInFileSystem(packageNamePrefix + file.getName(), file, recursive, loader, filter, klasses);
} else {
// 去掉后面的 .class 只留下类名
String klassName = packageNamePrefix + file.getName().substring(0, file.getName().length() - 6);
try {
if (filter == null || filter.accept(klassName, file, loader)) {
Class klass = loader.loadClass(klassName);
klasses.add(klass);
}
} catch (Throwable e) {
}
}
}
}
/**
* 以在 Jar 包中获取指定包下的所有 Class
*
* @param packageName JAVA包名
* @param jarUrl Jar 包文件对应的 URL
* @param recursive 是否递归查找
* @param loader 负责该包的 ClassLoader
* @param filter class 过滤器
* @param klasses 返回找到的 class
*/
private static void lookupClassesInJar(String packageName, URL jarUrl, boolean recursive, ClassLoader loader, ClassFileFilter filter, Set> klasses) {
String packageDirName = "";
if (packageName != null && packageName.length() > 0) {
packageDirName = packageName.replace('.', '/') + '/';
}
JarFile jar = null;
try {
if ("jar".equals(jarUrl.getProtocol())) {
jar = ((JarURLConnection) jarUrl.openConnection()).getJarFile();
} else {
jar = new JarFile(jarUrl.getFile());
}
Enumeration entries = jar.entries();
while (entries.hasMoreElements()) {
// 获取jar里的一个实体 可以是目录和一些jar包里的其他文件 如META-INF等文件
JarEntry entry = entries.nextElement();
if (entry.isDirectory()) {
continue;
}
String name = entry.getName();
if (name.charAt(0) == '/') {
name = name.substring(1);
}
if (name.startsWith(packageDirName) && name.endsWith(".class")) {
if (name.lastIndexOf('/') > packageDirName.length()) {
// 在子包内
if (!recursive) continue;
}
// 去掉后面的 .class 只留下类名
String klassName = name.substring(0, name.length() - 6);
klassName = klassName.replace('/', '.');
try {
if (filter == null || filter.accept(klassName, jar, entry, loader)) {
Class klass = loader.loadClass(klassName);
klasses.add(klass);
}
} catch (Throwable e) {
}
}
}
} catch (IOException e) {
} finally {
}
}
public static void main(String[] args){
Collection> classes = getClasses(new ClassFileFilter() {
@Override
public boolean accept(String klassName, File file, ClassLoader loader) {
return true;
}
@Override
public boolean accept(String klassName, JarFile jar, JarEntry entry, ClassLoader loader) {
return true;
}
});
for (Class aClass : classes) {
System.out.println(aClass);
}
}
}
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