通过指定一个包名获取该包名下所有的类，主要思路是遍历当前jvm依赖的jar包，以及引用的class文件目录，即java.class.path，在java中，我们可以使用System.getProperty获取其值，具体实现为：
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| private List<Class<?>> getClassByPackageName(String packageName) {
List<Class<?>> classes = new ArrayList<>();
String packagePath = packageName.replace(".", "/");
String[] classPathEntries = System.getProperty("java.class.path")
.split(System.getProperty("path.separator"));
for (String classpathEntry : classPathEntries) {
if (classpathEntry.endsWith(".jar")) {
File jar = new File(classpathEntry);
try (FileInputStream fileInputStream = new FileInputStream(jar);
JarInputStream jarInputStream = new JarInputStream(fileInputStream)) {
JarEntry entry;
while ((entry = jarInputStream.getNextJarEntry()) != null) {
String name = entry.getName();
if (name.endsWith(".class")) {
if (name.contains(packagePath) && name.endsWith(".class")) {
String classPath = name.substring(0, entry.getName().length() - 6);
classPath = classPath.replaceAll("[|/]", ".");
classes.add(Class.forName(classPath));
}
}
}
} catch (Exception e) {
throw new RuntimeException(e);
}
} else {
try {
File base = new File(classpathEntry + File.separatorChar + packagePath);
Queue<File> fileQueue = new LinkedList<>();
fileQueue.offer(base);
while (fileQueue.peek() != null) {
File currentFile = fileQueue.poll();
if (currentFile.isDirectory()) {
File[] subFiles = currentFile.listFiles();
if (subFiles != null) {
for (File subFile : subFiles) {
fileQueue.offer(subFile);
}
}
} else if (currentFile.isFile()) {
if (currentFile.getName().endsWith(".class")) {
String className = currentFile.getPath()
.replace(classpathEntry + "/", "")
.replace("/", ".");
className = className.substring(0, className.length() - 6);
classes.add(Class.forName(className));
}
}
}
} catch (Exception e) {
throw new RuntimeException(e);
}
}
}
return classes;
}
|
如果你的项目引用了spring依赖包，那么也可以使用ClassPathScanningCandidateComponentProvider 获取包名下的class。
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| private List<Class<?>> getClassByPackageName(String packageName) {
List<Class<?>> clazzs = new ArrayList<>();
ClassPathScanningCandidateComponentProvider provider =
new ClassPathScanningCandidateComponentProvider(false);
provider.addIncludeFilter((metadataReader, metadataReaderFactory) -> {
String className = metadataReader.getClassMetadata().getClassName();
try {
Class<?> clazz = Class.forName(className);
clazzs.add(clazz);
} catch (ClassNotFoundException e) {
throw new BizCoreException(e.getMessage());
}
return true;
});
provider.findCandidateComponents(packageName);
return clazzs;
}
|
