我正在寻找一种实用方法,以便给定的类将返回在外部运行该类所需的完整类路径。这意味着类所在的 jar 以及它使用的类的所有 jar(或文件夹)。
更新:有一些工具可以分析 .class 文件以查找依赖项。这不是我要找的。我正在寻找在已加载的类上使用 Java 反射 API 的东西。我会选择分析字节码的东西,如果它递归地进入通过类加载器找到的类
最佳答案
反射(reflection)对于这件事不会有太大帮助。您将需要分析字节码以查找依赖项。
更新:
那好吧。我正在使用我几年前制作的一个库,您可以下载here .
以下代码:
package classdep;
import java.io.InputStream;
import java.net.URL;
import java.util.ArrayList;
import java.util.List;
import org.jedo.classfile.ClassFile;
import org.jedo.classfile.ConstantPool;
public class Main {
public static void main(String[] args) {
try {
ClassLoader cl = Thread.currentThread().getContextClassLoader();
List<String> classes = new ArrayList<String>();
classes.add(args[0].replace('.', '/'));
for (int i = 0; i < classes.size(); ++i) {
String className = classes.get(i);
URL url = cl.getResource(className + ".class");
if (url == null) {
System.out.println("--- class not found " + className);
} else {
System.out.println(url);
ClassFile classFile = new ClassFile();
InputStream in = url.openStream();
try {
classFile.load(in);
} finally {
in.close();
}
ConstantPool cp = classFile.getConstantPool();
for (String name: cp.getClassNames()) {
if (!classes.contains(name)) {
classes.add(name);
}
}
}
}
} catch (Exception e) {
e.printStackTrace();
}
}
}
将为您提供一个类的所有依赖项。当应用于 org.jedo.classfile.ClassFile 时,它会产生以下输出:
file:/D:/projects/casagrande/jedo/build/classes/org/jedo/classfile/ClassFile.class
file:/D:/projects/casagrande/jedo/build/classes/org/jedo/classfile/ConstantPool.class
file:/D:/projects/casagrande/jedo/build/classes/org/jedo/classfile/FieldInfo.class
file:/D:/projects/casagrande/jedo/build/classes/org/jedo/classfile/MethodInfo.class
file:/D:/projects/casagrande/jedo/build/classes/org/jedo/classfile/AttributeInfo.class
jar:file:/C:/Program%20Files/Java/jdk1.6.0_18/jre/lib/rt.jar!/java/io/File.class
jar:file:/C:/Program%20Files/Java/jdk1.6.0_18/jre/lib/rt.jar!/java/io/FileInputStream.class
jar:file:/C:/Program%20Files/Java/jdk1.6.0_18/jre/lib/rt.jar!/java/io/DataInputStream.class
jar:file:/C:/Program%20Files/Java/jdk1.6.0_18/jre/lib/rt.jar!/java/io/StreamCorruptedException.class
jar:file:/C:/Program%20Files/Java/jdk1.6.0_18/jre/lib/rt.jar!/java/io/FileOutputStream.class
jar:file:/C:/Program%20Files/Java/jdk1.6.0_18/jre/lib/rt.jar!/java/io/DataOutputStream.class
jar:file:/C:/Program%20Files/Java/jdk1.6.0_18/jre/lib/rt.jar!/java/lang/StringBuilder.class
jar:file:/C:/Program%20Files/Java/jdk1.6.0_18/jre/lib/rt.jar!/java/lang/StringBuffer.class
jar:file:/C:/Program%20Files/Java/jdk1.6.0_18/jre/lib/rt.jar!/java/lang/Object.class
jar:file:/C:/Program%20Files/Java/jdk1.6.0_18/jre/lib/rt.jar!/java/io/IOException.class
...
后面是很多系统类。您需要过滤掉系统类,并解析其他 url 以提取 .jar 文件(如果它是 jar: url)或目录(如果它是 file: url)。
关于java - 从类中获取完整的类路径,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/3437426/