java - Android-在运行时加载外部.jar

我想在运行时加载外部库。

来源如下：

import java.lang.*;
import java.net.*;
import java.io.*;

public class Main {
    public static void main (String args[]) throws Exception {
        System.out.println("Load support library");
        File file = new File("/sdcard/lib/android-support-v4.jar");
        URL url = file.toURI().toURL();
        URL[] urls = {url};
        URLClassLoader cl = new URLClassLoader(urls);
        Class clazz = cl.loadClass("android.support.v4.view.ViewCompat");
    }
}

该库是Google的支持库。
它位于“ /sdcard/lib/android-support-v4.jar”。

我想获取“ android.support.v4.view.ViewCompat”类，但源始终抛出ClassNotFoundException。

最佳答案

JCL class loader framework怎么样。
用法示例：

JarClassLoader jcl = new JarClassLoader();
jcl.add("myjar.jar"); //Load jar file
jcl.add(new URL("http://myserver.com/myjar.jar")); //Load jar from a URL
jcl.add(new FileInputStream("myotherjar.jar")); //Load jar file from stream
jcl.add("myclassfolder/"); //Load class folder
jcl.add("myjarlib/"); //Recursively load all jar files in the folder/sub-folder(s)

JclObjectFactory factory = JclObjectFactory.getInstance();

//Create object of loaded class
Object obj = factory.create(jcl,"mypackage.MyClass");