loading a class from out of classpath by using Java Reflection

问题

I want to load class from that is not in class path. is there any way that I load class by file path without being in classpath ? for example

ClassLoader.load("c:\MyClass.class");

回答1:

Example taken from here:

// Create a File object on the root of the directory containing the class file  
File file = new File("c:\\myclasses\\");

try {
    // Convert File to a URL
    URL url = file.toURL();          // file:/c:/myclasses/
    URL[] urls = new URL[]{url};

    // Create a new class loader with the directory
    ClassLoader cl = new URLClassLoader(urls);

    // Load in the class; MyClass.class should be located in
    // the directory file:/c:/myclasses/com/mycompany
    Class cls = cl.loadClass("com.mycompany.MyClass");
} catch (MalformedURLException e) {
} catch (ClassNotFoundException e) {
}

回答2:

Load your class content into a byte array and use ClassLoader.html#defineClass(java.lang.String, byte[], int, int) manually.

来源：https://stackoverflow.com/questions/5926144/loading-a-class-from-out-of-classpath-by-using-java-reflection