java-反射: How to Override private static abstract inner class method?

Question

我有以下类(class):

class MyClass{

    private static final int VERSION_VALUE = 8;

    private static final String VERSION_KEY = "versionName";

    public boolean myPublicMethod(String str) {
        try { 
            return myPrivateMethod(str, VERSION_KEY, VERSION_VALUE,
                    new MyInnerClass() {

                    @Override
            public InputStream loadResource(String name) {
                            //do something important
                        }
                    });
        }
        catch (Exception e) {           
        }
        return false;
    }


private boolean myPrivateMethod(String str, String key, int version,
            ResourceLoader resourceLoader) throws Exception
    {
       //do something 
    }

    private static abstract class MyInnerClass {

        public abstract InputStream loadResource(String name);

    }
}

我想为 myPrivateMethod 编写单元测试，我需要为其传递 resourceLoader 对象并覆盖它的 loadResource 方法。

这是我的测试方法:

@Test
public void testMyPrivateMethod() throws Exception {
    Class<?> cls = Class.forName("my.pack.MyClass$MyInnerClass");
    Method method = cls.getDeclaredMethod("loadResource", String.class);
    //create inner class instance and override method
    Whitebox.invokeMethod(myClassObject, "testValue1", "testValue2", "name1", 10, innerClassObject);
}

请注意，我无法更改代码。

Answer 1

嗯，你可以使用Javassist ...

参见this question 。我还没有尝试过这个，但是当你想要覆盖时你可以调用这个方法:

public <T extends Object> T getOverride(Class<T> cls, MethodHandler handler) {
    ProxyFactory factory = new ProxyFactory();
    factory.setSuperclass(cls);
    factory.setFilter(
            new MethodFilter() {
                @Override
                public boolean isHandled(Method method) {
                    return Modifier.isAbstract(method.getModifiers());
                }
            }
        );

    return (T) factory.create(new Class<?>[0], new Object[0], handler);
}