使用参数类型调用方法

import java.lang.reflect.Method;

public class MethodTroubleToo {
    public void ping() {
        System.out.format("PONG!%n");
    }

    public static void main(String... args) {
        try {
            MethodTroubleToo mtt = new MethodTroubleToo();
            Method m = MethodTroubleToo.class.getMethod("ping");

            switch (Integer.parseInt(args[0])) {
            case 0:
                m.invoke(mtt); // works
                break;
            case 1:
                m.invoke(mtt, null); // works (expect compiler warning)
                break;
            case 2:
                Object arg2 = null;
                m.invoke(mtt, arg2); // IllegalArgumentException
                break;
            case 3:
                m.invoke(mtt, new Object[0]); // works
                break;
            case 4:
                Object arg4 = new Object[0];
                m.invoke(mtt, arg4); // IllegalArgumentException
                break;
            default:
                System.out.format("Test not found%n");
            }

            // production code should handle these exceptions more gracefully
        } catch (Exception x) {
            x.printStackTrace();
        }
    }
}