java reflect反射调用方法invoke

类定义

package Reflect;

public class MyTest {

    public int a;

    public static int b;

    public static final int c = 0;

    private int d;

    public int sum(int a, int b) {

        return a + b;

    }

    public int sub(int a, int b, String c) {
 　　　　System.out.println(c);
        return a - b;

    }

    MyTest() {

    }

    MyTest(int a, int b) {

    }

}

反射调用

package Reflect;

import java.lang.reflect.Constructor;

import java.lang.reflect.Field;

import java.lang.reflect.Method;

import java.lang.reflect.Modifier;

public class Test {

    public static void main(String[] args) {

        // invoke the reflect-method

        try {

            final Class z = Class.forName("Reflect.MyTest");

            final Class[] params = new Class[3];// define the param-type

            params[0] = int.class;

            params[1] = int.class;

            params[2] = String.class;

            // final Method m = z.getDeclaredMethod("sub", params);

            final Method m = z.getMethod("sub", int.class, int.class, String.class);

            // final Method m = z.getDeclaredMethod("sum", int.class, int.class);

            // set in-param

            final Object[] p = new Object[3];

            p[0] = 100;

            p[1] = 50;

            p[2] = "hello word!";

            System.out.println();

            final Integer s = (Integer) m.invoke(z.newInstance(), p);

            // final Integer s = (Integer) m.invoke(z.newInstance(), 3, 5);

            System.out.println("return value==" + s);

        } catch (final Exception e) {

            e.printStackTrace();

        }

    }

}

输出：

hello word!
return value==50