【Java__反射】基础复习

实例代码

package sys.test;

import java.lang.reflect.Field;
import java.lang.reflect.Method;

public class Main {
    public static void main(String[] args) throws Exception {
        /**
         * 获取TargetObject类的Class对象并且创建TargetObject类实例
         */
        Class<?> targetClass = Class.forName("sys.test.TargetObject");
        TargetObject targetObject = (TargetObject) targetClass.newInstance();
        /**
         * 获取所有类中所有定义的方法
         */
        Method[] methods = targetClass.getMethods();
        for (Method m1 : methods) {
            // System.out.println(m1.getName());
        }
        /**
         * 获取指定方法并调用
         */
        Method publicMethod = targetClass.getMethod("publicMethod", String.class);
        publicMethod.invoke(targetObject, "you");
        /**
         * 获取指定参数并对参数进行修改
         */
        Field value = targetClass.getDeclaredField("value");
        //为了调用private方法我们取消安全检查
        value.setAccessible(true);
        value.set(targetObject, "zhangshan");
        /**
         * 调用 private 方法
         */
        Method privateMethod = targetClass.getDeclaredMethod("privateMethod");
        //为了调用private方法我们取消安全检查
        privateMethod.setAccessible(true);
        privateMethod.invoke(targetObject);
    }
}

package sys.test;

public class TargetObject {
    private String value;

    public TargetObject() {
        value = "JavaGuide";
    }

    public void publicMethod(String s) {
        System.out.println("I love " + s);
    }

    private void privateMethod() {
        System.out.println("value is " + value);
    }
}