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Java通过反射调用方法

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下面代码演示如何通过反射调用方法。

首先通过Class实例的getDeclaredMethods()获得所有方法的定义,然后通过Method的invoke方法触发方法调用,invoke方法的第一个参数是方法所属对象,第二个参数是方法调用的参数列表。

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;

public class Main {

    /**
     * Invokes the methods of an object using the Reflection api.
     */
    public void invokeMethodsUsingReflection() {

        //Obtain the Class instance
        Class computerClass = Computer.class;

        //Get the methods
        Method[] methods = computerClass.getDeclaredMethods();

        //Create the object that we want to invoke the methods on
        Computer computer = new Computer();

        //Loop through the methods and invoke them
        for (Method method : methods) {
            Object result;
            try {
                //Call the method. Since none of them takes arguments we just
                //pass an empty array as second parameter.
                result = method.invoke(computer, new Object[0]);
            } catch (IllegalArgumentException ex) {
                ex.printStackTrace();
                return;
            } catch (InvocationTargetException ex) {
                ex.printStackTrace();
                return;
            } catch (IllegalAccessException ex) {
                ex.printStackTrace();
                return;
            }
            System.out.println(method.getName() + ": " + result);
        }
    }

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        new Main().invokeMethodsUsingReflection();
    }

    class Computer {

        private String brand = "DELL";
        private String type = "Laptop";
        private int harddiskSize_GB = 300;
        private boolean AntiVirusInstalled = true;

        public String getBrand() {
            return brand;
        }

        public String getType() {
            return type;
        }

        public int getHarddiskSize_GB() {
            return harddiskSize_GB;
        }

        public boolean isAntiVirusInstalled() {
            return AntiVirusInstalled;
        }
    }
}

标签:java

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