java通过反射调用方法

java通过反射调用方法

java

反射

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;

/**

*

* @author outofmemory.cn

*/

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;

}

}

}

上面代码将输出：

getBrand: DELL

getHarddiskSize_GB: 300

isAntiVirusInstalled: true

getType: Laptop