Java使用反射实例化类，得到域的值，调用该类的方法

我不是女神ヾ 2022-05-19 11:04 106阅读 0赞

获得类和实例

我们以汽车类型为例：

public class Car {
    	private  String name = "111";
    	public double salary = 12.0;
    
    	public String getName() {
    		return name;
    	}
    
    	private void setName(String name) {
    		this.name = name;
    	}
    
    	public double getSalary() {
    		return salary;
    	}
    
    	public void setSalary(double salary) {
    		this.salary = salary;
    	}
    
    	@Override
    	public String toString() {
    		return "Car [name=" + name + ", salary=" + salary + "]";
    	}
    	
    	
    	
    }

然后利用反射获得类和他的实例：

public static void main(String[] args)  {
    	try {
    		Class car = Class.forName("Car");
    		Car car2 = (Car) car.newInstance();
    		System.out.println(car);
    		System.out.println(car2);			
    	} catch (Exception e) {
    		// TODO Auto-generated catch block
    		e.printStackTrace();
    	}
    }

输出为：

class Car
    Car [name=111, salary=12.0]

然后获得遍历获得他的所有域和值：

public static void main(String[] args)  {
    	try {
    		Class car = Class.forName("Car");		
    		Field[] f =  car.getDeclaredFields();
    			for(Field fie : f) {
    				fie.setAccessible(true);
    				System.out.println(fie.toString()+" : "+fie.get(car.newInstance()));
    			}		
    	} catch (Exception e) {
    		// TODO Auto-generated catch block
    		e.printStackTrace();
    	}
    }

输出为：

private java.lang.String Car.name : 111
    public double Car.salary : 12.0

接下来我们尝试执行他的私有和公有方法：

public static void main(String[] args)  {
    	try {
    		Class car = Class.forName("Car");
    		Car car2 = (Car) car.newInstance();
    		Method method = car.getDeclaredMethod("setName",String.class);		
    		method.setAccessible(true);
    		//name值改变成5555
    		method.invoke(car2,"5555");
    				
    		Method method2 = car.getDeclaredMethod("getName");		
    		System.out.println(method2.invoke(car2));
    	} catch (Exception e) {
    		// TODO Auto-generated catch block
    		e.printStackTrace();
    	}
    }

输出为：

5555