Method.invoke()返回对象的问题 - 黑马程序员技术交流社区

package test;
import java.beans.BeanInfo;
import java.beans.IntrospectionException;
import java.beans.Introspector;
import java.beans.PropertyDescriptor;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
public class Test6 {
/**
* @param args
* @throws IntrospectionException
* @throws InvocationTargetException
* @throws IllegalAccessException
* @throws IllegalArgumentException
*/
public static void main(String[] args) throws IntrospectionException,
IllegalArgumentException, IllegalAccessException,
InvocationTargetException {
Person p = new Person(20, "zhang");
System.out.println("改变前：" + p);
BeanInfo beanInfo = Introspector.getBeanInfo(p.getClass());
PropertyDescriptor[] pds = beanInfo.getPropertyDescriptors();
Object result = new Object();
for (PropertyDescriptor pd : pds) {
//System.out.println("pd.getName()="+pd.getName());//这里的pd.getName返回的是属性名字。age，name
if (pd.getName().equals("age")) {
//1
Method methodSetAge = pd.getWriteMethod();//这里你是获得的写方法setAge。
result = methodSetAge.invoke(p, 25);//还要注意你的setAge方法是没有返回值的。所以result=null
//2
Method methodGet=pd.getReadMethod();
result= methodGet.invoke(p);//这才是读方法。但要注意，读方法是没有参数的。
//提示，你的result的值是你的Person的属性值。而不是Person对象。你怎么把它转成Person
System.out.println("result="+result);
System.out.println("改变后：" + p);
}
}
}
}
class Person {
int age = 3;
String name = "zzz";
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Person(int age, String name) {
this.age = age;
this.name = name;
}
@Override
public String toString() {
return "Person [age=" + age + ", name=" + name + "]";
}
}

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