package Reflect;
public class ReflectPerson {
private String name;
private int age;
public ReflectPerson(String name, int age) {
this.name = name;
this.age = age;
System.out.println("Person param run @ " + this.name + " @ " + this.age);
}
public ReflectPerson() {
System.out.println("Person run");
}
public void show() {
System.out.println(name + " @ " + age);
}
private void method() {
System.out.println("method run");
}
public void paramMethod(String str, int num) {
System.out.println("paramMethod run" + str + " @ " + num);
}
public static void staticMethod() {
System.out.println("static method run");
}
}
package Reflect;
import java.lang.reflect.Field;
public class ReflectDemo3 {
public static void main(String[] args) throws Exception {
getFieldDemo();
}
public static void getFieldDemo() throws Exception {
Class c = Class.forName("Reflect.ReflectPerson");
Field field = null; //c.getField("age"); //只能獲取公有的
field = c.getDeclaredField("age");//只獲取本類，但包含私有
//對私有字段的訪問取消權限檢查，暴力訪問 -> 不推薦
field.setAccessible(true);
Object obj = c.newInstance();
field.set(obj, 90);//將 age 設置為 89
Object o = field.get(obj);
System.out.println(o);
}
}打印結果
Person run
90