关于反射机制的一些示例

package com.ntqingniao.reflect;

public class Client2 {
public static void main(String[] args) {
Demo demo = new Demo();
// 根据对象获取完整的包名和类名
System.out.println(demo.getClass().getName());
}
}

class Demo2 {

}

package com.ntqingniao.reflect;

public class Client3 {
public static void main(String[] args) throws ClassNotFoundException {

// Class类是所有对象的元数据的类对象
Class<?> demo1 = null;
Class<?> demo2 = null;
Class<?> demo3 = null;

demo1 = Class.forName("com.ntqingniao.reflect.Demo3");
demo2 = new Demo3().getClass();
demo3 = Demo3.class;

System.out.println(demo1.getName());
System.out.println(demo2.getName());
System.out.println(demo3.getName());
}
}

class Demo3 {

}

package com.ntqingniao.reflect;

public class Client4 {
public static void main(String[] args) throws ClassNotFoundException, InstantiationException, IllegalAccessException {
Class<?> demo = null;
// 通过类全名创建Class对象（类型的工厂）
demo = Class.forName("com.ntqingniao.reflect.Person");
// 调用工厂的newInstance()方法创建对象
Person per = (Person)demo.newInstance();
per.setName("Tom");
System.out.println(per);
}
}

class Person {
private String name;
private int age;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
@Override
public String toString() {
return "Person [" + (name != null ? "name=" + name + ", " : "") + "age=" + age + "]";
}
}

// 获取该类的所有构造器对象
Constructor<?> cons[] = demo.getConstructors();
// 通过构造器对象的newInstance(Object.. params)可变参数方法构建对象
Person per1 = (Person)cons[0].newInstance();
Person per2 = (Person)cons[1].newInstance("Tom", 20);
System.out.println(per1);
System.out.println(per2);

// 获取类的所有接口和直接父类方法
Class<?> inters[] = demo.getInterfaces();
Class<?> supers = demo.getSuperclass();

// 获取类的全部属性
Field[] fields = demo.getDeclaredFields();
for (int i = 0; i < fields.length; i++) {
// 获取权限修饰符
int mo = fields[i].getModifiers();
String priv = Modifier.toString(mo);
// 数据类型
Class<?> type = fields[i].getType();
// 属性变量名
String name = fields[i].getName();
System.out.println(priv + " " + type.getName() + " " + name );
}

Method method = demo.getMethod("getName");
method.invoke(demo.newInstance());

Person p = new Person();
Method method2 = demo.getMethod("getName", String.class);
method2.invoke(p, "Reflect");

p.getName("Reflect");