反射

package javaweb.reflect;

public class Reflect {

    /**
     * @param args
     * @throws ClassNotFoundException 
     * 反射：加载类，获得类的字节码
     */
    public static void main(String[] args) throws ClassNotFoundException {
        //加载类方法1：
        Class c1 = Class.forName("javaweb.reflect.Person");
        //2
        Class c2 = new Person().getClass();
        //3
        Class c3 = Person.class;
    }

}

常用方法：

//public
Constructor getConstructor()
Method getMethod()
Field getField()
//private
Constructor getDeclaredConstructor()
Method getDeclaredMethod()
Field getDeclaredField()

c.setAccessible(true);//暴力反射

 反射类的构造函数：

public void test(){
        Class c = Class.forName("javaweb.reflect.Person");
        Constructor<T> cs = c.getConstructor(String.class);
        Person p = cs.newInstance("xxx");
    }

反射类的方法：

public void test() throws ClassNotFoundException {
            Person p = new Person();
            Class c = Class.forName("javaweb.reflect.Person");
            Method method = c.getMethod("funName", null);
            method.invoke(p,null);
        }

反射类的字段：

package javaweb.reflect;

import java.lang.reflect.Field;

public class Reflect {

    /**
     * @param args
     * @throws ClassNotFoundException 
     * 反射：加载类，获得类的字节码
     * @throws SecurityException 
     * @throws NoSuchFieldException 
     * @throws IllegalAccessException 
     * @throws IllegalArgumentException 
     */
    public static void main(String[] args) throws ClassNotFoundException, NoSuchFieldException, SecurityException, IllegalArgumentException, IllegalAccessException{
        Person p = new Person();
        Class<?> c = Class.forName("javaweb.reflect.Person");
        Field f = c.getField("name");
        String name =(String) f.get(p);
        System.out.println(name);
        
        //打印出字段name的类型
        Class<?> type = f.getType();
        System.out.println(type);
    }
}