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：

 1 //public
 2 Constructor getConstructor()
 3 Method getMethod()
 4 Field getField()
 5 //private
 6 Constructor getDeclaredConstructor()
 7 Method getDeclaredMethod()
 8 Field getDeclaredField()
 9 
10 c.setAccessible(true);//暴力反射

反射类的构造函数：

1 public void test(){
2         Class c = Class.forName("javaweb.reflect.Person");
3         Constructor<T> cs = c.getConstructor(String.class);
4         Person p = cs.newInstance("xxx");
5     }

反射类的方法：

1 public void test() throws ClassNotFoundException {
2             Person p = new Person();
3             Class c = Class.forName("javaweb.reflect.Person");
4             Method method = c.getMethod("funName", null);
5             method.invoke(p,null);
6         }

反射类的字段：

 1 package javaweb.reflect;
 2 
 3 import java.lang.reflect.Field;
 4 
 5 public class Reflect {
 6 
 7     /**
 8      * @param args
 9      * @throws ClassNotFoundException 
10      * 反射：加载类，获得类的字节码
11      * @throws SecurityException 
12      * @throws NoSuchFieldException 
13      * @throws IllegalAccessException 
14      * @throws IllegalArgumentException 
15      */
16     public static void main(String[] args) throws ClassNotFoundException, NoSuchFieldException, SecurityException, IllegalArgumentException, IllegalAccessException{
17         Person p = new Person();
18         Class<?> c = Class.forName("javaweb.reflect.Person");
19         Field f = c.getField("name");
20         String name =(String) f.get(p);
21         System.out.println(name);
22         
23         //打印出字段name的类型
24         Class<?> type = f.getType();
25         System.out.println(type);
26     }
27 }