反射机制-----------通过它获取类中所有东西 出了注释

package demo4;

import java.io.Serializable;

import javax.annotation.Resource;

public  class UserInfo  implements Serializable,Runnable{
    private static final long serialVersionUID = 1L;
    private  String name="张三";
    private int age;
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
     
    @Resource
    public int getAge() {
        return age;
    }
    public void setAge(int age) {
        this.age = age;
    }
    public String say(String text){
        return "你好，我叫小张！"+text;
    }
    @Override
    public void run() {
    }
    public UserInfo(String name, int age) {
        System.out.println("带参构造已执行");
        this.name = name;
        this.age = age;
    }
    public UserInfo() {
    }
}

package demo4;

import java.lang.annotation.Annotation;
import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.lang.reflect.TypeVariable;

import org.junit.After;
import org.junit.Before;
import org.junit.Test;

public class MyTest {
	public static void main(String[] args) throws Exception {
		 //No.1
        Class forName = Class.forName("demo4.UserInfo");
		//        //No.2
		//        Class clazz=UserInfo.class;
		//        //No.3
		//        Class class1 = new UserInfo().getClass();
         getPackageAndClassName(forName);
         System.out.println("-----------------------------------");
         getClassFields(forName);
         System.out.println("-----------------------------------");
         getSuperClassAndInterface(forName);
         System.out.println("-----------------------------------");
         getClassMethod(forName);
         System.out.println("-----------------------------------");
         getClassConstructor(forName);
         System.out.println("-----------------------------------");
         getClassAnnotion(forName);
	}
	
	//包名和类名同时获取
	public static void getPackageAndClassName(Class clazz){
		    Package pack = clazz.getPackage();
		    System.out.println("包名为:"+pack.getName());
		    System.out.println("类的全名为:"+clazz.getName());
		    System.out.println("类名:"+clazz.getSimpleName());
	}
	//获取类中的字段
	public static void getClassFields(Class clazz) throws Exception{
		   //1、getDeclaredFields() 只能获取当前类的字段
		            Field[] declaredFields = clazz.getDeclaredFields();
		            //不知道类名的情况下也可以创建类的对象
		            Object obj = clazz.newInstance();
		            for (Field field : declaredFields) {
		            	  field.setAccessible(true);
						  System.out.println(field.getName()); 
						  //取出字段保存的值
						  System.out.println(field.get(obj));
					}
		            Field field = clazz.getDeclaredField("age");
		            field.setAccessible(true);
		            //给字段赋值
		            field.set(obj, 12);
		           System.out.println("赋值成功！值为:"+ field.get(obj));
		           //获取age字段的数据类型
		           Class<?> type = field.getType();
		           System.out.println("age字段的数据类型是:"+type.getName());
		           //获取访问修饰符
		           int code = field.getModifiers();
		           System.out.println("该字段的访问修饰符是:"+Modifier.toString(code));
	  }
	    //3:获取类的父类以及实现的接口
		public static void getSuperClassAndInterface(Class clazz){
			    System.out.println("该类的父类是:"+clazz.getSuperclass().getName());
			    System.out.println("该类实现的接口有:");
			    Class[] clazzs = clazz.getInterfaces();
			    for (Class class1 : clazzs) {
					System.out.println("接口名称:"+class1.getName());
				}
		}
	    //4:获取类中的方法
		public static void getClassMethod(Class clazz) throws Exception{
			   //可以获取从父类继承过来的方法
			    Method[] methods = clazz.getMethods();
			    System.out.println(methods.length);
			    for (Method method : methods) {
					System.out.println("类和父类的方法有:"+method.getName());
				}
			    System.out.println("--------------------------------------------------------");
			    //获取当前类的方法
			    Method[] declaredMethods = clazz.getDeclaredMethods();
			    for (Method method : declaredMethods) {
					   System.out.println("该类的方法有:"+method.getName());
				}
			    //获取单个方法
			    Method method = clazz.getDeclaredMethod("say",String.class);
			    //获取方法的返回值
			    Class  clazzs = method.getReturnType();
			    System.out.println("该方法的返回值是"+clazzs.getName());
			    //获取方法的形参类型
			    Class[] params = method.getParameterTypes();
			    for (Class class1 : params) {
					System.out.println("形参有:"+class1.getName());
				}
			    //不知道类名的情况下也可以创建类的对象
	            Object obj = clazz.newInstance();
	            //invoke让method对象执行
			    Object obj1= method.invoke(obj, "我是狗");
			    System.out.println("方法执行后的结果是:"+obj1);
		}
		
		//5:获取构造
		public static void getClassConstructor(Class clazz) throws Exception{
			//获取所有构造器
			  Constructor[] constructors = clazz.getConstructors();
			  for (Constructor constructor : constructors) {
				    System.out.println(constructor.getName());
			  }
			  //获取单个构造器
			  Constructor constructor = clazz.getConstructor(String.class,int.class);
			  //执行构造器,返回类的实例
			  Object obj = constructor.newInstance("呵呵",12);
		}
	   //6：获取注解
		 public static void getClassAnnotion(Class clazz) throws Exception{
			       Method method = clazz.getDeclaredMethod("getAge");
			       Annotation[] annotations = method.getAnnotations();
			       for (Annotation annotation : annotations) {
					  System.out.println("该方法的注解有："+annotation.toString());
				}
		 }
}