Java基础技术之反射详解

package cn.yx.zg.反射.demo3;
public class Person {
	private String name;
	private int age;
	public Person() {
		super();
	}
	public Person(String name, int age) {
		super();
		this.name = name;
		this.age = 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=" + name + ", age=" + age + "]";
	}
	public void eat() {
		System.out.println("调用无参方法");
	}
	public void eat(int num) {
		System.out.println("调用有参方法");
	}
}

public static void main(String[] args) throws Exception {
	Class<Person> clazz1 = (Class<Person>) Class.forName("cn.yx.zg.反射.demo3.Person");
	Class clazz2 = Person.class;
	Person p = new Person();
	Class clazz3 = p.getClass();
	System.out.println(clazz1 == clazz2);//true
	System.out.println(clazz2 == clazz3);//true
	//常用的方式
	try {
	   Class npcClazz3 = Class.forName("com.反射机制.demo1.Person");
	  } catch (ClassNotFoundException e) {
	     e.printStackTrace();
	 }
 }

public static void main(String[] args) throws Exception {
        Class clazz = Class.forName("cn.yx.zg.反射.demo3.Person");
        //通过无参构造创建对象
        Person p = (Person) clazz.newInstance();
        System.out.println(p);
        //通过构造方法参数创建对象
        Constructor c = clazz.getConstructor(String.class,int.class);	//获取有参构造
        Person p2 = (Person) c.newInstance("张三",23);						//通过有参构造创建对象
        System.out.println(p2);
    }

public static void main(String[] args) throws Exception {
   Class clazz = Class.forName("cn.yx.zg.反射.demo3.Person");
   Constructor c = clazz.getConstructor(String.class, int.class);    //获取有参构造
   Person p = (Person) c.newInstance("张刚", 2);                        //通过有参构造创建对象
   //Field f = clazz.getField("name");								//获取姓名字段
   //f.set(p, "李四");												//修改姓名的值
   Field f = clazz.getDeclaredField("name");                 //如果name字段是private权限 暴力反射获取字段
   f.setAccessible(true);                                          //去除私有权限
   f.set(p, "李四");
   //name字段的类型
   Class<?> type = f.getType();
   System.out.println(type);
   System.out.println(p);
    }

 public static void main(String[] args) throws Exception {
  Class clazz = Class.forName("cn.yx.zg.反射.demo3.Person");
  Constructor c = clazz.getConstructor(String.class, int.class);    //获取有参构造
  Person p = (Person) c.newInstance("张三", 23);                        //通过有参构造创建对象
  Method m = clazz.getMethod("eat");                                //获取eat方法
  m.invoke(p);
  Method m2 = clazz.getMethod("eat", int.class);                    //获取有参的eat方法
  m2.invoke(p, 10);
 }