Java中Reflect的基本使用

首先在package reflect下定义了一个类Book

 package reflect;

 class Book{
     private String title;
     private double price;
     public Book() {
         this("Java开发", 20.00);
     }
     public Book(String title, double price) {
         this.title = title;
         this.price = price;
     }
     public String getTitle() {
         return title;
     }
     public void setTitle(String title) {
         this.title = title;
     }
     public double getPrice() {
         return price;
     }
     public void setPrice(double price) {
         this.price = price;
     }
     @Override
     public String toString() {
         return "标题: " + this.title + ", 价格：" + this.price;
     }
 }

 package reflect;

 import java.lang.reflect.Constructor;
 import java.lang.reflect.Method;
 import java.util.Arrays;

 public class Reflect {
     public static void main(String[] args) throws Exception {
         /**
          * 通过Class.forName(String str)方法获取Class实例cls
          * 通过getConstructor(parameterTypes)获取构造方法
          * 通过get。。。获取 public的属性， 方法
          * 通过getDeclared。。。获取public，protected， private属性， 方法
          * 通过newInstance(parameterTypes)构造对象
          */
         Class<?> cls = Class.forName("reflect.Book");
          Constructor<?> con = cls.getConstructor(String.class, double.class);
          Object obj = con.newInstance("你好", 2.5);
          System.out.println(obj);
          Method[] methods = cls.getDeclaredMethods();
 //         System.out.println(Arrays.toString(methods));
          Method setTitle = cls.getMethod("setTitle", String.class);
           Method getTitle = cls.getMethod("getTitle");
           // 通过invoke(obj, paramter)执行获取的方法
           setTitle.invoke(obj, "我好!");
           System.out.println(getTitle.invoke(obj));
           System.out.println(obj);
     }
 }