实例化对象的两种形式：

1）通过关键字new

2）通过反射机制完成

package test;//Book类class Book {    private String title;    private double  price;    public void setPric(double price) {        this.price = price;    }    public void setTitle(String title) {        this.title = title;    }    @Override    public String toString() {        return "图书名称:"+ title + " 价格:" + price;    }}public class TestReflection {    public static void main(String[] args) throws Exception {        Class
      cls = Class.forName("test.Book"); //包名.类名        Book book = (Book) cls.newInstance();        book.setTitle("Java");        book.setPric(10.01);        System.out.println(book.toString()); //图书名称:Java 价格:10.01    }}

 Q：如果类中没有提供无参构造方法，只提供了有参构造方法，则必须明确调用指定的构造方法才可以通过反射实例化对象

package test;import java.lang.reflect.Constructor;//Book类class Book {    private String title;    private double  price;    public Book(String title,double price){        this.price = price;        this.title = title;    }            @Override    public String toString() {        return "图书名称:"+ title + " 价格:" + price;    }}public class TestReflection {    public static void main(String[] args) throws Exception {        Class
      cls = Class.forName("test.Book");        Constructor
      cons = cls.getConstructor(String.class,double.class);        Book book = (Book) cons.newInstance("Java",10.01);        System.out.println(book.toString());                //图书名称:Java 价格:10.01    }}