Java中的反射机制（二） 一个利用反射进行对象拷贝的例子

import java.lang.reflect.Constructor;import java.lang.reflect.Field;import java.lang.reflect.Method;public class ReflectTester{    // 该方法实现对Customer对象的拷贝操作    public Object copy(Object object) throws Exception    {        Class<?> classType = object.getClass();        /* 生成新的对象的讨论        // 获得Constructor对象,此处获取第一个无参数的构造方法的        Constructor cons = classType.getConstructor(new Class[] {});//不带参数，所以传入一个为空的数组        // 通过构造方法来生成一个对象        Object obj = cons.newInstance(new Object[] {});        // 以上两行代码等价于：        Object obj11 = classType.newInstance();  // 这行代码无法处理构造函数有参数的情况                //用第二个带参数的构造方法生成对象        Constructor cons2 = classType.getConstructor(new Class[] {String.class, int.class});        Object obj2 = cons2.newInstance(new Object[] {"ZhangSan",20});                */                Object objectCopy = classType.getConstructor(new Class[]{}).newInstance(new Object[]{});                //获得对象的所有成员变量        Field[] fields = classType.getDeclaredFields();        for(Field field : fields)        {            //获取成员变量的名字            String name = field.getName();    //获取成员变量的名字，此处为id，name,age            //System.out.println(name);            //获取get和set方法的名字            String firstLetter = name.substring(0,1).toUpperCase();    //将属性的首字母转换为大写                        String getMethodName = "get" + firstLetter + name.substring(1);            String setMethodName = "set" + firstLetter + name.substring(1);                        //System.out.println(getMethodName + "," + setMethodName);                        //获取方法对象            Method getMethod = classType.getMethod(getMethodName, new Class[]{});            Method setMethod = classType.getMethod(setMethodName, new Class[]{field.getType()});//注意set方法需要传入参数类型                        //调用get方法获取旧的对象的值            Object value = getMethod.invoke(object, new Object[]{});            //调用set方法将这个值复制到新的对象中去            setMethod.invoke(objectCopy, new Object[]{value});        }        return objectCopy;    }    public static void main(String[] args) throws Exception    {        Customer customer = new Customer("Tom",20);        customer.setId(1L);        ReflectTester tester = new ReflectTester();                Customer customer2 = (Customer)tester.copy(customer);                System.out.println(customer2.getId() + "," + customer2.getName() + "," + customer2.getAge());            }}class Customer{    private long id;    private String name;    private int age;    public Customer()    {    }    public Customer(String name, int age)    {        this.name = name;        this.age = age;    }    public long getId()    {        return id;    }    public void setId(long id)    {        this.id = id;    }    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;    }}