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; }}