反射 黑马程序员

public class ReflectTester {
 public Object copy(Object object) throws Exception {
  // 获得对象的类型
  Class<?> classType = object.getClass();
  System.out.println("Class:" + classType.getName());
  // 通过默认构造方法创建一个新的对象，new Class[] {} 没参数表示用默认的构造方法
  Object objectCopy = classType.getConstructor(new Class[] {})
    .newInstance(new Object[] {});
  // 获得对象的所有属性，包括私有的
  Field fields[] = classType.getDeclaredFields();
  for (int i = 0; i < fields.length; i++) {
   Field field = fields[i];
   String fieldName = field.getName();
   String firstLetter = fieldName.substring(0, 1).toUpperCase();
   // 获得和属性对应的getXXX()方法的名字
   String getMethodName = "get" + firstLetter + fieldName.substring(1);
   // 获得和属性对应的setXXX()方法的名字
   String setMethodName = "set" + firstLetter + fieldName.substring(1);
   // 获得和属性对应的getXXX()方法 ，根据名字和参数取得对应的方法,getXXX()是没参数的，所以传个空的
   Method getMethod = classType.getMethod(getMethodName,
     new Class[] {});
   // 获得和属性对应的setXXX()方法，setXXX(Object obj)，setXXX是有参数的，所以传当前字段的类型
   Method setMethod = classType.getMethod(setMethodName,
     new Class[] { field.getType() });
   // 调用原对象的getXXX()方法，调用getXXX()取得原对象的值
   Object value = getMethod.invoke(object, new Object[] {});
   System.out.println(fieldName + ":" + value);
   // 调用拷贝对象的setXXX()方法，调用新对象的setXXX()把值设置进去
   setMethod.invoke(objectCopy, new Object[] { value });
  }
  return objectCopy;
 }
 public static void main(String[] args) throws Exception {
  Customer customer = new Customer("Shmilyzl", 25);
  customer.setId(new Long(1));
  Customer customerCopy = (Customer) new ReflectTester().copy(customer);
  System.out.println("Copy information:" + customerCopy.getId() + " "
    + customerCopy.getName() + " " + customerCopy.getAge());
 }
}

package com.fahon.mytest;
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;
 }
}

Class:com.fahon.mytest.Customer
id:1
name:Shmilyzl
age:25
Copy information:1 Shmilyzl 25