首先需求是这样的 ，我把它简化一下：
User user1=new User();
user1.setUserName("wxn");
User user2=new User();
user2.setUserName("kkkk");
User user3=user2;
接下来的操作我想让user2中的值和user1中的值全部相等。我们知道可以通过 user2=user1.clone()方法去获得一个新的对象，这种方法的详细介绍在这里可以学习。http://www.cnblogs.com/yxnchinahlj/archive/2010/09/20/1831615.html
但是这样clone出来的是一个新的对象，user2就是user1的一个新对象的拷贝，虽然user2中的值可以和user1中的值相等，但是 user3就已经不是user2之前的对象了，我需要user3中的值也跟着改变。
于是最简单的方法就是在User类中增加一个方法
public void copy(User user){
this.setUserName(user.getUserName);
this.setUserId(user.setUserId);
.....
}
如果user中的属性太多怎么办？那写起来太麻烦了，除了方法名get和set有区别之外没什么区别， 于是我想起了之前看过的java反射机制来批量处理，顺便巩固一下java的反射机制，实现代码如下
public void copy(User user) {
//获得User类中所有的方法
Method[] methods = user.getClass().getMethods();
try {
for (int i = 0; i < methods.length; i++) {
String mName = methods[i].getName();
if (mName.startsWith("set")) {
String nName =null;
//若为boolean的属性则没有get方法 只有 isXXX方法
if(boolean.class.equals(methods[i].getParameterTypes()[0]) ){
nName=mName.replace("set", "is");
} else{
nName=mName.replace("set", "get");
}
Method method = user.getClass().getDeclaredMethod(nName,
null);
methods[i].invoke(this, method.invoke(user, null));
}
}
} catch (IllegalArgumentException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IllegalAccessException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (InvocationTargetException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (NoSuchMethodException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
全部代码如下
import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
/**
*
* @author ahsiu
*
*/
public class User {
private int userId;
private String userName;
private String password;
private String email;
private String phone;
private int loginState;
private boolean flag;
public int getUserId() {
return userId;
}
public void copy(User user) {
Method[] methods = user.getClass().getMethods();
try {
for (int i = 0; i < methods.length; i++) {
String mName = methods[i].getName();
if (mName.startsWith("set")) {
String nName =null;
//若为boolean的属性则没有get方法 只有 isXXX方法
if(boolean.class.equals(methods[i].getParameterTypes()[0]) ){
nName=mName.replace("set", "is");
} else{
nName=mName.replace("set", "get");
}
Method method = user.getClass().getDeclaredMethod(nName,
null);
methods[i].invoke(this, method.invoke(user, null));
}
}
} catch (IllegalArgumentException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IllegalAccessException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (InvocationTargetException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (NoSuchMethodException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public void setUserId(int userId) {
this.userId = userId;
}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
public String getPhone() {
return phone;
}
public void setPhone(String phone) {
this.phone = phone;
}
public int getLoginState() {
return loginState;
}
public void setLoginState(int loginState) {
this.loginState = loginState;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
public String getUserName() {
return userName;
}
public void setUserName(String userName) {
this.userName = userName;
}
public boolean isFlag() {
return flag;
}
public void setFlag(boolean flag) {
this.flag = flag;
}
public static void main(String[] args) {
User user1=new User();
user1.setUserName("wxn");
User user2=new User();
user2.setUserName("kkkk");
User user3=user2;
System.out.println(user1.getUserName());
System.out.println(user2.getUserName());
System.out.println(user3.getUserName());
System.out.println("");
user2.copy(user1);
System.out.println(user1.getUserName());
System.out.println(user2.getUserName());
System.out.println(user3.getUserName());
System.out.println("");
user3.setUserName("ahsiu");
System.out.println(user1.getUserName());
System.out.println(user2.getUserName());
System.out.println(user3.getUserName());
}
}
