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This article mainly introduces "how to use io to achieve user login". In daily operation, I believe that many people have doubts about how to use io to achieve user login. Xiaobian consulted all kinds of materials and sorted out simple and easy-to-use operation methods. I hope it will be helpful to answer the doubts of "how to use io to achieve user login". Next, please follow the editor to study!

User login

Complete the system login program, enter the user name and password from the command line, and prompt for the user name and password if you do not enter the user name and password If the user name is entered but no password is entered, the user is prompted to enter the password, and then determine whether the user name is mldn and the password is hello. If it is correct, the login is successful. If it is wrong, the login failure information is displayed. The user enters the user name and password again, and the system exits after entering errors for 3 times in a row.

For the program at this time, it is found that the user name and password can be entered at the same time, or you can enter the user name first, and then enter the password, if more than 3 times means that the login is over. The use of username and password can be done in the form of "username / password". If no "/" is found, no password has been entered.

1. Define the user's operation interface

Public interface IUserService {public boolean isExit (); public boolean login (String name,String password);}

2. Define the subclass of the operation interface

Import cn.mldn.demo.service.IUserService;public class UserServiceImpl implements IUserService {private int count = 0; / as login statistics @ Overridepublic boolean isExit () {return this.count > = 3; / / condition for performing login exit} @ Overridepublic boolean login (String name, String password) {this.count + +; return "mldn" .equals (name) & & "hello" .equals (password);}}

3. For the detection and processing operation of login failure, a user's agent operation class should be defined separately.

Import cn.mldn.demo.service.IUserService;public class UserServiceProxy implements IUserService {private IUserService userService; public UserServiceProxy (IUserService userService) {this.userService = userService;} @ Overridepublic boolean login (String name, String password) {while (! this.isExit ()) {/ / do not exit String inputData = inputUtil.getString ("Please enter login information:"); if (inputData.contains ("/")) {/ / enter the user name and password String temp [] = inputData.split ("/") / / data split if (this.userService.login (temp [0], temp [1])) {/ / login authentication return true; / / cycle ends} else {System.out.println ("login failed, wrong username or password!") ;} else {/ / now only user name String pwd = inputUtil.getString ("Please enter password:"); if (this.userService.login (inputData, pwd)) {/ / login authentication return true; / / cycle ends} else {System.out.println ("login failed, wrong username or password!") ;} return false; @ Overridepublic boolean isExit () {return this.userService.isExit ();}}

4. Modify the factory class definition

Import cn.mldn.demo.service.IUserService;import cn.mldn.demo.service.impl.UserServiceImpl;import cn.mldn.demo.service.proxy.UserServiceProxy;public class Factory {private Factory () {} public static IUserService getInstance () {return new UserServiceProxy ();}}

5. Define test class processing:

Public class IOCaseDemo {public static void main (String [] args) {System.out.println (Factory.getInstance.login (null, null));}}

Execution result:

The real business only implements the core functions, and the auxiliary logic processing is handed over to the agent to control.

At this point, the study on "how to use io to achieve user login" is over. I hope to be able to solve your doubts. The collocation of theory and practice can better help you learn, go and try it! If you want to continue to learn more related knowledge, please continue to follow the website, the editor will continue to work hard to bring you more practical articles!

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