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Java adalah aplikasi web sederhana. Login dan registrasi

Hari baik untuk semua


Artikel ini ditujukan untuk pemula di dunia Web dan Java. Kami akan melihat arsitektur aplikasi web standar dan membuat proyek kecil dari awal.


Kami akan menggunakan Spring (Kerangka kerja web yang besar), tetapi setidaknya. Jika Anda tidak memiliki pengalaman sebelumnya dalam menggunakan dan segera mencoba menggunakan semua fungsi, maka tidak akan ada pemahaman dasar, karena ada daftar jebakan.


Apa yang akan dilakukan aplikasi?


Saya ingin menyajikan contoh singkat yang bermanfaat sekaligus bermanfaat. Ini dimuat minimal dan pada akhirnya Anda dapat menggunakannya sebagai templat.


Berpikir tentang apa yang sering dihadapi orang ketika mengembangkan aplikasi web, saya menyadari bahwa implementasi login dan registrasi akan sangat terbuka dan bermanfaat.


Anda dapat menemukan kode sumber di sini .


Apa yang akan kita gunakan


  • IDE favorit (Saya menggunakan IntelliJ IDEA)
  • kepala tidak mendung
  • Maven (pembangun proyek)
  • JDBC (tautan antara Java dan DBMS)

Pembuatan proyek


Buat proyek Maven sederhana. Kami melakukan semuanya dari awal, tanpa menambahkan arketipe apa pun.
IDE harus menghasilkan struktur seperti itu.


gambar


Jadi apa yang kita lihat.


  • java - tempat utama di mana "sihir" akan terjadi
  • resources — . ( , , front )
  • test — . ( , )
  • pom.xml — Maven. , , "" .

, IDE, - Maven.


gambar


-


, .
, .


gambar


-, , "-".


.


  1. Browser — . Frontend. Backend — , . .
  2. Controller — Frontend, . , , .
  3. Service — - . . .
  4. DAL(data access layer) — . , , , .
  5. Database — , .


- .


, H2.


, -. User.


create table DATABASE.USER
(
    ID INT auto_increment,
    NAME VARCHAR not null,
    SURNAME VARCHAR not null,
    LOGIN VARCHAR not null,
    PASSWORD VARCHAR not null,
    constraint USER_PK
        primary key (ID)
);

Spring


java.


java com.zuk( ), App main .


Spring. , @SpringBootApplication Spring, , . Spring .


//com.zuk.App
@SpringBootApplication
public class App {

    public static void main(String[] args) {
        SpringApplication.run(App.class, args);
    }
}

pom.xml.


<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>org.zuk</groupId>
    <artifactId>LoginAndRegistration</artifactId>
    <version>1.0-SNAPSHOT</version>

    <properties>
        <maven.compiler.source>1.8</maven.compiler.source>
        <maven.compiler.target>1.8</maven.compiler.target>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
            <version>2.2.5.RELEASE</version>
        </dependency>
    </dependencies>

</project>

, Spring .


gambar


Spring 8080. , http://localhost:8080.



, Spring , .


application.properties src.main.resources.


-.


spring.datasource.driverClassName=org.h2.Driver
spring.datasource.url=jdbc:h2:~/test

spring.datasource.username=sa
spring.datasource.password=

Spring, .


, .
, . , . Spring .
.


java.com.zuk.connection ConnectionManager, , .
properties, FileInputStream.


//ConnectionManager
FileInputStream fis;
Properties property = new Properties();

application.properties, properties.


//ConnectionManager
fis = new FileInputStream("src/main/resources/application.properties");
property.load(fis);

getConnection.


  //ConnectionManager
  public Connection getConnection() {
            Connection connection = null;
            try {
                connection = DriverManager.getConnection(property.getProperty("spring.datasource.url"),property.getProperty("spring.datasource.username"),property.getProperty("spring.datasource.password"));
            } catch (SQLException e) {
                e.printStackTrace();
            }
            return connection;
        }

, App.


, .


conn2: url=jdbc:h2:~/test user=SA

, pom.


<dependency>
    <groupId>com.h2database</groupId>
    <artifactId>h2</artifactId>
    <version>1.4.200</version>
</dependency>

POJO (Plain Old Java Objects)


, , .


, , . , , , . , , . POJO.


, User.
.


java.com.zuk.entity, User.
, .


User.java
public class User {

    private int id;
    private String name;
    private String surname;
    private String login;
    private String password;

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getSurname() {
        return surname;
    }

    public void setSurname(String surname) {
        this.surname = surname;
    }

    public String getLogin() {
        return login;
    }

    public void setLogin(String login) {
        this.login = login;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

}

DAL


, , DAL. , . DAO (data access object) — - .


java.com.zuk.dao UserDao ( ). findByLogin, save.


public interface UserDao {
    User findByLogin(String login);
    Boolean save(User user);
}

, java.com.zuk.dao.impl,
UserDaoImpl.
— , , (, ).


public class UserDaoImpl implements UserDao {
    @Override
    public User findByLogin(String login) {
        return null;
    }

    @Override
    public Boolean save(User user) {
        return null;
    }
}

findByLogin. SQL .


SELECT  * from DATABASE.User where LOGIN=login

User.


, null.


//UserDaoImpl
ConnectionManager cm = new ConnectionManager();
Connection con = cm.getConnection();

@Override
    public User findByLogin(String login) {
        User user = null;
        if (con != null) {
              //..  
        }
        return user;
     }

if , SQL , user.


//findByLogin
PreparedStatement pr = con.prepareStatement("SELECT * FROM DATABASE.User where LOGIN=?");
pr.setString(1 , login);
ResultSet resultSet = pr.executeQuery();//return sql result
if(resultSet.next()) {
       user = new User();
       user.setId(resultSet.getInt("ID"));
       user.setName(resultSet.getString("NAME"));
       user.setSurname(resultSet.getString("SURNAME"));
       user.setLogin(login);
       user.setPassword(resultSet.getString("PASSWORD"));
       return user;
}
 pr.close();
 con.close();

.


save .
.


save
//UserDaoImpl
@Override
    public Boolean save(User user) {
        ConnectionManager cm = new ConnectionManager();
        Connection con = cm.getConnection();
        if (con != null) {
            try {
                PreparedStatement pr = con.prepareStatement("insert into DATABASE.USER (NAME,SURNAME,LOGIN,PASSWORD) values (?,?,?,?)");
                pr.setString(1,user.getName());
                pr.setString(2,user.getSurname());
                pr.setString(3,user.getLogin());
                pr.setString(4, DigestUtils.md5DigestAsHex((user.getPassword()).getBytes()));
                pr.executeUpdate();
                pr.close();
                con.close();
                return true;
            } catch (SQLException e) {
                e.printStackTrace();

            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        return false;
    }

Service


-. java.com.zuk.service, UserService : login, registration. UserServiceImpl java.com.zuk.service.impl, UserService.


public class UserServiceImpl implements UserService {
    @Override
    public String login(User user) {
        return null;
    }

    @Override
    public String registration(User user) {
        return null;
    }
}

login.
:


  1. "login" .
  2. 1 , .
  3. 2 , "life is beautiful"

//UserServiceImpl
UserDaoImpl userDao = new UserDaoImpl();
    @Override
    public String login(User user) {
        User findUser = userDao.findByLogin(user.getLogin());
        if(findUser!=null){
            if(DigestUtils.md5DigestAsHex((user.getPassword()).getBytes()).equals(findUser.getPassword())){
                return "life is beautiful"  + "your Id: " + findUser.getId();
            }
        }
        return "do not give up";
    }

.


registration
 @Override
    public String registration(User user) {
        User findUser = userDao.findByLogin(user.getLogin());
        if(findUser==null) {
            userDao.save(user);
            return "life is beautiful";
        }
        return "this login is not available";
    }

Controller


, - .
java.com.zuk.controller Controller. "" RestController, Spring , Rest Controller.
, @RequestMapping("/").


@RestController
public class Controller {
    @RequestMapping("/")
    String main() {
        return "Hello from Controller";
    }
}

, http://localhost:8080.
"Hello from Controller".


html . , .
resources, resources.static.


html
<!--loginFrom.html-->
<html>
<title>Login</title>
<body>
<form action="http://localhost:8080/login"  method="post">
    <input type="text" required name="login" placeholder="login" />
    <input type="password" required name="password" placeholder="password" />
    <button>login</button>
</form>
<a href="http://localhost:8080/registrationForm">don't have account</a>
</body>
</html>

<!--registrationForm.html-->
<html>
<title>Registration</title>
<body>
<form action="http://localhost:8080/registration"  method="post">
    <input type="text" required name="name" placeholder="name" />
    <input type="text" required name="surname" placeholder="surname" />
    <input type="text" required name="login" placeholder="login" />
    <input type="password" required name="password" placeholder="password" />
    <button>registration</button>
</form>
<a href="http://localhost:8080/loginForm">already have account</a>
</body>
</html>

, http://localhost:8080/loginForm, http://localhost:8080/registrationForm html .
, /loginForm, /registrationForm html. ModelAndView.


//Controller
 @RequestMapping("/loginForm")
    ModelAndView loginForm() {
        ModelAndView modelAndView = new ModelAndView();
        modelAndView.setViewName("loginForm.html");
        return modelAndView;
    }

    @RequestMapping("/registrationForm")
    ModelAndView registrationForm() {
        ModelAndView modelAndView = new ModelAndView();
        modelAndView.setViewName("registrationForm.html");
        return modelAndView;
    }

, action http://localhost:8080/login registration, .
service.


//Controller
UserServiceImpl userService = new UserServiceImpl();
//..
 @PostMapping("/login")
    String login(@RequestParam String login,@RequestParam String password) {
        User user = new User();
        user.setLogin(login);
        user.setPassword(password);
        return userService.login(user);
    }

    @PostMapping("/registration")
    String registration(@RequestParam String name,@RequestParam String surname, @RequestParam String login,@RequestParam String password) {
        User user = new User();
        user.setName(name);
        user.setSurname(surname);
        user.setLogin(login);
        user.setPassword(password);
        return userService.registration(user);
    }

Kami melihat bahwa metode kami di Controller mulai menerima parameter. Ini adalah parameter yang kami tulis di formulir kami. Nama mereka harus cocok dengan input nama.


Kesimpulan


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