1. Phase II of the project - user registration and login

The second stage —— User registration and login

1、JavaEE The three-tier architecture of the project

The purpose of layering is to decouple . Decoupling is to reduce the coupling of code . It is convenient for the maintenance and upgrading of the project later .

web layer com.my.book.web/servlet/controller

service layer com.my.book.service Service Interface package

com.my.book.service.impl Service Interface implementation class

dao Persistence layer com.my.book.dao Dao Interface package

com.my.book.dao.impl Dao Interface implementation class

Entity bean object com.my.book.pojo/entity/domain/bean JavaBean class

Test package com.my.book.test/junit

Tool class com.my.book.util

Build a Book City project development environment ：

2、 First create the database and tables required by the book city .

database

drop database if exists book;
create database book;
use book;
create table t_user(
id int primary key auto_increment,
username varchar(20) not null unique,
password varchar(32) not null,
email varchar(200)
);
insert into t_user(username,password,email) values(admin,123,[email protected]);
select * from t_user;

3、 Write the corresponding database table JavaBean object

public class User {
​
    private Integer id;
    private  String username;
    private String password;
    private  String email;
​
    public Integer getId() {
        return id;
    }
​
    public void setId(Integer id) {
        this.id = id;
    }
​
    public String getUsername() {
        return username;
    }
​
    public void setUsername(String username) {
        this.username = username;
    }
​
    public String getPassword() {
        return password;
    }
​
    public void setPassword(String password) {
        this.password = password;
    }
​
    public String getEmail() {
        return email;
    }
​
    public void setEmail(String email) {
        this.email = email;
    }
​
    public User(Integer id, String username, String password, String email) {
        this.id = id;
        this.username = username;
        this.password = password;
        this.email = email;
    }
​
    public User() {
    }
}
​

4、 Write a tool class JdbcUtils

4.1、 Import required jar package （ The database and connection pool need ）：

4.2、 stay src Source code directory under the preparation of jdbc.properties Properties profile ：

username=root
password=root
url=jdbc:mysql://localhost:3306/book
driverClassName=com.mysql.jdbc.Driver
initialSize=5
maxActive=10

4.3、 To write JdbcUtils Tool class ：

public class JdbcUtils {
    private static DruidDataSource dataSource;
    static {
        try {
            Properties properties = new Properties();
            //  Read  jdbc.properties  Properties profile 
            InputStream inputStream =
            JdbcUtils.class.getClassLoader().getResourceAsStream("jdbc.properties");
            //  Loading data from a stream 
            properties.load(inputStream);
            //  establish   Database connection   pool 
            dataSource = (DruidDataSource) DruidDataSourceFactory.createDataSource(properties);
            } catch (Exception e) {
                e.printStackTrace();
        }
    }
        /**
        *  Get the connections in the database connection pool 
        *  If you return  null, Failed to get the connection <br/> A value is a successful connection 
        */
    public static Connection getConnection(){
        Connection conn = null;
        try {
            conn = dataSource.getConnection();
        } catch (Exception e) {
            e.printStackTrace();
        }
        return conn;
    }
    /**
    *  Close the connection , Put back the database connection pool 
    * @param conn
    */
    public static void close(Connection conn){
        if (conn != null) {
            try {
                conn.close();
            } catch (SQLException e) {
                    e.printStackTrace();
                }
            }
        }
}

4.4、JdbcUtils test

public class JdbcUtilsTest {
    @Test
    public void testJdbcUtils(){
    for (int i = 0; i < 100; i++){
        Connection connection = JdbcUtils.getConnection();
        System.out.println(connection);
        JdbcUtils.close(connection);// Remember to turn it off after use 
        }
    }
}

This indicates that the connection is successful

5、 To write BaseDao

5.1、 Guide pack

Remember to guide before use DBUtils Of jar package

5.2、 To write BaseDao：

public abstract class BaseDao {
​
    // Use DbUtils Operating the database 
    private QueryRunner queryRunner = new QueryRunner();
​
    /**
     * update()  Method to execute ：Insert\Update\Delete sentence 
     *
     * @return  If you return -1, Description the number of other rows that are affected by the execution failure 
     */
    public int update(String sql, Object... args) {
        Connection connection = JdbcUtils.getConnection();
        try {
            return queryRunner.update(connection, sql, args);
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            JdbcUtils.close(connection);
        }
        return -1;
    }
​
    /**
     *  The query returns a javaBean Of sql sentence 
     *
     * @param type  Object type returned 
     * @param sql   Executive sql sentence 
     * @param args sql The corresponding parameter value 
     * @param <T>   The generic type of the returned type 
     * @return
     */
    public <T> T queryForOne(Class<T> type, String sql, Object... args) {
        Connection con = JdbcUtils.getConnection();
        try {
            return queryRunner.query(con, sql, new BeanHandler<T>(type), args);
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            JdbcUtils.close(con);// Closed flow 
        }
        return null;
    }
​
    /**
     *  The query returns multiple javaBean Of sql sentence 
     *
     * @param type  Object type returned 
     * @param sql   Executive sql sentence 
     * @param args sql The corresponding parameter value 
     * @param <T>   The generic type of the returned type 
     * @return
     */
    public <T> List<T> queryForList(Class<T> type, String sql, Object... args) {
        Connection con = JdbcUtils.getConnection();
        try {
            return queryRunner.query(con, sql, new BeanListHandler<T>(type), args);
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            JdbcUtils.close(con);
        }
        return null;
    }
​
    /**
     *  Execution returns row by column sql sentence 
     * @param sql    Executive sql sentence 
     * @param args  sql The corresponding parameter value 
     * @return
     */
    public Object queryForSingleValue(String sql, Object... args){
​
        Connection conn = JdbcUtils.getConnection();
        try {
            return queryRunner.query(conn, sql, new ScalarHandler(), args);
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            JdbcUtils.close(conn);
        }
        return null;
    }
​
​

6、 To write UserDao And testing

6.1、UserDao Interface ：

public interface UserDao {
​
    /**
     *  Query user information according to user name 
     * @param username  user name 
     * @return  If you return null, It means that there is no such user . vice versa 
     */
    public User queryUserByUsername(String username);
​
    /**
     *  according to   User name and password query user information 
     * @param username
     * @param password
     * @return  If you return null, User name or password error , vice versa 
     */
    public User queryUserByUsernameAndPassword(String username,String password);
​
    /**
     *  Save user information 
     * @param user
     * @return  return -1 Indicates that the operation failed , The others are sql The number of lines affected by the statement 
     */
    public int saveUser(User user);
​
}

6.2、UserDaoImpl Implementation class

public class UserDaoImpl extends BaseDao implements UserDao {
​
    // According to the inquiry username
    @Override
    public User queryUserByUsername(String username) {
        String sql = "select username,password,email from t_user where username = ?";
        return queryForOne(User.class, sql, username);
    }
​
    @Override
    public User queryUserByUsernameAndPassword(String username, String password) {
        String sql = "select id,username,password,email from t_user where username = ? and password = ?";
        return queryForOne(User.class, sql, username,password);
    }
​
    // Save the data 
    @Override
    public int saveUser(User user) {
        String sql = "insert into t_user(username,password,email) values(?,?,?)";
        return update(sql, user.getUsername(),user.getPassword(),user.getEmail());
    }
}

6.3UserDao test ：

public class UserDaoTest {

    UserDao userDao=new UserDaoImpl();
    @Test
    public void queryUserByUsername() {

        if(userDao.queryUserByUsername("admin")==null){
            System.out.println(" User available ！");
        }else{
            System.out.println(" The user already exists ");
        }

    }

    @Test
    public void saveUser() {
        System.out.println();
    }

    @Test
    public void queryUserByUsernameAndPassword() {
       if(userDao.queryUserByUsernameAndPassword("admin","123")==null){
           System.out.println(" User password error , Login failed ");
        }else{
           System.out.println(" The query is successful ");
       }
    }

7、 To write UserService Sum measurement

7.1UserService Interface

public interface UserService {
    // Registered users 
    public void registUser(User user);
    // Sign in 
    public User login(User user);

    // Check whether the user is available 
    //true Indicates that the user name exists 
    public boolean existsUsername(String username);
}

7.2、UserServiceImpl Implementation class ：

public class UserServiceImpl implements UserService{

  UserDao userDao=new UserDaoImpl();
    @Override
    public void registUser(User user) {
        userDao.saveUser(user);

    }

    @Override
    public User login(User user) {
      return userDao.queryUserByUsernameAndPassword(user.getUsername(),user.getPassword());
      
    }

    @Override
    public boolean existsUsername(String username) {
        if (userDao.queryUserByUsername(username)==null) {
            // be equal to null That means we didn't find , conversely 
            return false;
        }
        return true;
    }
}

7.3、UserService test ：

public class UserServiceTest {

    UserService userService=new UserServiceImpl();
    @Test
    public void registUser() {
        userService.registUser(new User(null,"pjh","666","[email protected]"));
        userService.registUser(new User(null,"zjt","555","[email protected]"));
    }

    @Test
    public void login() {
        System.out.println(userService.login(new User(null,"pjh","666","[email protected]")));
    }

    @Test
    public void existsUsername() {
        if (userService.existsUsername("pjh168")) {
            System.out.println(" User name already exists ！");
        } else {
            System.out.println(" User name available ！");
        }
    }

8、 To write web layer

8.1、 Realize the function of user registration

8.1.1、 Illustrate the process of user registration ：

8.1.2、 modify regist.html and regist_success.html page

1、 add to base mark

<!-- Write  base  label , Always fix the result of relative path jump -->
<base href="http://localhost:8080/book/">

2、 modify base The effect of tags on all relative paths in the page （ browser F12, Which report red , Which one ）

<link type="text/css" rel="stylesheet" href="static/css/style.css" >
<script type="text/javascript" src="static/script/jquery-1.7.2.js"></script>

3、 Modify the submission address and request method of the registration form

8.1.3、 To write RegistServlet Program

public class RegistServlet extends HttpServlet {
    private UserService userService=new UserServiceImpl();



    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
    // Get the requested parameters 
        String username = req.getParameter("username");
        String password = req.getParameter("password");
        String email = req.getParameter("email");
        String code = req.getParameter("code");
    // The verification code is required to be ABCD
        if("abcd".equalsIgnoreCase(code)){
            // correct 
            // Check if the user name is available 
            if(userService.existsUsername(username)){
                // Unavailable 
                System.out.println(" user name ["+username+"] Already exists ");
                //  Jump back to the registration page 
                req.getRequestDispatcher("/pages/user/regist.html").forward(req,resp);
            }else{
                // You can use , call service Save to database 
                userService.registUser(new User(null,username,password,email));
                //   Jump to registration succeeded register——success.html
                req.getRequestDispatcher("/pages/user/regist_success.html").forward(req,resp);
            }

        }else{
            // Jump back to the registration page 
            System.out.println(" Verification Code ["+code+"] error ");
            req.getRequestDispatcher("/pages/user/regist.html").forward(req,resp);
        }

    }
}

8.2、IDEA in Debug Debug the

8.2.1、Debug Debugging code , First, you need two elements ： The breakpoint + Debug Start the server

1、 The breakpoint , Just click to the left of the line where the code needs to stop , You can add and cancel

2、Debug start-up Tomcat

8.2.2、 Test toolbar ：

8.2.3、 Other commonly used debugging related buttons ：

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8.3、 The realization of user login function ：

8.3.1、 Graphical user login

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8.3.2、 modify login.html Page and login_success.html page

1、 add to base mark

<!-- Write  base  label , Always fix the result of relative path jump -->
<base href="http://localhost:8080/book/">

2 modify login.html Form submission address and request method

8.3.3、LoginServlet Program

public class LoginServlet extends HttpServlet {

    private UserService userService = new UserServiceImpl();

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //  1、 Get the requested parameters 
        String username = req.getParameter("username");
        String password = req.getParameter("password");
        //  call  userService.login() Log in to handle business 
        User loginUser = userService.login(new User(null, username, password, null));

        //  If it is equal to null, Description login   Failure !
        if (loginUser == null) {
            //    Jump back to the login page 
            req.getRequestDispatcher("/pages/user/login.html").forward(req, resp);
        } else {
            //  Sign in   success 
            // Skip to success page login_success.html
            req.getRequestDispatcher("/pages/user/login_success.html").forward(req, resp);
        }
    }
}

summary

2. Project phase II ： Implementation of user registration and login .

demand 1： User registration

Requirements are as follows ：

1） Visit the registration page

2） Fill in registration information , Submit to server

3） The server should save the user

4） When the user already exists ---- Prompt the user to register Failure , User name already exists

5） When the user doesn't exist ----- Registered successfully

demand 2： The user login

Requirements are as follows ：

1） Visit the landing page

2） Fill in the user name and password and submit

3） The server determines whether the user exists

4） If login fails —>>>> Return user name or password error information

5） If login is successful —>>>>