SpringBoot learning to realize the login and registration function

1. System directory structure

2. Create a database

Database name: student, data table: user, the creation command is as follows:

//创建数据库
create database student;

//选择创建好的数据库，建立user表
use student;

create table user(
    id int primary key auto_increment,
    username varchar(32) unique not null,
    password varchar(32) not null
);


//想创建好的数据库中添加数据
insert into user values(1,"xioming","000");

//查看自己添加的数据
select * from user;

3. Create a front-end page

3.1 Login page: login.html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>login</title>
</head>
<body>
    <form method="post" action="/user/login">
        用户名：<input name="username" type="text"/>
        密码：<input name="password" type="password"/>
        <input type="submit" value="登录验证">
        <input type="button" onclick="javascript:window.location.href='regist.html'" value="去注册页面">
    </form>
</body>
</html>

3.2 Registration page: regist.html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>regist</title>
</head>
<body>
    <form method="post" action="/user/regist">
        用户名：<input name="username" type="text"/>
        密码：<input name="password" type="password"/>
        <input type="submit" value="注册校验">
        <input type="button" onclick="javascript:window.location.href='login.html'" value="返回注册页面">

    </form>
</body>
</html>

4. Java code

4.1 pom tree

<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.3.4.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.example</groupId>
    <artifactId>studentsys</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>studentsys</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>11</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-jdbc</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>2.1.3</version>
        </dependency>

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
            <exclusions>
                <exclusion>
                    <groupId>org.junit.vintage</groupId>
                    <artifactId>junit-vintage-engine</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
        </dependency>

        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>fastjson</artifactId>
            <version>1.2.73</version>
        </dependency>

    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

4.2 Data configuration information: application.properties

#配置数据库连接信息
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
spring.datasource.url=jdbc:mysql://localhost:3306/student?characterEncoding=utf-8&serverTimezone=UTC
spring.datasource.username=root
spring.datasource.password=root

#数据库连接池

#mapper映射
mybatis.type-aliases-package=com.example.studentsys.entiy
mybatis.mapper-locations=classpath:mapper/*.xml

4.3 Entity class: User.java

package com.example.studentsys.entiy;

public class User {
    private Integer id;
    private String username;
    private String password;

    public void setId(Integer id){
        this.id = id;
    }
    public Integer getId(){
        return id;
    }
    public void setUsername(String username){
        this.username = username;
    }
    public String getUsername(){
        return username;
    }
    public void setPassword(String password){
        this.password = password;
    }
    public String getPassword(){
        return password;
    }
}

4.4 mapper interface: UserMapper.java

package com.example.studentsys.mapper;

import com.example.studentsys.entiy.User;
import org.apache.ibatis.annotations.Mapper;
import org.springframework.stereotype.Repository;

import java.util.List;

//@Repository将类标识为bean
@Repository
@Mapper
public interface UserMapper {
    List<User> findAll();
    User findByName(String name);
    String findPswByName(String UserName);
    void save(User user);
}

4.5 UserMapper.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<!--xmlns="http://mybatis.org/schema/mybatis-mapper"-->
<mapper namespace="com.example.studentsys.mapper.UserMapper">
    <select id="findAll" resultType="User">
        select * from User
    </select>
    <select id="findByName" resultType="User">
        select * from User where username=#{username}
    </select>
    <select id="findPswByName" resultType="String">
        select password from user where username = #{username}
    </select>
    <insert id="save">
        insert into user(username,password) value (#{username},#{password})
    </insert>
</mapper>

4.6 service class: UserService.java

package com.example.studentsys.service;

import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.JSONObject;
import com.example.studentsys.entiy.User;
import com.example.studentsys.mapper.UserMapper;
import org.apache.ibatis.jdbc.Null;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.Collections;
import java.util.List;

@Service
public class UserService {

    //该注解可以对类成员变量、方法以及构造函数进行标注，完成自动装配工作
    @Autowired
    UserMapper userMapper;

    public String login(User user){
        //登录逻辑函数
        try{
            User userExistN = userMapper.findByName(user.getUsername());
            if(userExistN!=null){
                String userExistP = userMapper.findPswByName(user.getUsername());
                if(userExistP.equals(user.getPassword())){
                    return user.getUsername()+"登录成功，欢迎您!";
                }else {
                    return "登录失败，密码错误!";
                }
            }else {
                return "登录失败，用户不存在!";
            }
        }catch (Exception e){
            e.printStackTrace();
            return e.getMessage();
        }
    }

    public String regist(User user){
        //注册逻辑函数
        try {
            User userExist = userMapper.findByName(user.getUsername());
            if (user.getUsername().equals("")){
                return "用户名不能为空";
            }else if (user.getPassword().equals("")){
                return "密码不能为空";
            }else if (userExist!=null){
                return "账户已经存在";
            }else{
                userMapper.save(user);
                return "注册成功";
            }
        }catch (Exception e){
            e.printStackTrace();
            return e.getMessage();
        }

    }

    public List<User> findAll(){
        List<User> list = userMapper.findAll();
        return list;
    }

}

4.7 Control class: UserController.java

package com.example.studentsys.controller;

import com.example.studentsys.entiy.User;
import com.example.studentsys.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;

import java.util.List;

@RestController
@RequestMapping("/user")
public class UserController {
    @Autowired
    UserService userService;

    @PostMapping("/login")
    public String login(User user){
        return userService.login(user);
    }

    @PostMapping("/regist")
    public String regist(User user){
        return userService.regist(user);
    }

    /**
     * 解决查询数据库中文出现乱码问题
     * @return
     */
    @RequestMapping(value = "/alluser", method = RequestMethod.GET, produces = "application/json;charset=UTF-8")
    public List<User> findAll(){
        return userService.findAll();
    }
}

5. Run the project

http://localhost:8080/user/login.html enter the login page

http://localhost:8080/user/regist.html Enter the registration page

http://localhost:8080/user/alluser View all current user information

6. Summary

MySQL common management commands

@RestController annotation

Business logic:

Mapper is responsible for connecting data and performing related CRUD operations

Service uses Mapper to complete the business logic of login and registration

Controller receives browser access and provides login and registration services with the help of Service

SpringBoot learning to realize the login and registration function

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