SpringBoot学习之实现登录注册功能

1、系统目录结构

2、创建数据库

数据库名称:student，数据表:user，创建命令如下：

//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、创建前端页面

3.1 登录页面：login.html

    
    


    

        用户名：
        密码：
        
        
    

3.2 注册页面：regist.html

    
    


    

        用户名：
        密码：
        
        

    

 4、Java代码

4.1 pom树

    4.0.0
    
        org.springframework.boot
        spring-boot-starter-parent
        2.3.4.RELEASE
         
    
    com.example
    studentsys
    0.0.1-SNAPSHOT
    studentsys
    Demo project for Spring Boot

    
        11
    

    
        
            org.springframework.boot
            spring-boot-starter-jdbc
        
        
            org.springframework.boot
            spring-boot-starter-web
        
        
            org.mybatis.spring.boot
            mybatis-spring-boot-starter
            2.1.3
        

        
            mysql
            mysql-connector-java
            runtime
        
        
            org.springframework.boot
            spring-boot-starter-test
            test
            
                
                    org.junit.vintage
                    junit-vintage-engine
                
            
        
        
            org.projectlombok
            lombok
        

        
            com.alibaba
            fastjson
            1.2.73
        

    

    
        
            
                org.springframework.boot
                spring-boot-maven-plugin
            
        
    

4.2 数据配置信息：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 实体类：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接口：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 findAll();
    User findByName(String name);
    String findPswByName(String UserName);
    void save(User user);
}

4.5  UserMapper.xml

    
        select * from User
    
    
        select * from User where username=#{username}
    
    
        select password from user where username = #{username}
    
    
        insert into user(username,password) value (#{username},#{password})
    

4.6 service类：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 findAll(){
        List list = userMapper.findAll();
        return list;
    }

}

4.7  控制类：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 findAll(){
        return userService.findAll();
    }
}

5、运行项目

http://localhost:8080/login.html 进入到登录页面

 http://localhost:8080/regist.html 进入到注册页面

 http://localhost:8080/user/alluser 查看当前所有用户信息

6、总结

MySQL常见管理命令

@RestController注解

业务逻辑：

Mapper负责连接数据并进行相关的CRUD操作

Service借助Mapper来完成登录注册的业务逻辑

Controller接待浏览器访问，借助Service提供登录注册服务