【springboot】—— 后端Springboot项目开发

后端Springboot项目开发

步骤1 先创建数据库，并在下面创建一个user表，插入数据，sql如下：

CREATE TABLE `user` (
 `id` int(11) NOT NULL AUTO_INCREMENT COMMENT 'ID',
 `email` varchar(255) NOT NULL COMMENT '邮箱',
 `password` varchar(255) NOT NULL COMMENT '密码',
 `username` varchar(255) NOT NULL COMMENT '姓名',
 PRIMARY KEY (`id`),
 UNIQUE KEY `email` (`email`) USING BTREE
) ENGINE=InnoDB AUTO_INCREMENT=2 DEFAULT CHARSET=utf8;


INSERT INTO `user` VALUES ('1', '1@qq.com', '123456', '张三');
INSERT INTO `user` VALUES ('2', '2@qq.com', '234567', '李四');
INSERT INTO `user` VALUES ('3', '3@qq.com', '345678', '王五');

步骤2 创建一个springboot项目，然后在pom文件中引入相关依赖：

<?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>2.7.10</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.example</groupId>
    <artifactId>zht_backend</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>zht_backend</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-thymeleaf</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <!-- Spring Boot Mybatis 依赖 -->
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>1.3.0</version>
        </dependency>
        <!-- MySQL 连接驱动依赖 -->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.31</version>
        </dependency>

        <!--io工具类-->
        <dependency>
            <groupId>commons-io</groupId>
            <artifactId>commons-io</artifactId>
            <version>2.5</version>
        </dependency>
    </dependencies>
    <build>
        <plugins>
            <!--运用SpringBoot 插件  使用spring-boot-devtools模块的应用,当classpath中的文件有改变时，会自动重启！-->
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <configuration>
                    <fork>true</fork>
                </configuration>
            </plugin>
        </plugins>
    </build>

</project>

步骤3 配置文件application.yml，内容如下：

server:
  port: 8080
spring:
  datasource:
    driver-class-name: com.mysql.cj.jdbc.Driver
    url: jdbc:mysql://localhost:3306/ceshi?serverTimezone=GMT%2b8
    username: root
    password: root
  redis:
    host: 127.0.0.1
    port: 6379
  servlet:
    multipart:
      max-file-size: 100MB
      max-request-size: 100MB
mybatis:
  mapper-locations: classpath:mapper/*.xml  #扫描所有mybatis的xml文件
#  configuration:
#    log-impl: org.apache.ibatis.logging.stdout.StdOutImpl
mybatis-plus:
  configuration:
    log-impl: org.apache.ibatis.logging.stdout.StdOutImpl

files:
  upload:
    path: D:/files/
#    path: /home/files/

步骤4 开始编写核心逻辑代码，新建一个User.java实体类，代码如下：

package com.example.zht_backend.bean;

/**
 * 功能描述
 *
 * @author: 衍生星球
 * @date: 2023年06月26日 8:37
 */

public class User {
    private long id;
    private String email;
    private String password;
    private String username;

    public long getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    public String getEmail() {
        return email;
    }
    public void setEmail(String email) {
        this.email = email;
    }
    public String getPassword() {
        return password;
    }
    public void setPassword(String password) {
        this.password = password;
    }
    public String getUsername() {
        return username;
    }
    public void setUsername(String username) {
        this.username = username;
    }
}

然后再新建一个dao文件：

package com.example.zht_backend.dao;

import com.example.zht_backend.bean.User;
import org.apache.ibatis.annotations.*;
import org.springframework.data.repository.query.Param;

import java.util.List;

@Mapper
public interface UserDao {
    /**
     * 新增数据
     */
    @Insert("insert into user(id,email,password,username) values (#{id},#{email},#{password},#{username})")
    void addUser(User user);

    /**
     * 修改数据
     */
    @Update("update user set username=#{username},password=#{password} where id=#{id}")
    void updateUser(User user);

    /**
     * 删除数据
     */
    @Delete("delete from user where id=#{id}")
    void deleteUser(int id);

    /**
     * 根据查询数据
     *
     */
    @Select("select id,email,password,username from user where username=#{userName}")
    User findByName(@Param("userName") String userName);

    /**
     * 查询所有数据
     */
    @Select("select id,email,password,username FROM user")
    List<User> findAll();
}

然后就是service和UserServiceImpl文件：

userservice:

package com.example.zht_backend.service;

import com.example.zht_backend.bean.User;

import java.util.List;

public interface UserService {
    /**
     * 新增用户
     * @param user
     * @return
     */
    boolean addUser(User user);

    /**
     * 修改用户
     * @param user
     * @return
     */
    boolean updateUser(User user);


    /**
     * 删除用户
     * @param id
     * @return
     */
    boolean deleteUser(int id);

    /**
     * 根据名字查询用户信息
     * @param userName
     */
    User findUserByName(String userName);


    /**
     * 查询所有数据
     * @return
     */
    List<User> findAll();
}

UserServiceImpl文件：

package com.example.zht_backend.service.impl;

import com.example.zht_backend.bean.User;
import com.example.zht_backend.dao.UserDao;
import com.example.zht_backend.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.List;

/**
 * 功能描述
 *
 * @author: 衍生星球
 * @date: 2023年06月26日 8:45
 */
@Service
public class UserServiceImpl implements UserService {
    @Autowired
    private UserDao userDao;

    @Override
    public boolean addUser(User user) {
        boolean flag=false;
        try {
            userDao.addUser(user);
            flag=true;
        }catch (Exception e){
            e.printStackTrace();
        }
            return flag;
    }

    @Override
    public boolean updateUser(User user) {
        boolean flag=false;
        try{
            userDao.updateUser(user);
            flag=true;
        }catch(Exception e){
            e.printStackTrace();
        }
        return flag;
    }

    @Override
    public boolean deleteUser(int id) {
        boolean flag=false;
        try{
            userDao.deleteUser(id);
            flag=true;
        }catch(Exception e){
            e.printStackTrace();
        }
        return flag;
    }

    @Override
    public User findUserByName(String userName) {
        return userDao.findByName(userName);
    }

    @Override
    public List<User> findAll() {
        return userDao.findAll();
    }
}

最后就是controller文件：

package com.example.zht_backend.controller;

import com.example.zht_backend.bean.User;
import com.example.zht_backend.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;

import java.util.List;

/**
 * 功能描述
 *
 * @author: 衍生星球
 * @date: 2023年06月26日 8:52
 */
@RestController
@RequestMapping(value = "/do/user")
public class UserController {
    @Autowired
    private UserService userService;

    @RequestMapping(value = "/user", method = RequestMethod.POST)
    public boolean addUser(@RequestBody User user) {
        System.out.println("新增数据：");
        return userService.addUser(user);
    }

    @RequestMapping(value = "/user", method = RequestMethod.PUT)
    public boolean updateUser(@RequestBody User user) {
        System.out.println("更新数据：");
        return userService.updateUser(user);
    }

    @RequestMapping(value = "/user", method = RequestMethod.DELETE)
    public boolean delete(@RequestParam(value = "id", required = true) int Id) {
        System.out.println("删除数据：");
        return userService.deleteUser(Id);
    }


    @RequestMapping(value = "/user", method = RequestMethod.GET)
    public User findByUserName(@RequestParam(value = "userName", required = true) String userName) {
        System.out.println("查询数据：");
        return userService.findUserByName(userName);
    }

    @RequestMapping(value = "/userAll", method = RequestMethod.GET)
    public List<User> findByUserAge() {
        System.out.println("查询所有数据:");
        return userService.findAll();
    }
}