springboot整合sqllite

Spring boot + Mybatis + SQLite 搭建blog API

Spring boot + Mybatis + SQLite 搭建blog API#

一、准备环境#

• jdk1.8
• Maven仓库
• IDEA
• SQLite

二、创建一个SpringBoot项目#

在此我就不再演示如何创建SpringBoot项目了，需要的请看【 码出精彩人生】这位大佬的博客

使用IDEA创建一个springboot项目

三、在pom.xml文件中添加所需要的依赖jar#

使用sqlite数据库需要引入sqlite-jdbc.jar包#

Copy<!-- SQLite 驱动 -->
<dependency>
    <groupId>org.xerial</groupId>
    <artifactId>sqlite-jdbc</artifactId>
    <version>3.21.0.1</version>
</dependency>

pom.xml文件依赖如下#

Copy<dependencies>
	<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>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>
    <!-- SQLite 驱动 -->
    <dependency>
        <groupId>org.xerial</groupId>
        <artifactId>sqlite-jdbc</artifactId>
        <version>3.21.0.1</version>
    </dependency>
    <dependency>
        <groupId>org.projectlombok</groupId>
        <artifactId>lombok</artifactId>
        <version>1.16.22</version>
    </dependency>
</dependencies>

四、创建sqlite数据库#

1、在项目的根目录下创建文件 blog-db.sqlite (名字随便起)#

2、然后在IDEA右边边上有一个Database，点击创建SQLite数据库#

3、File–>>选择第一步创建的 blog-db.sqlite ,然后点击Test Connection 测试是否连接成功#

4、创建 d_user 表#

(1) 控制台创建表

拷贝下面创建表语句，执行即可创建表

Copycreate table d_users
(
    id        int
        constraint "d-users_pk"
            primary key,
    username  text not null,
    password  text not null,
    start     int default 1 not null,
    foundTime text
);

（2）手动创建

五、一切准备就绪开始写业务。#

1、添加配置文件application.yaml#

把创建项目生成的.properties配置文件删除，创建一个 application.yaml，配置文件放在 resources 目录下

Copyserver:
  port: 8989 # 端口号
spring:
  datasource:
    url: jdbc:sqlite:D:/Software/PycharmProjects/d-blog/blog-db.sqlite # 创建的sqlite数据库所在路径
    username: # 因为没有用户名和密码，所以这两个参数就没有值
    password:
    driver-class-name: org.sqlite.JDBC # sqlite驱动

# mybatis配置
mybatis:
  mapper-locations: classpath:mybatis/mapper/*Mapper.xml # 配置mapper.xml文件路径
  type-aliases-package: com.desire.entity # 实体类包名
# mybatis 打印SQL, 配置后就会在控制台打印执行的SQL语句
logging:
  level:
    com.desire.dao: debug

2、根据数据库表创建实体类–UserEntity.java#

Copypackage com.desire.entity;

import lombok.Getter;
import lombok.Setter;
import lombok.ToString;

@Getter
@Setter
@ToString
public class UserEntity {
    private int id;
    private String userName;
    private String password;
    private int start;
    private String foundTime;
}

3、在resources/mybatis/mapper中创建表的映射–UserMapper.xml#

Copy<?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">
<mapper namespace="com.desire.dao.IUserDao">

    <resultMap id="BaseResultMap" type="com.desire.entity.UserEntity">
        <result column="id" jdbcType="INTEGER" property="id" />
        <result column="userName" jdbcType="VARCHAR" property="userName" />
        <result column="password" jdbcType="VARCHAR" property="password" />
        <result column="start" jdbcType="INTEGER" property="start" />
        <result column="foundTime" jdbcType="VARCHAR" property="foundTime" />
    </resultMap>

    <select id="findUserById" resultType="com.desire.entity.UserEntity">
        select * from d_users where id = #{id}
    </select>
    <select id="findUserAll" resultMap="BaseResultMap" resultType="com.desire.entity.UserEntity">
        select * from d_users
    </select>
</mapper>

4、创建表数据库访问层接口–IUserDao.java#

Copypackage com.desire.dao;

import com.desire.entity.UserEntity;
import org.apache.ibatis.annotations.Mapper;

import java.util.List;

/**
 * (D_Users)表数据库访问层
 */
@Mapper
public interface IUserDao {
    UserEntity findUserById(int id);
    List<UserEntity> findUserAll();
}

5、创建表服务接口–IUserService.java#

Copypackage com.desire.service;

import com.desire.entity.UserEntity;

import java.util.List;

/**
 * (D_Users)表服务接口
 */
public interface IUserService {

    UserEntity findUserById(int id);

    List<UserEntity> findUserAll();
}

6、创建表服务实现类–UserServiceImpl.java#

Copypackage com.desire.service.impl;

import com.desire.dao.IUserDao;
import com.desire.entity.UserEntity;
import com.desire.service.IUserService;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;
import java.util.List;

/**
 * (D_Users)表服务实现类
 */
@Service
public class UserServiceImpl implements IUserService {
    @Resource
    private IUserDao IUserDao;

    @Override
    public UserEntity findUserById(int id) {
        return IUserDao.findUserById(id);
    }

    @Override
    public List<UserEntity> findUserAll() {
        return IUserDao.findUserAll();
    }
}

7、创建表控制层Controller–UserController.java#

Copypackage com.desire.controller;

import com.desire.common.DateUtil;
import com.desire.common.Result;
import com.desire.common.ResultUtil;
import com.desire.entity.UserEntity;
import com.desire.service.IUserService;
import org.springframework.web.bind.annotation.*;

import javax.annotation.Resource;
import java.util.List;

import static com.desire.common.ResultEnum.*;

/**
 * (D_Users)表控制层
 */
@RestController
@RequestMapping("/user")
public class UserController {
    /**
     * 服务对象
     */
    @Resource
    private IUserService userService;

    @RequestMapping("getUser/{id}")
    public Result<Object> getUser(@PathVariable int id) {
        UserEntity user = userService.findUserById(id);
        if (user != null) {
            user.setFoundTime(DateUtil.timeStamp2Date(user.getFoundTime(), null));
            return ResultUtil.success(SUCCESS, user);
        } else {
            return ResultUtil.error(USER_NOT_FOND);
        }

    }

    @RequestMapping("getUsers")
    public Result<Object> getUsers() {
        List<UserEntity> users = userService.findUserAll();
        for (UserEntity user : users) {
            user.setFoundTime(DateUtil.timeStamp2Date(user.getFoundTime(), null));
        }
        return ResultUtil.success(SUCCESS, users);
    }
}

8、规范化封装统一返回数据格式#

1）定义http请求返回的最外层对象，封装返回数据的统一格式 –Result.java

Copypackage com.desire.common;

import lombok.Getter;
import lombok.Setter;

/**
 * http请求返回的最外层对象
 * @param <T>
 */
@Getter
@Setter
public class Result<T> {
    /**
     * 错误码.
     */
    private Integer code;

    /**
     * 提示信息.
     */
    private String msg;

    /**
     * 具体的内容.
     */
    private T data;
}

2) 为了统一管理返回数据结果code和message，新建一个枚举类ResultEnum.java

Copypackage com.desire.common;
import lombok.Getter;

@Getter
public enum ResultEnum {
    UNKONW_ERROR(1001, "未知错误"),
    SUCCESS(200, "成功")
    ;

    private Integer code;

    private String msg;

    ResultEnum(Integer code, String msg) {
        this.code = code;
        this.msg = msg;
    }
}

3) 为了防止多次出现new Result()的代码造成冗余，增加一个工具类ResultUtil.java

Copypackage com.desire.common;

/**
 * 为了避免出现代码冗余情况，应该增加工具类，封装请求失败和成功时候的方法，这里可使用静态方法
 */
public class ResultUtil {
    public static Result<Object> success(ResultEnum resultEnum, Object object) {
        Result<Object> result = new Result<>();
        result.setCode(resultEnum.getCode());
        result.setMsg(resultEnum.getMsg());
        result.setData(object);
        return result;
    }

    public static Result<Object> error(ResultEnum resultEnum) {
        Result<Object> result = new Result<>();
        result.setCode(resultEnum.getCode());
        result.setMsg(resultEnum.getMsg());
        return result;
    }
}

六、启动项目，验证写的是否正确–成功#