Spring boot + Mybatis + SQLite 搭建blog API

Spring boot + Mybatis + SQLite 搭建blog API

一、准备环境

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

<!-- 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

<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

Spring boot + Mybatis + SQLite 搭建blog API

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

Spring boot + Mybatis + SQLite 搭建blog API

4、创建 d_user 表

(1) 控制台创建表

Spring boot + Mybatis + SQLite 搭建blog API

拷贝下面创建表语句,执行即可创建表

create 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

Spring boot + Mybatis + SQLite 搭建blog API

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

server:
  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.mapper: debug

2、根据数据库表创建实体类--UserEntity.java

package 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--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">
<mapper namespace="com.desire.mapper.UserMapper">

    <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mapper接口--UserMapper.java

package com.desire.mapper;

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

import java.util.List;

@Mapper
public interface UserMapper {
    UserEntity findUserById(int id);
    List<UserEntity> findUserAll();
}

5、创建service实现mapper接口--UserService.java

package com.desire.service;

import com.desire.entity.UserEntity;
import com.desire.mapper.UserMapper;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.List;

@Service
public class UserService implements UserMapper {
    @Autowired
    private UserMapper userMapper;

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

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

6、创建Controller--UserController.java

package com.desire.controller;

import com.desire.common.Result;
import com.desire.common.ResultUtil;
import com.desire.entity.UserEntity;
import com.desire.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.bind.annotation.RestController;

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

    @RequestMapping("getUser/{id}")
    public Result<UserEntity> getUser(@PathVariable int id) {
        return ResultUtil.success(userService.findUserById(id));
    }

    @RequestMapping("getUsers")
    public Result<UserEntity> getUsers() {
        return ResultUtil.success(userService.findUserAll());
    }
}

7、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
package com.desire.common;

/**
 * http请求返回的最外层对象
 * @param <T>
 */
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;

    public Integer getCode() {
        return code;
    }

    public void setCode(Integer code) {
        this.code = code;
    }

    public String getMsg() {
        return msg;
    }

    public void setMsg(String msg) {
        this.msg = msg;
    }

    public T getData() {
        return data;
    }

    public void setData(T data) {
        this.data = 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
package com.desire.common;

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;
    }

    public Integer getCode() {
        return code;
    }

    public String getMsg() {
        return 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
package com.desire.common;

/**
 * 为了避免上面出现的代码冗余情况,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 success(Object object) {
        Result result = new Result();
        result.setCode(ResultEnum.SUCCESS.getCode());
        result.setMsg(ResultEnum.SUCCESS.getMsg());
        result.setData(object);
        return result;
    }

    public static Result success() {
        return success(null);
    }

    public static Result error(Integer code, String msg) {
        Result result = new Result();
        result.setCode(code);
        result.setMsg(msg);
        return result;
    }
}

六、启动项目,验证写的是否正确--成功

Spring boot + Mybatis + SQLite 搭建blog API

Spring boot + Mybatis + SQLite 搭建blog API

七、写在最后

这个例子只实现了两个接口

最近在写一个博客相关的项目,前端vue部分已经完成(感觉写的很low),不过还有待继续改进,我也在继续学习vue,所用接口,用的是json server 做的服务。

有兴趣的可以看下,提点意见,【personal_blog

这个SpringBoot项目就是我做的博客的接口服务,后续要把前端中的json server换成真实的接口。持续更新中,写的不好请给我提些建议。感谢看到最后。

Spring boot + Mybatis + SQLite 搭建blog API

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