第三⼗⼀章 项⽬实战之打通Myabtis连接Mysql开发视频列表

其他 2023-07-11 17:29:49 阅读次数: 0
第 1 集 线上课堂实战之 Mybaits 打通 Mysql 数据库

简介：配置Mybatis连接Mysql数据库 

添加数据库配置 

server.port=8081
#============================== 数据库相关配置
========================================
spring.datasource.driver-class-name =com.mysql.cj.jdbc.Driver
spring.datasource.url=jdbc:mysql://127.0.0.1:3306/online_xdclass?
useUnicode=true&characterEncoding=utf-8&useSSL=false
spring.datasource.username=root
spring.datasource.password=xdclass.net
# 使⽤阿⾥巴巴 druid 数据源，默认使⽤⾃带的
#spring.datasource.type =com.alibaba.druid.pool.DruidDataSource
# 开启控制台打印 sql
mybatis.configuration.log-impl=org.apache.ibatis.logging.stdout.StdOutImpl
# mybatis 下划线转驼峰配置 , 两者都可以
#mybatis.configuration.mapUnderscoreToCamelCase=true
mybatis.configuration.map-underscore-to-camel-case=true
# 配置扫描
mybatis.mapper-locations=classpath:mapper/*.xml
# 配置 xml 的结果别名
mybatis.type-aliases-package=net.xdclass.online_xdclass.domain

创建Video相关类 

创建VideoMapper.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.xjclass.oncline_xjclass.Mapper.VideoMapper">

</mapper>
配置扫描 mapper 路径 
@SpringBootApplication
@MapperScan("net.xdclass.online_xdclass.mapper")
public class OnlineXdclassApplication {
 public static void main(String[] args) {
 SpringApplication.run(OnlineXdclassApplication.class, args);
 }
}

第2集 ⼩滴课堂实战之视频列表接⼝开发+API权限路径规划

简介：开发视频列表JSON接⼝ 

  • postman调试接⼝ 
    • 浏览器如果要⽀持 json 格化，需要安装⾕歌插件，但是⽹络问题直接安装不了，推荐使⽤插件
  • 开发视频列表接⼝
    开发 jsondata ⼯具类
    规划 api 权限路径
          /api/v1/pub/AA/BB 这个是不需要登录
          /api/v1/pri/AA/BB 这个是需要登录

    第3集 ⼩滴课堂实战之dev-tool 实现IDEA项⽬热部署

    简介：使⽤dev-tool实现热部署

        步骤
                pom⽂件添加依赖包
<dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-devtools</artifactId>
        <optional>true</optional>
</dependency>
<build>
        <plugins>
                <plugin>
                        <groupId>org.springframework.boot</groupId>
                        <artifactId>spring-boot-maven-plugin</artifactId>
                        <configuration>
                                <fork>true</fork><!--必须添加这个配置-->
                        </configuration>
                </plugin>
        </plugins>
</build>

 详细步骤请看第五章！！！

第4集 ⼩滴课堂实战之⾸⻚banner轮播图和视频详情接⼝开发

简介：⾸⻚banner轮播图接⼝开发 

开发轮播列表接⼝

VideoBanner实体类：

public class VideoBanner {
    private int id;
    private String url;
    private String img;
    private Date createTime;
    private int weight; //权重越大，越靠前;

    //toString() set() get方法
}

 Controller:

@RestController
@RequestMapping("api/v1/pub/index")
public class IndexController {
    @Autowired
    private VideoBannerService videoBannerService;
    @RequestMapping("findVideoBannerList")
    public JsonData VideoBannerList(){
        List<VideoBanner> videoBannerList = videoBannerService.findVideoBannerList();
        return JsonData.JsonDataBuild(videoBannerList);
    }
}

Service：

public interface VideoBannerService {
    /**
     * 按权重的从大到小的顺序查找轮播图
     * @return
     */
    List<VideoBanner> findVideoBannerList();
}
@Service
public class VideoBannerServiceImpl implements VideoBannerService {
    @Autowired
    public VideoBannerMapper videoBannerMapperr;
    @Override
    public List<VideoBanner> findVideoBannerList() {

        return videoBannerMapperr.findVideoBannerList();
    }
}

Mapper接口：

@Repository
public interface VideoBannerMapper {
    List<VideoBanner> findVideoBannerList();
}

启动类：

@SpringBootApplication
@MapperScan("com.xjclass.oncline_xjclass.Mapper")
public class OnclineXjclassApplication {

	public static void main(String[] args) {
		SpringApplication.run(OnclineXjclassApplication.class, args);
	}

}

Mapper.xml文件：

<?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.xjclass.oncline_xjclass.Mapper.VideoBannerMapper">
    <resultMap id="VideoBannerResultMap" type="videoBanner">
        <id column="id" property="id" jdbcType="INTEGER"></id>
        <result column="create_time" property="createTime" jdbcType="TIMESTAMP"></result>
    </resultMap>
    <select id="findVideoBannerList" resultMap="VideoBannerResultMap">
        select * from video_banner order by weight desc
    </select>

</mapper>

运行结果：

 第5集 ⼩滴课堂实战之视频详情接⼝开发-三表关联查询映射

 简介：视频详情接⼝，多表关联开发

  • 修改Video-Chapter POJO类, 增加属性（不使⽤DTO）
  • 定义ResultMap
  • 调试接⼝数据

controller:

  @PostMapping("findVideoDetailsByVideoId")
    public JsonData findVideoDetailsByVideoId(@RequestBody Map<String,Object> params){
        Integer videoId = (Integer)params.get("videoId");
        Video videoDetailList = videoService.findVideoDetailsByVideoId(videoId);
        return JsonData.JsonDataBuild(videoDetailList);
    }

Service:

Video findVideoDetailsByVideoId(int videoId);
@Service
public class VideoServiceImpl implements VideoService {
    @Autowired
    private VideoMapper videoMapper;
  

    @Override
    public Video findVideoDetailsByVideoId(int videoId) {
       return videoMapper.findVideoDetailsByVideoId(videoId);
    }
}

Mapper:

 //三表查询，查询指定视频的详细信息
    Video findVideoDetailsByVideoId(@Param("videoId") int videoId);

启动类：

@SpringBootApplication
@MapperScan("com.xjclass.oncline_xjclass.Mapper")
public class OnclineXjclassApplication {

	public static void main(String[] args) {
		SpringApplication.run(OnclineXjclassApplication.class, args);
	}

}

Mapper.xml文件：

<?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.xjclass.oncline_xjclass.Mapper.VideoMapper">

    <!--三表关联查询-->
    <resultMap id="VideoDetailResultMap" type="video">
        <id column="id" property="id" jdbcType="INTEGER"></id>
        <result column="title" property="title" jdbcType="VARCHAR"/>
        <result column="summary" property="summary" jdbcType="VARCHAR"/>
        <result column="cover_img" property="CoverImg" jdbcType="VARCHAR"/>
        <result column="create_time" property="CreateTime" jdbcType="TIMESTAMP"/>
        <result column="c_id" property="Cid" jdbcType="INTEGER"/>
        <result column="point" property="point" jdbcType="DOUBLE"/>

        <collection property="chapters" ofType="chapter">
            <id column="chapter_id" jdbcType="INTEGER" property="id"></id>
            <result column="chapter_title" property="title" jdbcType="VARCHAR"/>
            <result column="ordered" property="ordered" jdbcType="INTEGER"/>
            <result column="chapter_create_time" property="createTime" jdbcType="TIMESTAMP"/>

            <collection property="episodes" ofType="episode">
                <id column="episode_id" property="id" jdbcType="INTEGER"></id>
                <result column="episode_title" property="title" jdbcType="VARCHAR"/>
                <result column="num" property="num" jdbcType="INTEGER"/>
                <result column="play_url" property="playUrl" jdbcType="VARCHAR"/>
                <result column="free" property="free" jdbcType="INTEGER"/>
                <result column="cover_img" property="coverImg" jdbcType="VARCHAR"/>
                <result column="create_time" property="createTime" jdbcType="TIMESTAMP"/>

            </collection>
        </collection>

    </resultMap>

    <select id="findVideoDetailsByVideoId" resultMap="VideoDetailResultMap">
    SELECT
  v.id,v.title,v.summary,v.cover_img,v.price,v.point,v.create_time,
  c.id as chapter_id,c.title as chapter_title,
  c.ordered,c.create_time as chapter_create_time,
  e.id as episode_id,e.num,e.title as episode_title,e.ordered as episode_ordered,
  e.play_url,e.free,e.create_time as episode_create_time
  from video v
  LEFT JOIN chapter c on v.id = c.video_id
  LEFT JOIN episode e on c.id = e.chapter_id

where v.id = #{videoId}
ORDER BY c.ordered,e.num asc;
    </select>
</mapper>

        运行结果：

 第6集 ⼩滴课堂实战之⾃定义异常开发和配置

简介：开发⾃定义异常和配置
⾃定义异常 继承 RuntimeException 
public class XJException  extends RuntimeException{
    private Integer code; //状态码

    private String msg;  //错误提示内容

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

    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;
    }
}

 开发异常处理器ExceptionHandle

/**
 * 处理类
 */
@ControllerAdvice
public class CustomExceptionhandle {

    public final static Logger logger = LoggerFactory.getLogger(CustomExceptionhandle.class);
    //返回给用户错误信息
    @ExceptionHandler(value = Exception.class)
    @ResponseBody
    public JsonData handle(Exception e) {
        logger.error("[ 系统异常 ]{}",e); //打印
        if (e instanceof XJException){
           XJException exception =  (XJException) e;
            return JsonData.JsonDataError("",exception.getCode(),exception.getMsg());
        }else{
            return JsonData.JsonDataError("",-500,"全局异常，未知错误");
        }
    }
}

科普以下@ControllerAdvice注解:@ControllerAdvice 就是 @Controller 的增强版。@ControllerAdvice 主要用来处理全局数据，一般搭配 @ExceptionHandler、@ModelAttribute、@InitBinder使用，在三个应用场景中使用：全局异常处理、全局数据绑定和全局数据预处理。
@ControllerAdvice是@Component注解的一个延伸注解，Spring会自动扫描并能检测到被@ControllerAdvice所标注的类。

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