homepage 第三期：服务模块的通用模块开发及数据表的相关操作

1.建立服务模块，他同样是一个父模块，在 pom 文件中的打包方式处仍然是 pom，并且由于他是一个父模块，所以不需要 src 目录，删除。

2.建立服务模块的自模块：通用模块，用来写 course 服务和 user 服务可能用到的代码
在他的 pom 文件中添加相关依赖（打包方式为 jar）

<dependencies>
        <!--  JSON处理工具  -->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>fastjson</artifactId>
            <version>1.2.31</version>
        </dependency>

        <!--  apache提供的工具类  -->
        <dependency>
            <groupId>commons-codec</groupId>
            <artifactId>commons-codec</artifactId>
            <version>1.9</version>
        </dependency>

3.在通用模块中编写相关服务
@1.完成 courseInfo 类

package cn.chenforcode.homepage;

import lombok.AllArgsConstructor;
import lombok.Builder;
import lombok.Data;
import lombok.NoArgsConstructor;

/**
 * @author <a href="http://www.chenforcode.cn">PKUCoder</a>
 * @date 2019/11/11 12:57 上午
 * @description 基本课程信息
 */
@Data
@Builder
@NoArgsConstructor
@AllArgsConstructor
public class CourseInfo {
    private Long id;
    private String courseName;
    private String courseType;
    private String courseIcon;
    private String courseIntro;

    public static CourseInfo invalid() {
        return new CourseInfo(-1L, "", "", "", "");
    }
}

@2.完成 userInfo 类

package cn.chenforcode.homepage;

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

/**
 * @author <a href="http://www.chenforcode.cn">PKUCoder</a>
 * @date 2019/11/11 12:53 上午
 * @description 基本的用户信息
 */
@Data
@NoArgsConstructor
@AllArgsConstructor
public class UserInfo {
    private Long id;
    private String username;
    private String email;

    public static UserInfo invalid() {
        return new UserInfo(-1L, "", "");
    }
}

@3.完成 courseInfoRequest 类

package cn.chenforcode.homepage;

import java.util.List;

/**
 * @author <a href="http://www.chenforcode.cn">PKUCoder</a>
 * @date 2019/11/11 1:01 上午
 * @description 课程信息请求对象
 */
public class CourseInfosRequest {
    private List<Long> ids;
}

4.建立课程服务模块，完成 pom 文件，注意这里是一个 web 服务，所以需要加入 web 相关的依赖

<?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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <parent>
        <artifactId>imooc-homepage-service</artifactId>
        <groupId>cn.chenforcode.homepage</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>homepage-course</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>jar</packaging>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.18</version>
            <scope>runtime</scope>
        </dependency>

        <!--  通用模块  -->
        <dependency>
            <groupId>cn.chenforcode.homepage</groupId>
            <artifactId>homepage-common</artifactId>
            <version>1.0-SNAPSHOT</version>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>
</project>

5.编写启动类，这里的 @enableJpaAuditing 的作用是自动管理每一条数据的 createtime 和 updatetime 不需要自己管理

package cn.chenforcode.homepage;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
import org.springframework.data.jpa.repository.config.EnableJpaAuditing;

/**
 * @author <a href="http://www.chenforcode.cn">PKUCoder</a>
 * @date 2019/11/11 3:55 下午
 * @description homepageCourse服务启动类
 */
@EnableJpaAuditing
@EnableEurekaClient
@SpringBootApplication
public class HomepageCourseApplication {
    public static void main(String[] args) {
        SpringApplication.run(HomepageCourseApplication.class, args);
    }
}

6.完成配置文件

server:
  port: 7001
  servlet:
    context-path: /homepage-course
spring:
  application:
    name: eureka-client-homepege-course
  jpa:
    hibernate:
      ddl-auto: none
    show-sql: true
    properties:
      hibernate.format_sql: true
    open-in-view: false
  datasource:
    url: jdbc:mysql://127.0.0.1:3306/imooc_homepage_sc?autoReconnect=true&useUnicode=true&characterEncoding=utf8&useSSL=false
    username: root
    password: yourpassword
    driver-class-name: com.mysql.cj.jdbc.Driver
    tomcat:
      max-active: 4
      min-idle: 2
      initial-size: 2
eureka:
  client:
    service-url:
      #如果是一个集群，那么把所有的eureka的地址都写到这
      defaultZone: http://server1:8000/eureka/

7.建立 homepageCourse 实体表

package cn.chenforcode.homepage.entity;

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
import org.hibernate.annotations.UpdateTimestamp;
import org.springframework.data.annotation.CreatedDate;
import org.springframework.data.annotation.LastModifiedDate;
import org.springframework.data.jpa.domain.support.AuditingEntityListener;

import javax.persistence.*;
import java.util.Date;

/**
 * @author <a href="http://www.chenforcode.cn">PKUCoder</a>
 * @date 2019/11/11 4:12 下午
 * @description homepage_course表映射实体
 */
@Data
@NoArgsConstructor
@AllArgsConstructor
@Entity
@Table(name = "homepage_course")
@EntityListeners(AuditingEntityListener.class)
public class HomepageCourse {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "id", nullable = false)
    private Long id;

    //课程名称
    @Basic
    @Column(name = "course_name", nullable = false)
    private String courseName;

    //课程类型 0(免费课),1(实战课)
    @Basic
    @Column(name = "course_type", nullable = false)
    private Integer courseType;

    //课程图标
    @Basic
    @Column(name = "course_icon", nullable = false)
    private String courseIcon;

    //课程介绍
    @Basic
    @Column(name = "course_intro", nullable = false)
    private String courseIntro;

    //创建时间
    @Basic
    @Column(name = "create_time", nullable = false)
    @CreatedDate
    private Date CreateTime;

    //更新时间
    @Basic
    @Column(name = "update_time", nullable = false)
    @LastModifiedDate
    private Date updateTime;

    public HomepageCourse(String courseName, Integer courseType, String courseIcon, String courseIntro) {
        this.courseName = courseName;
        this.courseType = courseType;
        this.courseIcon = courseIcon;
        this.courseIntro = courseIntro;
    }

    /**
     * @Author <a href="http://www.chenforcode.cn">PKUCoder</a>
     * @Date 2019/11/11 4:27 下午
     * @Param []
     * @Return cn.chenforcode.homepage.entity.HomepageCourse
     * @Description 返回一个无效的course
     **/
    public static HomepageCourse invalid() {
        HomepageCourse invalid = new HomepageCourse("", 0, "", "");
        invalid.setId(-1L);
        return invalid;
    }
}

8.建立对应的仓库

package cn.chenforcode.homepage.repository;

import cn.chenforcode.homepage.entity.HomepageCourse;
import org.springframework.data.jpa.repository.JpaRepository;

public interface HomepageCourseRepository extends JpaRepository<HomepageCourse, Long> {
}