【SpringCloud 2021.0.0】2、服务提供者 REST (spring-boot 2.6.3)

1、创建父工程

1）创建普通Meven工程

创建普通Meven工程，删除 src 目录，保留 pom.xml

2）pom.xml

<?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">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.tuwer</groupId>
    <artifactId>springcloud</artifactId>
    <version>1.0-SNAPSHOT</version>
    <modules>
        <module>xxx</module>
        <module>xxx</module>
        <module>xxx</module>
    </modules>
    <!--打包方式：pom 表示是父类工程-->
    <packaging>pom</packaging>

    <properties>
        <maven.compiler.source>8</maven.compiler.source>
        <maven.compiler.target>8</maven.compiler.target>

        <mysql.version>8.0.28</mysql.version>
        <druid.version>1.2.8</druid.version>
        <lombok.version>1.18.22</lombok.version>
        <log4j.version>1.2.17</log4j.version>
    </properties>

    <!--管理jar包的版本，让子项目中引用一个依赖而不用显式的列出版本号-->
    <dependencyManagement>
        <dependencies>
            <!--spring-cloud-dependencies-->
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>2021.0.0</version>
                <!--
                解决Maven项目单继承问题:
                Maven的继承和Java的继承一样，只能单继承，无法实现多继承
                pom 说明导入的是一个父模块，
                后面的scope标签中的值 import 代表把父模块中的jar包导入进来
                <type>pom</type><scope>import</scope>,
                只能用在<dependencyManagement></dependencyManagement>中
                -->
                <type>pom</type>
                <scope>import</scope>
            </dependency>
            <!-- spring-boot-dependencies -->
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-dependencies</artifactId>
                <version>2.6.3</version>
                <type>pom</type>
                <!--<scope>provided</scope>-->
                <scope>import</scope>
            </dependency>
            <!--数据库-->
            <dependency>
                <groupId>mysql</groupId>
                <artifactId>mysql-connector-java</artifactId>
                <version>${mysql.version}</version>
            </dependency>
            <dependency>
                <groupId>com.alibaba</groupId>
                <artifactId>druid</artifactId>
                <version>${druid.version}</version>
            </dependency>
            <!--SpringBoot mybatis启动器-->
            <dependency>
                <groupId>org.mybatis.spring.boot</groupId>
                <artifactId>mybatis-spring-boot-starter</artifactId>
                <version>2.2.2</version>
            </dependency>
            <!--lombok-->
            <dependency>
                <groupId>org.projectlombok</groupId>
                <artifactId>lombok</artifactId>
                <version>${lombok.version}</version>
            </dependency>
            <!--日志-->
            <dependency>
                <groupId>log4j</groupId>
                <artifactId>log4j</artifactId>
                <version>${log4j.version}</version>
            </dependency>
        </dependencies>
    </dependencyManagement>
    <build>
        <resources>
            <resource>
                <directory>src/main/resources</directory>
                <filtering>true</filtering>
            </resource>
        </resources>
        <plugins>
            <plugin>
                <!-- 打包插件 -->
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>
</project>

• <packaging>pom</packaging>

  打包方式：pom 表示是父类工程

• dependencyManagement

  统一管理jar包的版本，让子项目中引用一个依赖而不用显式的列出版本号

• <type>pom</type> <scope>import</scope>

  解决Maven项目单继承问题:

  • Maven的继承和Java的继承一样，只能单继承，无法实现多继承
  • pom 说明导入的是一个父模块
  • 后面的scope标签中的值 import 代表把父模块中的jar包导入进来
  • <type>pom</type><scope>import</scope>，只能用在 <dependencyManagement> 中

• <properties>

  可以把相关依赖的版本信息提取出来，放在 <properties> 中

2、创建 API 实体类子模块

只存放 pojo 层

1）创建普通Meven工程

在父工程下创建；创建后父工程pom.xml中会增加 modules 模块

<modules>
    <module>springcloud-api</module>
</modules>

• pom.xml

  导入 lombak

  因为父工程中有了 dependencyManagement 管理依赖，子工程中不需要写版本号

<?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>springcloud</artifactId>
        <groupId>com.tuwer</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>springcloud-api</artifactId>

    <properties>
        <maven.compiler.source>8</maven.compiler.source>
        <maven.compiler.target>8</maven.compiler.target>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
        </dependency>
    </dependencies>

</project>

2）建立数据库

• 数据库：springcloud_db01
• 数据表：department

• 插入数据

# 先使用数据库，再用 DATABASE() 可得到当前数据库名
use springcloud_db01;
insert into department(dept_name, db_source) VALUES ('开发部',DATABASE());
insert into department(dept_name, db_source) VALUES ('人事部',DATABASE());
insert into department(dept_name, db_source) VALUES ('市场部',DATABASE());
insert into department(dept_name, db_source) VALUES ('运维部',DATABASE());
insert into department(dept_name, db_source) VALUES ('财务部',DATABASE());
insert into department(dept_name, db_source) VALUES ('策划部',DATABASE());

3）创建实体类

• Department.java

package com.tuwer.springcloud.pojo;

import lombok.Data;
import lombok.NoArgsConstructor;
import lombok.experimental.Accessors;

import java.io.Serializable;

/**
 * @author 土味儿
 * Date 2022/2/9
 * @version 1.0
 */
@Data
@NoArgsConstructor
// 支持链式写法；默认为false
@Accessors(chain = true)
public class Department implements Serializable {
    private Long deptId;
    private String deptName;
    /**
     * 在微服务中，同一信息可以存在于不同的数据库中
     */
    private String dbSource;

    public Department(String deptName) {
        this.deptName = deptName;
    }
}

3、创建服务提供者模块

springcloud-provider-dept-8001

1）创建普通Meven工程

其实是一个SpringBoot工程

在Spring基础上，添加 application.yml 和主启动类，以及相关的jar包，就变成了SpringBoot工程

2）导jar包

<?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>springcloud</artifactId>
        <groupId>com.tuwer</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>springcloud-provider-dept-8001</artifactId>

    <properties>
        <maven.compiler.source>8</maven.compiler.source>
        <maven.compiler.target>8</maven.compiler.target>
    </properties>

    <dependencies>
        <!--自定义API依赖-->
        <dependency>
            <groupId>com.tuwer</groupId>
            <artifactId>springcloud-api</artifactId>
            <version>1.0-SNAPSHOT</version>
        </dependency>
        <!--数据库-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
        </dependency>
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
        </dependency>
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
        </dependency>
        <!--日志-->
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
        </dependency>
        <!--spring-boot-starter-web-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <!-- spring-boot-starter-jetty：类似tomcat的容器 -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-jetty</artifactId>
        </dependency>
        <!-- 热部署 -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
        </dependency>
    </dependencies>

</project>

• spring-boot-starter-web
• spring-boot-starter-jetty
• spring-boot-devtools

以上三个jar包都在 spring-boot-dependencies 中，已经在父工程中管理，可以省略版本号，直接导入

3）配置 application.yml

# 端口
server:
  port: 8001

# mybatis
mybatis:
  # 别名
  type-aliases-package: com.tuwer.springcloud.pojo
  # 配置文件
  #config-location: classpath:/mybatis/mybatis-config.xml
  # mapper.xml
  mapper-locations: classpath:/mybatis/mapper/*.xml
  configuration:
    # 驼峰命名
    map-underscore-to-camel-case: true
    # 显式的开启全局缓存
    cache-enabled: true

# spring
spring:
  application:
    # 服务名称
    name: springcloud-provider-dept
  # 数据源
  datasource:
    # 德鲁伊
    type: com.alibaba.druid.pool.DruidDataSource
    # 驱动
    driver-class-name: com.mysql.cj.jdbc.Driver
    username: root
    password: 123456
    url: jdbc:mysql://localhost:3306/springcloud_db01?useUnicode=true&characterEncoding=utf8&useSSL=true&serverTimezone=GMT%2B8

注意：

不要单独配置 mybatis-config.xml；mybatis的配置都放在 application.yml 中；否则容易出现冲突

4）Mapper接口

• DepartmentMapper.java

  @Mapper 、@Repository

package com.tuwer.springcloud.mapper;

import com.tuwer.springcloud.pojo.Department;
import org.apache.ibatis.annotations.Mapper;
import org.springframework.stereotype.Repository;

import java.util.List;

/**
 * @author 土味儿
 * Date 2022/2/9
 * @version 1.0
 */
@Mapper
@Repository
public interface DepartmentMapper {
    /**
     * 添加部门
     * @param department
     * @return
     */
    boolean addDepartment(Department department);

    /**
     * 根据Id查询部门
     * @param id
     * @return
     */
    Department queryById(Long id);

    /**
     * 查询全部部门
     * @return
     */
    List<Department> queryAll();
}

5）Mapper配置

位于 resources/mybatis/mapper 下面

• DepartmentMapper.xml

  命名空间 namespace 指向接口类

<?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.tuwer.springcloud.mapper.DepartmentMapper">

    <insert id="addDepartment" parameterType="department">
        insert into springcloud_db01.department(dept_name, db_source)
        VALUES (#{deptName},DATABASE())
    </insert>

    <select id="queryById" parameterType="long" resultType="department">
        select * from springcloud_db01.department
        where dept_id = #{deptId}
    </select>
    
    <select id="queryAll" resultType="department">
        select * from springcloud_db01.department
    </select>
</mapper>

6）Service层

（1）Service接口

• DepartmentService.java

public interface DepartmentService {
    /**
     * 添加部门
     * @param department
     * @return
     */
    boolean addDepartment(Department department);

    /**
     * 根据Id查询部门
     * @param id
     * @return
     */
    Department queryById(Long id);

    /**
     * 查询全部部门
     * @return
     */
    List<Department> queryAll();
}

（2）Service实现类

• DepartmentServiceImpl.java

  @Service

@Service
public class DepartmentServiceImpl implements DepartmentService {
    @Autowired
    DepartmentMapper departmentMapper;

    @Override
    public boolean addDepartment(Department department) {
        return departmentMapper.addDepartment(department);
    }

    @Override
    public Department queryById(Long id) {
        return departmentMapper.queryById(id);
    }

    @Override
    public List<Department> queryAll() {
        return departmentMapper.queryAll();
    }
}

7）Controller层

Controller 是对外提供服务的接口；用注解 @RestController

@RestController
public class DepartmentController {
    @Autowired
    DepartmentService departmentService;

    @PostMapping("/department/add")
    public boolean addDepartment(@RequestBody Department department){
        return departmentService.addDepartment(department);
    }

    @GetMapping("/department/get/{id}")
    public Department getDepartment(@PathVariable("id") Long id){
        return departmentService.queryById(id);
    }

    @GetMapping("/department/getAll")
    public List<Department> getAllDepartment(){
        return departmentService.queryAll();
    }
}

• @PostMapping 的添加方法中，在参数前面需要加上 @RequestBody，否则接收不到消费端传递的数据
• @RequestBody 接收的是json字符串，代表postForObject发送过来的对象其实是一个被格式化成json字符串的对象

8）添加主动启类

• DepartmentProvider_8001.java

@SpringBootApplication
public class DepartmentProvider_8001 {
    public static void main(String[] args) {
        SpringApplication.run(DepartmentProvider_8001.class,args);
    }
}

9）项目结构

10）测试