第一篇：如何拆分微服务

朱雀 2024-03-23 19:35 52阅读 0赞

## SpringCloud教学文章 ##

### 第一篇：如何拆分微服务 ###

简介：本文讲解如何如何利用SpringCloud进行微服务的拆分。

#### 样例结构 ####

![在这里插入图片描述][7da38070bdad49c2ace84cf2a6698044.png]  
cloud-demo：父工程，管理依赖

*  order-service：订单微服务，负责订单相关业务
 *  user-service：用户微服务，负责用户相关业务

要求：

*  订单微服务和用户微服务都必须有各自的数据库，相互独立
 *  订单服务和用户服务都对外暴露Restful的接口
 *  订单服务如果需要查询用户信息，只能调用用户服务的Restful接口，不能查询用户数据库

#### 数据库数据 ####

*  cloud-order.sql

-- ----------------------------
    -- Table structure for tb_order
    -- ----------------------------
    DROP TABLE IF EXISTS `tb_order`;
    CREATE TABLE `tb_order`  (
      `id` bigint(20) NOT NULL AUTO_INCREMENT COMMENT '订单id',
      `user_id` bigint(20) NOT NULL COMMENT '用户id',
      `name` varchar(100) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL COMMENT '商品名称',
      `price` bigint(20) NOT NULL COMMENT '商品价格',
      `num` int(10) NULL DEFAULT 0 COMMENT '商品数量',
      PRIMARY KEY (`id`) USING BTREE,
      UNIQUE INDEX `username`(`name`) USING BTREE
    ) ENGINE = InnoDB AUTO_INCREMENT = 109 CHARACTER SET = utf8 COLLATE = utf8_general_ci ROW_FORMAT = Compact;
    
    -- ----------------------------
    -- Records of tb_order
    -- ----------------------------
    INSERT INTO `tb_order` VALUES (101, 1, 'Apple 苹果 iPhone 12 ', 699900, 1);
    INSERT INTO `tb_order` VALUES (102, 2, '雅迪 yadea 新国标电动车', 209900, 1);
    INSERT INTO `tb_order` VALUES (103, 3, '骆驼（CAMEL）休闲运动鞋女', 43900, 1);
    INSERT INTO `tb_order` VALUES (104, 4, '小米10 双模5G 骁龙865', 359900, 1);
    INSERT INTO `tb_order` VALUES (105, 5, 'OPPO Reno3 Pro 双模5G 视频双防抖', 299900, 1);
    INSERT INTO `tb_order` VALUES (106, 6, '美的（Midea) 新能效 冷静星II ', 544900, 1);
    INSERT INTO `tb_order` VALUES (107, 2, '西昊/SIHOO 人体工学电脑椅子', 79900, 1);
    INSERT INTO `tb_order` VALUES (108, 3, '梵班（FAMDBANN）休闲男鞋', 31900, 1);

*  cloud-user.sql

-- ----------------------------
    -- Table structure for tb_user
    -- ----------------------------
    DROP TABLE IF EXISTS `tb_user`;
    CREATE TABLE `tb_user`  (
      `id` bigint(20) NOT NULL AUTO_INCREMENT,
      `username` varchar(100) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL COMMENT '收件人',
      `address` varchar(255) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL COMMENT '地址',
      PRIMARY KEY (`id`) USING BTREE,
      UNIQUE INDEX `username`(`username`) USING BTREE
    ) ENGINE = InnoDB AUTO_INCREMENT = 109 CHARACTER SET = utf8 COLLATE = utf8_general_ci ROW_FORMAT = Compact;
    
    -- ----------------------------
    -- Records of tb_user
    -- ----------------------------
    INSERT INTO `tb_user` VALUES (1, '柳岩', '湖南省衡阳市');
    INSERT INTO `tb_user` VALUES (2, '文二狗', '陕西省西安市');
    INSERT INTO `tb_user` VALUES (3, '华沉鱼', '湖北省十堰市');
    INSERT INTO `tb_user` VALUES (4, '张必沉', '天津市');
    INSERT INTO `tb_user` VALUES (5, '郑爽爽', '辽宁省沈阳市大东区');
    INSERT INTO `tb_user` VALUES (6, '范兵兵', '山东省青岛市');

![在这里插入图片描述][dd0babfcef864eaeac2f61a4ac6230b8.png]

#### 后端配置 ####

##### 项目结构 #####

![在这里插入图片描述][01d67e412e8d4048be3892b02ba3576b.png]

##### 父工程 #####

*  文件结构  
    ![在这里插入图片描述][3eae2fcb7e114effba845918363a61e1.png]
 *  pom.xml

这个父工程的pom.xml算是祖传的

<?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>cn.itcast.demo</groupId>
        <artifactId>cloud-demo</artifactId>
        <version>1.0</version>
        <modules>
            <module>user-service</module>
            <module>order-service</module>
        </modules>
    
        <packaging>pom</packaging>
    
        <parent>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-parent</artifactId>
            <version>2.3.9.RELEASE</version>
            <relativePath/>
        </parent>
    
        <properties>
            <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
            <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
            <java.version>1.8</java.version>
            <spring-cloud.version>Hoxton.SR10</spring-cloud.version>
            <mysql.version>5.1.47</mysql.version>
            <mybatis.version>2.1.1</mybatis.version>
        </properties>
    
        <dependencyManagement>
            <dependencies>
                
                <dependency>
                    <groupId>org.springframework.cloud</groupId>
                    <artifactId>spring-cloud-dependencies</artifactId>
                    <version>${spring-cloud.version}</version>
                    <type>pom</type>
                    <scope>import</scope>
                </dependency>
                
                <dependency>
                    <groupId>mysql</groupId>
                    <artifactId>mysql-connector-java</artifactId>
                    <version>${mysql.version}</version>
                </dependency>
                
                <dependency>
                    <groupId>org.mybatis.spring.boot</groupId>
                    <artifactId>mybatis-spring-boot-starter</artifactId>
                    <version>${mybatis.version}</version>
                </dependency>
            </dependencies>
        </dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.projectlombok</groupId>
                <artifactId>lombok</artifactId>
            </dependency>
        </dependencies>
    </project>

##### 子工程 #####

###### order-service ######

*  pom.xml  
    对于子工程要通过，`<parent>`来引入父工程的pom.xml

*  application.yml

server:
      port: 8080
    spring:
      datasource:
        url: jdbc:mysql://localhost:3306/cloud_order?useSSL=false
        username: root
        password: 123456
        driver-class-name: com.mysql.jdbc.Driver
    mybatis:
      type-aliases-package: cn.itcast.user.pojo
      configuration:
        map-underscore-to-camel-case: true
    logging:
      level:
        cn.itcast: debug
      pattern:
        dateformat: MM-dd HH:mm:ss:SSS

*  OrderApplication

@MapperScan("cn.itcast.order.mapper")
    @SpringBootApplication
    public class OrderApplication {
        
    
        public static void main(String[] args) {
        
            SpringApplication.run(OrderApplication.class, args);
        }
    
    }

*  OrderMapper

public interface OrderMapper {
        
    
        @Select("select * from tb_order where id = #{id}")
        Order findById(Long id);
    }

*  Order

@Data
    public class Order {
        
        private Long id;
        private Long price;
        private String name;
        private Integer num;
        private Long userId;
        private User user;
    }

*  User

@Data
    public class User {
        
        private Long id;
        private String username;
        private String address;
    }

*  OrderService

@Service
    public class OrderService {
        
    
        @Autowired
        private OrderMapper orderMapper;
    
        public Order queryOrderById(Long orderId) {
        
            // 1.查询订单
            Order order = orderMapper.findById(orderId);
            // 4.返回
            return order;
        }
    }

*  OrderController

@RestController
    @RequestMapping("order/")
    public class OrderController {
        
    
       @Autowired
       private OrderService orderService;
    
        @GetMapping("{orderId}")
        public Order queryOrderByUserId(@PathVariable("orderId") Long orderId) {
        
            // 根据id查询订单并返回
            return orderService.queryOrderById(orderId);
        }
    }

###### user-service ######

*  文件结构  
    ![在这里插入图片描述][ea3bb5bfa46d40f5925d7edb723f0ba7.png]
 *  pom.xml

*  application.yml

server:
      port: 8081
    spring:
      datasource:
        url: jdbc:mysql://localhost:3306/cloud_user?useSSL=false
        username: root
        password: 123456
        driver-class-name: com.mysql.jdbc.Driver
    mybatis:
      type-aliases-package: cn.itcast.user.pojo
      configuration:
        map-underscore-to-camel-case: true
    logging:
      level:
        cn.itcast: debug
      pattern:
        dateformat: MM-dd HH:mm:ss:SSS

*  UserApplication

@MapperScan("cn.itcast.user.mapper")
    @SpringBootApplication
    public class UserApplication {
        
        public static void main(String[] args) {
        
            SpringApplication.run(UserApplication.class, args);
        }
    }

*  UserMapper

public interface UserMapper {
        
        
        @Select("select * from tb_user where id = #{id}")
        User findById(@Param("id") Long id);
    }

*  User

@Data
    public class User {
        
        private Long id;
        private String username;
        private String address;
    }

*  UserService

@Service
    public class UserService {
        
    
        @Autowired
        private UserMapper userMapper;
    
        public User queryById(Long id) {
        
            return userMapper.findById(id);
        }
    }

*  UserController

@Slf4j
    @RestController
    @RequestMapping("/user")
    public class UserController {
        
    
        @Autowired
        private UserService userService;
    
        /**
         * 路径： /user/110
         *
         * @param id 用户id
         * @return 用户
         */
        @GetMapping("/{id}")
        public User queryById(@PathVariable("id") Long id) {
        
            return userService.queryById(id);
        }
    }

#### 项目运行演示 ####

![在这里插入图片描述][1c08662a484c46698a4b9f0c9dc759f7.png]

在order-service服务中，有一个根据id查询订单的接口：  
![在这里插入图片描述][034a7cf8e5564347992274a8304ecb22.png]

根据id查询订单，返回值是Order对象，如图：  
其中的user为null  
![在这里插入图片描述][5e0cb82f763b44ed99d7c5a791ae4812.png]

在user-service中有一个根据id查询用户的接口：  
![在这里插入图片描述][7ff3572b34494c83b2bac9f62e97514a.png]

查询的结果如图：  
![在这里插入图片描述][58173c1969494cf5b244ed3a16c039e6.png]

#### 案例需求 ####

##### 简介 #####

修改order-service中的根据id查询订单业务，要求在查询订单的同时，根据订单中包含的userId查询出用户信息，一起返回。

![在这里插入图片描述][2602b47d3bc0445e9bcca6c91b984846.png]  
因此，我们需要在order-service中 向user-service发起一个http的请求，调用http://localhost:8081/user/\{userId\}这个接口。

大概的步骤是这样的：

*  注册一个RestTemplate的实例到Spring容器
 *  修改order-service服务中的OrderService类中的queryOrderById方法，根据Order对象中的userId查询User
 *  将查询的User填充到Order对象，一起返回

##### 注册RestTemplate #####

首先，我们在order-service服务中的OrderApplication启动类中，注册RestTemplate实例：  
![在这里插入图片描述][d30be770917941e19706ba5233ec6cdf.png]

import org.mybatis.spring.annotation.MapperScan;
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    import org.springframework.context.annotation.Bean;
    import org.springframework.web.client.RestTemplate;
    
    @MapperScan("cn.itcast.order.mapper")
    @SpringBootApplication
    public class OrderApplication {
        
    
        public static void main(String[] args) {
        
            SpringApplication.run(OrderApplication.class, args);
        }
    
        @Bean
        public RestTemplate restTemplate() {
        
            return new RestTemplate();
        }
    }

##### 实现远程调用 #####

修改order-service服务中的cn.itcast.order.service包下的OrderService类中的queryOrderById方法：  
![在这里插入图片描述][1c9f8904516b4dbb84582d3538d2defb.png]

@Service
    public class OrderService {
        
    
        @Autowired
        private OrderMapper orderMapper;
    
        @Autowired
        private RestTemplate restTemplate;
    
        public Order queryOrderById(Long orderId) {
        
            // 1.查询订单
            Order order = orderMapper.findById(orderId);
            // 2.远程查询user
            // 2.1 url地址
            String url = "http://localhost:8081/user/" + order.getUserId();
            // 2.2发起调用
            User user = restTemplate.getForObject(url, User.class);
            // 3. 存入order
            order.setUser(user);
            // 4.返回
            return order;
        }
    }

##### 运行效果 #####

![在这里插入图片描述][77ceabe7223b4fc7901930d13a170839.png]

[7da38070bdad49c2ace84cf2a6698044.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/14/f92ca8569fe643d192f4fb9770f7ccf7.png
[dd0babfcef864eaeac2f61a4ac6230b8.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/14/e8d791ce41314a739afd2089f485c93d.png
[01d67e412e8d4048be3892b02ba3576b.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/14/827aefba1fd24633938d38f2c7b06299.png
[3eae2fcb7e114effba845918363a61e1.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/14/62bf8623338048779155cb5c8f767463.png
[ea3bb5bfa46d40f5925d7edb723f0ba7.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/14/a3f234cfca504b17a5cd26725743451d.png
[1c08662a484c46698a4b9f0c9dc759f7.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/14/ada1fd4596694612985189a2931458e1.png
[034a7cf8e5564347992274a8304ecb22.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/14/d82b3145e3c648e6a7031327fa28dfb7.png
[5e0cb82f763b44ed99d7c5a791ae4812.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/14/dd6015d52bfd468aad019a70a28d06a6.png
[7ff3572b34494c83b2bac9f62e97514a.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/14/8e1b6d622f0b49e28ab4f3469b6e6ad5.png
[58173c1969494cf5b244ed3a16c039e6.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/14/a51696161a6f4a7f8ac8d35be11c8632.png
[2602b47d3bc0445e9bcca6c91b984846.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/14/db25d8f3cee944d3926467aeed677ccd.png
[d30be770917941e19706ba5233ec6cdf.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/14/a6787e94499a41e3a471703cb3617ed9.png
[1c9f8904516b4dbb84582d3538d2defb.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/14/0eb4e79c2e0e421d8c84e6338ff57990.png
[77ceabe7223b4fc7901930d13a170839.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/14/fbf97c1e6ec24ceeb691221fa2f5da28.png