- 1、服务拆分 - 案例Demo
- 不说那么多，直接上代码
- 2、微服务远程调用
服务拆分注意事项
- 不同微服务，不要重复开发相同业务
- 微服务数据独立，不要访问其他微服务数据库
- 微服务可以将自己的业务暴露为接口，共其它微服务调用
-
项目结构
-
数据库
-
数据库-order
SET NAMES utf8mb4; SET FOREIGN_KEY_CHECKS = 0; -- ---------------------------- -- 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); SET FOREIGN_KEY_CHECKS = 1;
- 数据库-user
SET NAMES utf8mb4; SET FOREIGN_KEY_CHECKS = 0; -- ---------------------------- -- 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'); SET FOREIGN_KEY_CHECKS = 1;
- 父工程pom.xml
4.0.0 cn.itcast.demo cloud-demo 1.0 user-service order-service pom org.springframework.boot spring-boot-starter-parent 2.3.9.RELEASE UTF-8 UTF-8 1.8 Hoxton.SR10 5.1.47 2.1.1 org.springframework.cloud spring-cloud-dependencies ${spring-cloud.version} pom import mysql mysql-connector-java ${mysql.version} org.mybatis.spring.boot mybatis-spring-boot-starter ${mybatis.version} org.projectlombok lombok
- order-service 订单服务
pom.xml
cloud-demo cn.itcast.demo 1.0 4.0.0 order-service org.springframework.boot spring-boot-starter-web mysql mysql-connector-java org.mybatis.spring.boot mybatis-spring-boot-starter org.springframework.boot spring-boot-maven-plugin
yml
server:
port: 8080
spring:
datasource:
url: jdbc:mysql://localhost:3306/cloud_order?useSSL=false
username: root
password: xxx
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
pojo
package cn.itcast.order.pojo;
import lombok.Data;
@Data
public class User {
private Long id;
private String username;
private String address;
}
package cn.itcast.order.pojo;
import lombok.Data;
@Data
public class Order {
private Long id;
private Long price;
private String name;
private Integer num;
private Long userId;
private User user;
}
controller
package cn.itcast.order.web;
import cn.itcast.order.pojo.Order;
import cn.itcast.order.service.OrderService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
@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);
}
}
service
package cn.itcast.order.service;
import cn.itcast.order.mapper.OrderMapper;
import cn.itcast.order.pojo.Order;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
@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;
}
}
mapper
package cn.itcast.order.mapper;
import cn.itcast.order.pojo.Order;
import org.apache.ibatis.annotations.Select;
public interface OrderMapper {
@Select("select * from tb_order where id = #{id}")
Order findById(Long id);
}
application
package cn.itcast.order;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;
@MapperScan("cn.itcast.order.mapper")
@SpringBootApplication
public class OrderApplication {
public static void main(String[] args) {
SpringApplication.run(OrderApplication.class, args);
}
}
- user-service 用户服务
pom.xml
cloud-demo cn.itcast.demo 1.0 4.0.0 user-service org.springframework.boot spring-boot-starter-web mysql mysql-connector-java org.mybatis.spring.boot mybatis-spring-boot-starter app org.springframework.boot spring-boot-maven-plugin
yml
server:
port: 8081
spring:
datasource:
url: jdbc:mysql://localhost:3306/cloud_user?useSSL=false
username: root
password: xxx
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
pojo
package cn.itcast.order.pojo;
import lombok.Data;
@Data
public class User {
private Long id;
private String username;
private String address;
}
controller
package cn.itcast.user.web;
import cn.itcast.user.pojo.User;
import cn.itcast.user.service.UserService;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;
@Slf4j
@RestController
@RequestMapping("/user")
public class UserController {
@Autowired
private UserService userService;
@GetMapping("/{id}")
public User queryById(@PathVariable("id") Long id) {
return userService.queryById(id);
}
}
service
package cn.itcast.user.service;
import cn.itcast.user.mapper.UserMapper;
import cn.itcast.user.pojo.User;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
@Service
public class UserService {
@Autowired
private UserMapper userMapper;
public User queryById(Long id) {
return userMapper.findById(id);
}
}
mapper
package cn.itcast.user.mapper;
import cn.itcast.user.pojo.User;
import org.apache.ibatis.annotations.Param;
import org.apache.ibatis.annotations.Select;
public interface UserMapper {
@Select("select * from tb_user where id = #{id}")
User findById(@Param("id") Long id);
}
application
package cn.itcast.user;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.mybatis.spring.annotation.MapperScan;
@MapperScan("cn.itcast.user.mapper")
@SpringBootApplication
public class UserApplication {
public static void main(String[] args) {
SpringApplication.run(UserApplication.class, args);
}
}
- 运行结果
用户服务运行结果
订单服务运行结果
需求：根据订单id查询订单的同时，把订单所属的用户信息一起返回 根据上面的运行写结果来看，根据订单id查询订单时只查到了订单信息，用户信息为null,不满组需求
- 远程调用方式分析
这里就可以用到Spring 提供的 RestTemple 用于发送 http 请求
修改OrderApplication.java 代码
package cn.itcast.order;
import com.netflix.loadbalancer.IRule;
import com.netflix.loadbalancer.RandomRule;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.loadbalancer.LoadBalanced;
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);
}
// Spring 提供 RestTemple 用于发送 http 请求
@Bean
@LoadBalanced
public RestTemplate restTemplate(){
return new RestTemplate();
}
}
修改OrderService.java 代码，RestTemplate中的getForObject方法发送 http 请求，实现远程调用
package cn.itcast.order.service;
import cn.itcast.order.mapper.OrderMapper;
import cn.itcast.order.pojo.Order;
import cn.itcast.order.pojo.User;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.web.client.RestTemplate;
@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.利用 restTemplate 访问 http 请求
// 2.1请求 url
String url = "http://userserver/user/" + order.getUserId();
// 2.2发送 http 请求，实现远程调用
User user = restTemplate.getForObject(url, User.class);
// 3.封装 user 到 Order
order.setUser(user);
// 4.返回
return order;
}
}
这样在代码中写死请求url的方式在实际应用中并不可取，
因为会遇到各种各样的问题如下：
- 如果服务地址发生改变，服务消费者如何获取服务提供者的地址信息？
- 如果有多个服务提供者，消费者该如何选择？
- 消费者如何得知服务提供者的健康状态？
