1. 服务拆分

1.1 服务拆分的注意事项

1.2 服务拆分具体案例

1.2.1 数据库

首先新建2个数据库

CREATE DATABASE cloud_user;
CREATE DATABASE cloud_order;

然后执行下面的sql语句往里面插入数据

USE cloud_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;


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);

USE cloud_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;


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');

执行结果

1.2.2 代码

百度网盘分享

链接：https://pan.baidu.com/s/1pkQdUEaSLBR_kGfYCOfwkQ 
提取码：3210

could-demo项目里面有2个模块

接下来启动这2个模块，然后去游览器访问接口

我们可以发现，该项目完全遵循了单一职责的原则，每个项目都只做自己相关业务的事情。数据库也做了分离。

1.2.3 小结

2. 远程调用

2.1 需求

2.2 现状

2.3 解决办法

2.4 具体实现

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;
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();
    }
}

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. 查询用户
        // 2.1 url路径
        String url = "http://localhost:8081/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信息
        order.setUser(user);
        // 4.返回
        return order;
    }
}

2.5 小结