SpringCloud学习一(微服务远程调用案例:入门)
前提:准备两个数据库,并创建数据库表
项目代码路径:ZhongChunle/cloud-demo: 微服务远程调用接口案例 (github.com)
cloud_order
数据量下创建订单数据库表
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;
cloud_user
数据库下创建用户表
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;
2、创建项目
springboot项目的创建就一一步一步来了,直接看控制器和启动类
远程调用服务需要使用到spring提供的RestTemplate
,并注入给spring容器,在启动类中设置
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);
}
/**
* 创建RestTemplate并注入spring容器
* @return
*/
@Bean
public RestTemplate restTemplate() {
return new RestTemplate();
}
}
在业务逻辑层中注入RestTemplate
进行请求调用
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;
/**
* 注入发起请求
*/
@Autowired
private RestTemplate restTemplate;
public Order queryOrderById(Long orderId) {
// 1.查询订单
Order order = orderMapper.findById(orderId);
// 2、利用RestTemplate发起http请求,查询用户
String url = "http://localhost:8081/user/"+order.getUserId();
// 3、发送请求
User user = restTemplate.getForObject(url, User.class);
order.setUser(user);
// 4.返回
return order;
}
}
想要什么类型的请求都可以设定
查询结果
{
"id": 102,
"price": 209900,
"name": "雅迪 yadea 新国标电动车",
"num": 1,
"userId": 2,
"user": {
"id": 2,
"username": "文二狗",
"address": "陕西省西安市"
}
}
服务调用关系
- 服务提供者:暴露接口给其他微服务调用
- 服务消费者:调用其他微服务提供接口
- 提供者与消费者角色是相对的
一个服务可以同时是服务提供者和服务消费者