SpringCloud系列（14）--Eureka服务发现(Discovery)

news2024/11/18 3:40:39

前言：在上一章节中我们说明了一些关于服务信息的配置，在本章节则介绍一些关于Discovery的知识点及其使用

1、Discovery是什么，有什么用

Discovery（服务发现）是eureka的功能和特性，有时候微服务可能需要对外提供一种功能，这个功能可以对外提供服务IP、服务名称、端口号等服务信息，而这时候Discovery就能实现这个功能，Discovery能对外暴露注册进Eureka里的服务信息

2、启用服务发现

在provider-payment8001模块的启动类里加上@EnableDiscoveryClinet这一注解来启用服务发现

package com.ken.springcloud;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;

@SpringBootApplication
//标注为Eureka Client（服务注册中心）
@EnableEurekaClient
@EnableDiscoveryClient
public class PaymentMain {
    public static void main(String[] args) {
        SpringApplication.run(PaymentMain.class, args);
    }
}

效果图：

3、实现服务发现接口

在provider-payment8001模块的PaymentController类里注入DiscoveryClient接口，然后利用DiscoveryClient接口的方法在PaymentController类里实现服务发现接口

package com.ken.springcloud.controller;

import com.ken.springcloud.entities.CommonResult;
import com.ken.springcloud.entities.Payment;
import com.ken.springcloud.service.PaymentService;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.cloud.client.ServiceInstance;
import org.springframework.cloud.client.discovery.DiscoveryClient;
import org.springframework.web.bind.annotation.*;

import javax.annotation.Resource;
import java.util.List;

@RestController
@Slf4j
public class PaymentController {

    @Resource
    private PaymentService paymentService;

    @Value("${server.port}")
    private String serverPort;

    @Resource
    private DiscoveryClient discoveryClient;

    @PostMapping("/payment/insert")
    public CommonResult insert(@RequestBody Payment payment) {
        int result = paymentService.insert(payment);
        log.info("插入结果{}",result);
        if(result > 0) {
            return new CommonResult(200,"插入数据库成功，提供服务的端口号为" + serverPort,result);
        }else {
            return new CommonResult(500,"插入数据库失败",result);
        }
    }

    @GetMapping("/payment/get/{id}")
    public CommonResult insert(@PathVariable("id") Long id) {
        Payment payment = paymentService.getPaymentById(id);
        log.info("查询结果{}",payment);
        if(payment != null) {
            return new CommonResult(200,"查询成功，提供服务的端口号为" + serverPort,payment);
        }else {
            return new CommonResult(500,"没有对应的数据，查询失败，查询id" + id,payment);
        }
    }

    @GetMapping("/payment/discovery")
    public Object discovery() {
        //获取eureka内的服务
        List<String> services = discoveryClient.getServices();
        for (String service : services) {
            log.info("***service:" + service);
        }
        //获取服务名为CLOUD-PAYMENT-SERVICE下的实例
        List<ServiceInstance> instances = discoveryClient.getInstances("CLOUD-PAYMENT-SERVICE");
        for (ServiceInstance instance : instances) {
            log.info(instance.getServiceId()+"\t"+instance.getHost()+"\t"+instance.getPort()+"\t"+instance.getUri());
        }
        return this.discoveryClient;
    }

}

效果图：