向註冊中心註冊數據微服務

本博客參考http://how2j.cn/k/springcloud/springcloud-eureka-client/2039.html#nowhere後編寫

如果不知道怎麼創建註冊中心請移步   springCloud在父子項目基礎上創建服務註冊中心

1.創建子項目product-data-service

2.pom.xml內容如下

spring-cloud-starter-netflix-eureka-client 表示這是個 eureka 客戶端。
spring-boot-starter-web: 表示這是個web服務，會提供控制層

<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>
  <parent>
    <groupId>cn.how2j.springcloud</groupId>
    <artifactId>springcloud</artifactId>
    <version>0.0.1-SNAPSHOT</version>
  </parent>
  <artifactId>productDataservice</artifactId>
   
    <dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>     
    </dependencies>
       
</project>

3.創建ProductController.java代碼如下

package cn.how2j.springcloud.controller;
 
import java.util.List;
 
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
 
import cn.how2j.springcloud.pojo.Product;
import cn.how2j.springcloud.service.ProductService;
  
@RestController
public class ProductController {
  
    @Autowired ProductService productService;
     
    @RequestMapping("/products")
    public Object products() {
        List<Product> ps = productService.listProducts();
        return ps;
    }
}

4.創建Product.java代碼如下

package cn.how2j.springcloud.pojo;
 
public class Product {
 
    private int id;
    private String name;
    private int price;
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public int getPrice() {
        return price;
    }
    public void setPrice(int price) {
        this.price = price;
    }
 
    public Product() {
         
    }
    public Product(int id, String name, int price) {
        super();
        this.id = id;
        this.name = name;
        this.price = price;
    }
 
}

5.創建ProductService.java代碼如下

package cn.how2j.springcloud.service;
 
import java.util.ArrayList;
import java.util.List;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Service;
 
import cn.how2j.springcloud.pojo.Product;
 
@Service
public class ProductService {
    @Value("${server.port}")
    String port;
     
    public List<Product> listProducts(){
        List<Product> ps = new ArrayList<>();
        ps.add(new Product(1,"product a from port:"+port, 50));
        ps.add(new Product(2,"product b from port:"+port, 150));
        ps.add(new Product(3,"product c from port:"+port, 250));
        return ps;
    }
}

6.創建ProductDataServiceApplication.java代碼如下

啓動第二個項目的時候別忘了修改端口號

package cn.how2j.springcloud;
 
import java.util.Scanner;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Future;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.builder.SpringApplicationBuilder;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
import cn.hutool.core.convert.Convert;
import cn.hutool.core.thread.ThreadUtil;
import cn.hutool.core.util.NetUtil;
import cn.hutool.core.util.NumberUtil;
 
/**向註冊中心中註冊
 * @author xiaojian
 *
 */
@SpringBootApplication
@EnableEurekaClient
public class ProductDataServiceApplication {
    public static void main(String[] args) {
        int port = 0;
        int defaultPort = 8002;
        Future<Integer> future = ThreadUtil.execAsync(() ->{
                int p = 0;
                System.out.println("請於5秒鐘內輸入端口號, 推薦  8001 、 8002  或者  8003，超過5秒將默認使用 " + defaultPort);
                Scanner scanner = new Scanner(System.in);
                while(true) {
                    String strPort = scanner.nextLine();
                    if(!NumberUtil.isInteger(strPort)) {
                        System.err.println("只能是數字");
                        continue;
                    }
                    else {
                        p = Convert.toInt(strPort);
                        scanner.close();
                        break;
                    }
                }
                return p;
        });
        try{
            port=future.get(5,TimeUnit.SECONDS);
        }
        catch (InterruptedException | ExecutionException | TimeoutException e){
            port = defaultPort;
        }
         
        if(!NetUtil.isUsableLocalPort(port)) {
            System.err.printf("端口%d被佔用了，無法啓動%n", port );
            System.exit(1);
        }
         
        new SpringApplicationBuilder(ProductDataServiceApplication.class).properties("server.port=" + port).run(args);
    }
}

7.創建application.yml代碼如下

http://localhost:8761/eureka/ 和註冊中心對應

#   server:
#   port: 因爲會啓動多個 product-data-service, 所以端口號由用戶自動設置，推薦 8001,8002,8003
 
spring:
  application:
    name: product-data-service
eureka:
  client:
    serviceUrl:
      defaultZone: http://localhost:8761/eureka/

8.操作步驟：先啓動註冊中心，然後啓動product-data-service項目（端口號爲8001），修改product-data-service端口號（端口號爲8002）後再啓動一次，這是訪問http://127.0.0.1:8761/會發現有端口號爲8001和8002的兩個服務

可以如此訪問： http://127.0.0.1:8001/products ，http://127.0.0.1:8002/products，並看到如圖所示的數據。
但是這種方式是通過 http 協議 訪問微服務本身，和註冊中心沒有關係，也觀察不到集羣的效果，接下來我們就會講如何用微服務，訪問另一個微服務。