SpringCloud零基礎上手(四)——服務發現以及Feign(宣告式RESTful服務呼叫)
接著上篇的內容,我們再建立一個專案充當服務消費者,命名為pf-font,如果pf-login視為後端,那麼pf-font 就是前端,達到前後端分離的目的。
一、pf-front目錄結構
pf-front同樣是一個多模組專案,儘管它目前只有一個模組——pf-web,方便後面擴充套件其他模組。
二、結構組成
1、pf-font的pom.xml
<?xml version="1.0" encoding="UTF-8"?>
<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>
<groupId>cn.pw</groupId>
<artifactId>pf-front</artifactId>
<version>1.0-SNAPSHOT</version>
<packaging>pom</packaging >
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<java.version>1.8</java.version>
<spring-cloud.version>Dalston.SR4</spring-cloud.version >
<fastjson-version>1.2.15</fastjson-version>
</properties>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.5.8.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-eureka</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-feign</artifactId>
</dependency>
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>fastjson</artifactId>
<version>${fastjson-version}</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-thymeleaf</artifactId>
</dependency>
</dependencies>
<dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-dependencies</artifactId>
<version>${spring-cloud.version}</version>
<type>pom</type>
<scope>import</scope>
</dependency>
</dependencies>
</dependencyManagement>
<modules>
<module>pf-web</module>
</modules>
</project>
2、pf-web的pom.xml
<?xml version="1.0" encoding="UTF-8"?>
<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.pw</groupId>
<artifactId>pf-front</artifactId>
<version>1.0-SNAPSHOT</version>
</parent>
<artifactId>pf-web</artifactId>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
三、pf-web
1、啟動類
package cn.pw.platform.web;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
import org.springframework.cloud.netflix.feign.EnableFeignClients;
@SpringBootApplication
@EnableFeignClients
@EnableDiscoveryClient
public class WebApplication {
public static void main(String[] args) {
SpringApplication.run(WebApplication.class, args);
}
}
這裡我使用@EnableDiscoveryClient
而沒有使用@EnableEurekaClient
,因為後者只能為Eureka作用,而前者則依賴於classpath中的實現,也就是說@EnableDiscoveryClient
有多種實現,如eureka, consul, zookeeper,我們需要在application.yml中指定具體的實現。
@EnableFeignClients開啟了對Feign的支援 。
當我們在classpath中配置了eureka,
@EnableDiscoveryClient
和@EnableEurekaClient
作用是一樣的。
2、配置檔案application.yml
server:
port: 8680
spring:
thymeleaf:
mode: HTML5
encoding: utf-8
content-type: text/html
cache: false
application:
name: pf-web
eureka:
client:
service-url:
default-zone: http://127.0.0.1:8761/eureka/
instance:
instance-id: ${spring.cloud.client.ipAddress}:{server.port}
prefer-ip-address: true
這個配置不難看懂,Eureka的配置項中,我們將pf-web自身也註冊到了註冊中心。
現在啟動Eureka Server 和 pf-web ,我們在註冊中心的頁面可以得到驗證 。
四、使用Feign 呼叫 pf-login 的介面
1、在pf-web中定義Feign的呼叫介面
package cn.pw.platform.web.feign;
import cn.pw.platform.web.vo.UserVo;
import org.springframework.cloud.netflix.feign.FeignClient;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;
@FeignClient(name="pf-login-server")
public interface LoginClient {
@GetMapping("/selectUserByName/{userName}")
UserVo selectUserByName(@PathVariable("userName") String userName);
@PostMapping("/user/add")
UserVo addUser(@RequestBody UserVo userVo);
}
@FeignClient(name="pf-login-server")
指明瞭要呼叫的服務名,介面中定義的方法要符合被調服務的介面要求。
2、寫一個測試類Controller
package cn.pw.platform.web.controller;
import cn.pw.platform.web.feign.LoginClient;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.validation.BindingResult;
import org.springframework.web.bind.annotation.*;
@Controller
public class LoginController {
@Autowired
private LoginClient loginClient;
@GetMapping("/searchByName/{name}")
@ResponseBody
public UserVo searchByName(@PathVariable("name") String name){
return loginClient.selectUserByName(name);
}
}
3、補充 一個引數對映類UserVo用於封裝從服務端請求來的引數。
public class UserVo {
private Long id;
private String name;
private String nickName;
private String password;
private Integer age;
private Integer sex;
//...省略getter setter方法
}
4、測試
逐個啟動所需專案,Eureka Server、pf-login、pf-web。
結果:
{
“id”: 10,
“name”: “libin”,
“nickName”: null,
“password”: “123456”,
“age”: 18,
“sex”: null
}
和上一篇我們直接呼叫server,所獲取的結果完全一致。