Spring Cloud 项目入门

旧城等待， 2021-11-29 08:16 302阅读 0赞

# Spring Cloud 项目关键点 #

### 文章目录 ###

*  Spring Cloud 项目关键点
 *   *   *  父 pom.xml
         *  eureka-server
         *   *   *  pom.xml
                 *  application.yml
                 *  code
         *  Service-Provider : USER
         *   *   *  pom.xml
                 *  application.yml
                 *  code
         *  Service-Consumer: ORDER
         *   *   *  pom.xml
                 *  application.yml
                 *  code
     *  更多 ...
     *   *  Service
         *   *   *  pom.xml
                 *  application.yml
                 *  code

### 父 pom.xml ###

<dependencyManagement>
            <dependencies>
                <dependency>
                    <groupId>org.springframework.cloud</groupId>
                    <artifactId>spring-cloud-dependencies</artifactId>
                    <version>Greenwich.SR1</version>
                    <type>pom</type>
                    <scope>import</scope>
                </dependency>
                <dependency>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-dependencies</artifactId>
                    <version>2.1.2.RELEASE</version>
                    <type>pom</type>
                    <scope>import</scope>
                </dependency>
            </dependencies>
        </dependencyManagement>

### eureka-server ###

##### pom.xml #####

<dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-starter-netflix-eureka-server</artifactId>
            </dependency>

##### application.yml #####

server:
      port: 10000
    spring:
      application:
        name: EUREKA-SERVER
      #security:
        #user:
          #password: 123
    eureka:
      client:
        service-url:
          defaultZone: http://user:123@localhost:10000/eureka # 必须写对
        register-with-eureka: false
        fetch-registry: false
      instance:
        prefer-ip-address: true

##### code #####

@SpringBootApplication
    @EnableEurekaServer
    public class EurekaApp { 
        public static void main(String[] args){ 
            SpringApplication.run(EurekaApp.class, args);
        }
    }

--------------------

### Service-Provider : USER ###

##### pom.xml #####

<dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-web</artifactId>
            </dependency>
            <dependency>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
            </dependency>

##### application.yml #####

server:
      port: 7900
    spring:
      application:
        name: USER
    eureka:
      client:
        serviceUrl:
          defaultZone: http://user:123@localhost:10000/eureka/

##### code #####

@RestController
    public class UserApi { 
    
        @Autowired
        private EurekaClient eurekaClient;
    
        @RequestMapping("user/{id}")
        public User findById(@PathVariable  Integer id){ 
            return new User(id, UUID.randomUUID().toString());
        }
    
        @PostMapping("show")
        public User show(User user){ 
            return user;
        }
    
        @RequestMapping("info")
        public String eurekaInfo(){ 
            InstanceInfo instanceInfo = eurekaClient.getNextServerFromEureka("ORDER", false);
            return instanceInfo.getHomePageUrl();
        }
    }

--------------------

### Service-Consumer: ORDER ###

##### pom.xml #####

<dependencies>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-web</artifactId>
            </dependency>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
            </dependency>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-starter-netflix-ribbon</artifactId>
            </dependency>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-starter-openfeign</artifactId>
            </dependency>
        </dependencies>

##### application.yml #####

server:
      port: 7901
    spring:
      application:
        name: ORDER
    eureka:
      client:
        serviceUrl:
          defaultZone: http://user:123@localhost:10000/eureka/

##### code #####

主类添加注解：

@SpringBootApplication
    @EnableFeignClients

Controller 使用 Feign 服务调用

@RestController
    public class OrderApi { 
    
    /*// Ribbon 形式 @Autowired RestTemplate restTemplate; @RequestMapping("{id}") User findById(@PathVariable Integer id){ User u = restTemplate.getForObject("http://USER/user/" + id, User.class); return u; }*/
    	// Feign 形式
        @Autowired
        private UserRemoteAPI userRemoteAPI;
    
        @RequestMapping("order/{id}")
        User findById(@PathVariable Integer id){ 
            User u = userRemoteAPI.findById(id);
            return u;
        }
    
        @RequestMapping("info")
        String eurekaInfo (){ 
            return userRemoteAPI.eurekaInfo();
        }
    
        @RequestMapping("show")
        User show (){ 
            return userRemoteAPI.showUser(new User(0, "testFeign"));
        }
    
    }

若使用 Ribbon 需要代码：

@Configuration
    @RibbonClient("USER") //使用Ribbon形式，替换ip+port形式访问
    public class RestTemplateConfig { 
    
        @Bean	// RestTemplate 必须
        @LoadBalanced // 开启 Ribbon 进行负载均衡（默认通过 Eureaka 轮询）
        public RestTemplate restTemplateBean(){ 
            return new RestTemplate();
        }
    }

若使用 Feign 需要代码：

@FeignClient("USER")	// 使用 Feign 来访问 USER 服务
    @Component
    public interface UserRemoteAPI { 
    
        @GetMapping(value = "user/{id}")
        User findById(@PathVariable("id") Integer id);
    
        @RequestMapping("info")
        String eurekaInfo();
    
        @PostMapping("show")
        User showUser(User user);//传递复杂参数只能是 POST 方式，无论你怎么配，feign总是通过 POST 方式
    }

--------------------

## 更多 … ##

### Service ###

##### pom.xml #####

##### application.yml #####

##### code #####