1.SpringCloud微服务框架
a.概念：SpringCloud是基于SpringBoot的微服务框架
b.五大神兽：Eureka（服务发现）、Ribbon（客服端负载均衡）、Hystrix（断路器）、Zuul（服务网关）、Spring Cloud Config（分布式配置）
2.Eureka服务发现
a.组成：Eureka服务器和Eureka客户端
b.Eureka服务器（注册中心）
①新建springboot项目，依赖选择Eureka Server
②pom文件关键依赖
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.1.3.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent> <dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-netflix-eureka-server</artifactId>
</dependency> ...... </dependencies> ......
③application.yml文件
# 服务名称
spring:
application:
name: eureka-server
# 服务端口号
server:
port: 8081 #Eureka 相关配置
eureka:
instance:
hostname: localhost
client:
service-url:
defaultZone: http://localhost:${server.port}/eureka/
# 是否从其他的服务中心同步服务列表
fetch-registry: false
# 是否把自己作为服务注册到其他服务注册中心
register-with-eureka: false
④启动类添加注解@EnableEurekaServer
@SpringBootApplication
@EnableEurekaServer
public class EurekaServerApplication { public static void main(String[] args) {
SpringApplication.run(EurekaServerApplication.class, args);
} }
⑤启动后访问 localhost:8081 可进入管理员界面
c.Eureka客户端（生产者）
①新建springboot项目，依赖选择 Eureka Discovery 、Web
②pom文件关键依赖
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.1.3.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent> <dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
</dependency> ...... </dependencies> ......
③application.yml文件
spring:
application:
name: eureka-client-producer
server:
port: 8082 eureka:
client:
service-url:
defaultZone: http://localhost:8081/eureka/
④启动类添加注解@EnableEurekaClient
@SpringBootApplication
@EnableEurekaClient
public class EurekaClientProducerApplication { public static void main(String[] args) {
SpringApplication.run(EurekaClientProducerApplication.class, args);
} }
⑤创建controller供外部调用
@RestController
public class CommonController { @Value("${server.port}")
String port; @Value("${spring.application.name}")
String name; @RequestMapping(value = "/printProducer")
public String printProducer(String param){
return "[" + name + "]请求参数：" + param + "，服务端口：" + port;
}
}
3.Ribbon负载均衡
a.Eureka客户端(消费者) + Ribbon负载均衡
①新建springboot项目，依赖选择 Eureka Discovery 、Web 以及 Ribbon
②pom文件关键依赖
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.1.3.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-netflix-eureka-client</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-netflix-ribbon</artifactId>
</dependency> ...... </dependencies> ......
③application.yml文件
spring:
application:
name: eureka-client-consumer
server:
port: 8085 eureka:
client:
service-url:
defaultZone: http://localhost:8081/eureka/
④启动类添加注解@EnableDiscoveryClient并且加入restTemplate
@SpringBootApplication
@EnableEurekaClient
public class EurekaClientConsumerApplication { public static void main(String[] args) {
SpringApplication.run(EurekaClientConsumerApplication.class, args);
} @Bean
@LoadBalanced
RestTemplate restTemplate()
{
return new RestTemplate();
} }
⑤使用restTemplate调用服务
@RestController
public class CommonController { @Resource
RestTemplate restTemplate; @RequestMapping(value = "/print")
public String print(String param){
String result = restTemplate.getForObject("http://EUREKA-CLIENT-PRODUCER/printProducer?param=" + param, String.class);
return result;
} }
4.Hystrix断路器
a.消费者增加Hystrix依赖，pom中添加
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-netflix-hystrix</artifactId>
</dependency>
b.启动类添加注解@EnableHystrix
@SpringBootApplication
@EnableEurekaClient
@EnableHystrix
public class EurekaClientConsumerApplication { ...... }
c.具体使用
@RestController
public class CommonController { @Resource
RestTemplate restTemplate; /* 断路器配置，当无法调用如下方法时，就会调用自定的errorCallback方法。 */
@HystrixCommand(fallbackMethod = "errorCallback")
@RequestMapping(value = "/print")
public String print(String param){
String result = restTemplate.getForObject("http://EUREKA-CLIENT-PRODUCER/printProducer?param=" + param, String.class);
return result;
} public String errorCallback(String param){
return "连接消费服务失败，请求参数：" + param;
} }