搭建三个工程eureka-server，hello-service，hystrix-service。
eureka-server搭建，pom.xml文件如下：
<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.2.8.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<groupId>com.hangzhou.springcloud</groupId>
<artifactId>eureka-server</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>eureka-server</name>
<description>Demo project for Spring Boot</description>
<properties>
<java.version>1.8</java.version>
<spring-cloud.version>Hoxton.SR6</spring-cloud.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-netflix-eureka-server</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
<exclusions>
<exclusion>
<groupId>org.junit.vintage</groupId>
<artifactId>junit-vintage-engine</artifactId>
</exclusion>
</exclusions>
</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>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
application.properties文件如下：
# 指定运行端口号
server.port=1111
# 指定服务名称
spring.applcation.name=eureka-server
# 指定本机地址
eureka.instance.hostname=localhost
# 指定是否将服务注册到注册中心（注册中心不需要开启）
eureka.client.register-with-eureka=false
# 指定是否从注册中心获取服务(注册中心不需要开启)
eureka.client.fetch-registry=false
程序启动类，编写如下：
@EnableEurekaServer
@SpringBootApplication
public class EurekaServerApplication {
public static void main(String[] args) {
SpringApplication.run(EurekaServerApplication.class, args);
}
}
自此注册中心搭建完毕。
hello-service搭建开始，pom.xml文件如下：
<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.2.8.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<groupId>com.hangzhou.springcloud</groupId>
<artifactId>hello-service</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>hello-service</name>
<description>Demo project for Spring Boot</description>
<properties>
<java.version>1.8</java.version>
<spring-cloud.version>Hoxton.SR6</spring-cloud.version>
</properties>
<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.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
<exclusions>
<exclusion>
<groupId>org.junit.vintage</groupId>
<artifactId>junit-vintage-engine</artifactId>
</exclusion>
</exclusions>
</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>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
application.properties文件如下：
# 指定运行端口号
server.port=1112
# 指定服务名称
spring.application.name=hello-service
# 指定本机地址
eureka.instance.hostname=localhost
# 指定是否将服务注册到注册中心（注册中心不需要开启）
eureka.client.register-with-eureka=true
# 指定是否从注册中心获取服务(注册中心不需要开启)
eureka.client.fetch-registry=true
# 配置注册中心地址
eureka.client.service-url.defaultZone=http://localhost:1111/eureka
程序启动类，如下所示：
@EnableDiscoveryClient
@SpringBootApplication
public class HelloServiceApplication {
public static void main(String[] args) {
SpringApplication.run(HelloServiceApplication.class, args);
}
}
controller类中，加入睡眠方便实现服务降级效果。
@RequestMapping("/test")
@RestController
public class HelloController {
@GetMapping(value="/hello")
public String hello() throws InterruptedException {
System.out.println("进入helloword");
new Thread().sleep(5000);
return "hello word";
}
}
自此服务提供者搭建完毕，下面我们来搭建hystrix.service，pom.xml文件如下：
<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.2.8.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<groupId>com.hangzhou.springcloud</groupId>
<artifactId>hystrix-service</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>hystrix-service</name>
<description>Demo project for Spring Boot</description>
<properties>
<java.version>1.8</java.version>
<spring-cloud.version>Hoxton.SR6</spring-cloud.version>
</properties>
<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-hystrix</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-openfeign</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
<exclusions>
<exclusion>
<groupId>org.junit.vintage</groupId>
<artifactId>junit-vintage-engine</artifactId>
</exclusion>
</exclusions>
</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>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
application.properties文件如下：
# 指定运行端口号
server.port=1116
# 服务名称
spring.application.name=hystrix-service
eureka.client.fetch-registry=true
eureka.client.register-with-eureka=true
eureka.client.service-url.defaultZone=http://localhost:1111/eureka/
程序启动类代码如下：
@EnableCircuitBreaker
@EnableFeignClients
@EnableDiscoveryClient
@SpringBootApplication
public class HystrixServiceApplication {
public static void main(String[] args) {
SpringApplication.run(HystrixServiceApplication.class, args);
}
}
feign客户端调用工具如下：
//此value值与服务提供者的spring.application.name的值是一致的
@FeignClient(value = "hello-service")
public interface HelloService {
//服务提供者的全路径访问(不包括http://localhost:1112)
@GetMapping(value="/test/hello")
public String hello();
}
controller类如下所示：
@RestController
@RequestMapping("/hystrix")
public class HystrixController {
@Autowired
private HelloService helloService;
@RequestMapping("/hello")
@HystrixCommand(fallbackMethod = "testHello")
public String hello() {
return helloService.hello();
}
public String testHello() {
return "服务调用不通过,服务降级";
}
}
搭建完毕，依次启动项目eureka-server，hello-servic，hystrix-service目录，游览器输入http://localhost:1116/hystrix/hello,效果如下图所示：
