第八章 SpringCloud之Feign、Hystrix结合使用
#这个章节主要是针对Hystrix的使用,因为Feign的章节在上一节已经实现了,整个代码也是在上一个章节的基础上修改的
##################Hystrix一个简单Demo实现#######################
1、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>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>2.1.3.RELEASE</version> <relativePath/> <!-- lookup parent from repository --> </parent> <groupId>com.test</groupId> <artifactId>eureka-client-feign-hystrix</artifactId> <version>0.0.1-SNAPSHOT</version> <name>eureka-client-feign-hystrix</name> <description>Demo project for Spring Boot</description> <properties> <java.version>1.8</java.version> <spring-cloud.version>Greenwich.SR1</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-server</artifactId> </dependency> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-openfeign</artifactId> </dependency> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-netflix-hystrix</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-test</artifactId> <scope>test</scope> </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>
2、application.yml文件配置
spring:
application:
name: eureka-client-feign-hystrix #应用名
logging: #logging日志配置
level:
root: INFO
org.hibernate: INFO
server:
port: 8667 #服务端口
eureka:
instance:
hostname: localhost
prefer-ip-address: true
instance-id: ${spring.application.name}:${spring.application.instance_id:${server.port}}
client:
serviceUrl:
defaultZone: http://${eureka.instance.hostname}:8661/eureka
3、启动类加配置
package com.test.eurekaclientfeign; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; import org.springframework.cloud.client.circuitbreaker.EnableCircuitBreaker; import org.springframework.cloud.openfeign.EnableFeignClients; @SpringBootApplication @EnableFeignClients @EnableCircuitBreaker public class EurekaClientFeignHystrixApplication { public static void main(String[] args) { SpringApplication.run(EurekaClientFeignHystrixApplication.class, args); } }
4、User.java类
package com.test.eurekaclientfeign.entity; import java.io.Serializable; import java.math.BigDecimal; public class User implements Serializable { private Long id; private String name; private String username; private BigDecimal balance; private short age; public Long getId() { return id; } public void setId(Long id) { this.id = id; } public String getName() { return name; } public void setName(String name) { this.name = name; } public String getUsername() { return username; } public void setUsername(String username) { this.username = username; } public BigDecimal getBalance() { return balance; } public void setBalance(BigDecimal balance) { this.balance = balance; } public short getAge() { return age; } public void setAge(short age) { this.age = age; } }
5、自定义UserFeignClientConfig.java类,该类的使用,表示不使用Feign的默认配置
package com.test.eurekaclientfeign.feign; import feign.Logger; import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.Configuration; @Configuration public class UserFeignClientConfig { /* @Bean public Contract feignContract() { return new feign.Contract.Default(); }*/ @Bean Logger.Level feignLoggerLevel() { return Logger.Level.FULL; } }
6、UserFeignClient1.java
package com.test.eurekaclientfeign.feign; import com.test.eurekaclientfeign.entity.User; import org.springframework.cloud.openfeign.FeignClient; import org.springframework.web.bind.annotation.PathVariable; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RequestMethod; @FeignClient(name = "eureka-client-user", configuration = UserFeignClientConfig.class) public interface UserFeignClient1 { @RequestMapping(method = RequestMethod.GET, value = "/user/{id}") User findById(@PathVariable("id") Long id); }
7、MovieController.java类,实现远程调用的类
package com.test.eurekaclientfeign.controller; import com.netflix.hystrix.contrib.javanica.annotation.HystrixCommand; import com.test.eurekaclientfeign.entity.User; import com.test.eurekaclientfeign.feign.UserFeignClient1; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.web.bind.annotation.GetMapping; import org.springframework.web.bind.annotation.PathVariable; import org.springframework.web.bind.annotation.RestController; @RestController public class MovieController { @Autowired(required = true) private UserFeignClient1 userFeignClient1; @GetMapping(value = "/hystrix/{id}") @HystrixCommand(fallbackMethod = "defaultMethod") //一但无法调用远程的findById(),则会调用Hystrix的默认接口defaultMethod(),其参数要一致,否则无法使用 public User findById(@PathVariable("id") Long id) { return this.userFeignClient1.findById(id); } public User defaultMethod(@PathVariable("id") Long id){ User user = new User(); user.setId(id); user.setName("hystrix"); return user; } }
8、URL访问
http://localhost:8661/ # 服务发现 http://192.168.137.1:8667/hystrix/9 #实现断路,因为数据库没有id=9的数据 http://192.168.137.1:8667/hystrix/1 #可以正常访问
Hystrix访问实现如下:
########Hystrix将调用访问和断路执行方法绑定在一个线程#########
只需在MovieController.java中的HystrixCommand添加一个commandProperties属性即可,如下
package com.test.eurekaclientfeign.controller; import com.netflix.hystrix.contrib.javanica.annotation.HystrixCommand; import com.netflix.hystrix.contrib.javanica.annotation.HystrixProperty; import com.test.eurekaclientfeign.entity.User; import com.test.eurekaclientfeign.feign.UserFeignClient1; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.web.bind.annotation.GetMapping; import org.springframework.web.bind.annotation.PathVariable; import org.springframework.web.bind.annotation.RestController; @RestController public class MovieController { @Autowired(required = true) private UserFeignClient1 userFeignClient1; @GetMapping(value = "/hystrix/{id}") @HystrixCommand(fallbackMethod = "defaultMethod", commandProperties = { @HystrixProperty(name="execution.isolation.strategy", value="SEMAPHORE") } ) //一但无法调用远程的findById(),则会调用Hystrix的默认接口defaultMethod(),其参数要一致,否则无法使用 //添加commandProperties属性,可以使得findById()和defaultMethod()绑定到一个线程中 public User findById(@PathVariable("id") Long id) { return this.userFeignClient1.findById(id); } public User defaultMethod(@PathVariable("id") Long id){ User user = new User(); user.setId(id); user.setName("hystrix"); return user; } }
###########Hystrix健康检查与监控################
1、在pom.xml再添加下面依赖
<dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-actuator</artifactId> </dependency>
2、在启动类添加一个Bean
package com.test.eurekaclientfeign; import com.netflix.hystrix.contrib.metrics.eventstream.HystrixMetricsStreamServlet; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; import org.springframework.boot.web.servlet.ServletRegistrationBean; import org.springframework.cloud.client.circuitbreaker.EnableCircuitBreaker; import org.springframework.cloud.openfeign.EnableFeignClients; import org.springframework.context.annotation.Bean; @SpringBootApplication @EnableFeignClients @EnableCircuitBreaker public class EurekaClientFeignHystrixApplication { public static void main(String[] args) { SpringApplication.run(EurekaClientFeignHystrixApplication.class, args); } @Bean public ServletRegistrationBean getServlet(){ HystrixMetricsStreamServlet streamServlet = new HystrixMetricsStreamServlet(); ServletRegistrationBean registrationBean = new ServletRegistrationBean(streamServlet); registrationBean.setLoadOnStartup(1); registrationBean.addUrlMappings("/actuator/hystrix.stream"); registrationBean.setName("HystrixMetricsStreamServlet"); return registrationBean; } }
3、启动Eureka和服务程序,访问远程调用的服务程序,执行下面的URL
#使用了actuator,所以都必须以这个组件开始 http://localhost:8667/actuator/hystrix.stream http://localhost:8667/actuator/health
本文来自博客园,作者:小白啊小白,Fighting,转载请注明原文链接:https://www.cnblogs.com/ywjfx/p/10556521.html