续：

《》

《》

《》

Hystrix使用

1 package com.cjs.example; 2  3 import com.netflix.hystrix.HystrixCommand; 4 import com.netflix.hystrix.HystrixCommandGroupKey; 5  6 public class CommandHelloWorld extends HystrixCommand
     
       { 7  8     private String name; 9 10     public CommandHelloWorld(HystrixCommandGroupKey group, String name) {11         super(group);12         this.name = name;13     }14 15     public CommandHelloWorld(Setter setter, String name) {16         super(setter);17         this.name = name;18     }19 20     @Override21     protected String run() throws Exception {22         if ("Alice".equals(name)) {23             throw new RuntimeException("出错了");24         }25         return "Hello, " + name;26     }27 28     @Override29     protected String getFallback() {30         return "Failure, " + name;31     }32 33 }
     

1 package com.cjs.example; 2  3 import com.netflix.hystrix.HystrixCommand; 4 import com.netflix.hystrix.HystrixCommandGroupKey; 5 import com.netflix.hystrix.HystrixCommandProperties; 6 import com.netflix.hystrix.HystrixThreadPoolProperties; 7 import org.junit.Test; 8 import rx.Observable; 9 import rx.Observer;10 11 import java.util.concurrent.ExecutionException;12 import java.util.concurrent.Future;13 14 import static org.junit.Assert.*;15 import static org.junit.Assert.assertEquals;16 17 public class CommandHelloWorldTest {18 19     @Test20     public void testSync() {21         HystrixCommandGroupKey hystrixCommandGroupKey = HystrixCommandGroupKey.Factory.asKey("ExampleGroup");22         CommandHelloWorld command = new CommandHelloWorld(hystrixCommandGroupKey, "World");23         String result = command.execute();24         assertEquals("Hello, World", result);25     }26 27     @Test28     public void testAsync() throws ExecutionException, InterruptedException {29         HystrixCommandGroupKey groupKey = HystrixCommandGroupKey.Factory.asKey("ExampleGroup");30         assertEquals("Hello, Jack", new CommandHelloWorld(groupKey, "Jack").queue().get());31         assertEquals("Hello, Rose", new CommandHelloWorld(groupKey, "Rose").queue().get());32 33         CommandHelloWorld command = new CommandHelloWorld(groupKey, "Cheng");34         Future
     
       future = command.queue();35         String result = future.get();36         assertEquals("Hello, Cheng", result);37 38         //  blocking39         Observable
      
        observable = new CommandHelloWorld(groupKey, "Lucy").observe();40         assertEquals("Hello, Lucy", observable.toBlocking().single());41 42         //  non-blocking43         Observable
       
         observable2 = new CommandHelloWorld(groupKey, "Jerry").observe();44         observable2.subscribe(new Observer
        
         () {45             @Override46             public void onCompleted() {47                 System.out.println("completed");48             }49 50             @Override51             public void onError(Throwable throwable) {52                 throwable.printStackTrace();53             }54 55             @Override56             public void onNext(String s) {57                 System.out.println("onNext: " + s);58             }59         });60     }61 62     @Test63     public void testFail() throws ExecutionException, InterruptedException {64         HystrixCommandGroupKey groupKey = HystrixCommandGroupKey.Factory.asKey("Group2");65         assertEquals("Failure, Alice", new CommandHelloWorld(groupKey,"Alice").execute());66         assertEquals("Failure, Alice", new CommandHelloWorld(groupKey,"Alice").queue().get());67     }68 69     @Test70     public void testProp() {71         HystrixCommandGroupKey groupKey = HystrixCommandGroupKey.Factory.asKey("Group3");72 73         HystrixThreadPoolProperties.Setter threadPoolProperties = HystrixThreadPoolProperties.Setter()74                 .withCoreSize(10)75                 .withMaximumSize(10);76 77         HystrixCommandProperties.Setter commandProperties = HystrixCommandProperties.Setter()78                 .withCircuitBreakerEnabled(true)79                 .withExecutionTimeoutInMilliseconds(100);80 81         HystrixCommand.Setter setter = HystrixCommand.Setter.withGroupKey(groupKey);82         setter.andThreadPoolPropertiesDefaults(threadPoolProperties);83         setter.andCommandPropertiesDefaults(commandProperties);84 85         assertEquals("Hello, Cheng", new CommandHelloWorld(setter, "Cheng").execute());86 87     }88 }
        
       
      
     

Spring Boot中使用Hystrix

1. Maven依赖

2. 使用@HystrixCommand注解

1 package com.cjs.example; 2  3 import com.netflix.hystrix.contrib.javanica.annotation.HystrixCommand; 4 import com.netflix.hystrix.contrib.javanica.annotation.HystrixProperty; 5 import org.apache.commons.lang.StringUtils; 6 import org.springframework.web.bind.annotation.RequestMapping; 7 import org.springframework.web.bind.annotation.RestController; 8  9 @RestController10 @RequestMapping("/greet")11 public class GreetController {12 13     @HystrixCommand(fallbackMethod = "onError",14             commandProperties = {15                     @HystrixProperty(name = "execution.isolation.strategy", value = "THREAD"),16                     @HystrixProperty(name = "execution.isolation.thread.timeoutInMilliseconds", value = "1000"),17                     @HystrixProperty(name = "circuitBreaker.enabled", value = "true"),18                     @HystrixProperty(name = "circuitBreaker.requestVolumeThreshold", value = "2")},19             threadPoolProperties = {20                     @HystrixProperty(name = "coreSize", value = "5"),21                     @HystrixProperty(name = "maximumSize", value = "5"),22                     @HystrixProperty(name = "maxQueueSize", value = "10")23             })24     @RequestMapping("/sayHello")25     public String sayHello(String name) {26         try {27             Thread.sleep(200);28         } catch (InterruptedException e) {29             e.printStackTrace();30         }31         return "Hello, " + name;32     }33 34     @HystrixCommand35     @RequestMapping("/sayHi")36     public String sayHi(String name) {37         if (StringUtils.isBlank(name)) {38             throw new RuntimeException("name不能为空");39         }40         return "Good morning, " + name;41     }42 43     /**44      * 如果fallback方法的参数和原方法参数个数不一致，则会出现FallbackDefinitionException: fallback method wasn't found45      */46     public String onError(String name) {47         return "Error!!!" + name;48     }49 50 }

3. Hystrix配置

1 package com.cjs.example; 2  3 import com.netflix.hystrix.contrib.javanica.annotation.HystrixCommand; 4 import com.netflix.hystrix.contrib.javanica.aop.aspectj.HystrixCommandAspect; 5 import com.netflix.hystrix.contrib.metrics.eventstream.HystrixMetricsStreamServlet; 6 import org.springframework.boot.web.servlet.ServletContextInitializer; 7 import org.springframework.boot.web.servlet.ServletRegistrationBean; 8 import org.springframework.context.annotation.Bean; 9 import org.springframework.context.annotation.Configuration;10 11 import javax.servlet.Servlet;12 13 @Configuration14 public class HystrixConfig {15 16     /**17      * A {
    @link ServletContextInitializer} to register {
    @link Servlet}s in a Servlet 3.0+ container.18      */19     @Bean20     public ServletRegistrationBean hystrixMetricsStreamServlet() {21         return new ServletRegistrationBean(new HystrixMetricsStreamServlet(), "/hystrix.stream");22     }23 24     /**25      * AspectJ aspect to process methods which annotated with {
    @link HystrixCommand} annotation.26      *27      * {
    @link HystrixCommand} annotation used to specify some methods which should be processes as hystrix commands.28      */29     @Bean30     public HystrixCommandAspect hystrixCommandAspect() {31         return new HystrixCommandAspect();32     }33 34 }

4. hystrix-dashboard

http://localhost:7979/hystrix-dashboard/

 

参考