Spring Boot 集成 Hystrix

2018-08-02 05:53:43来源：博客园阅读 ()

续：

《Hystrix介绍》

《Hystrix是如何工作的》

《SpringCloud学习笔记(3)——Hystrix》

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<String> {
 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     @Override
21     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     @Override
29     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     @Test
20     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     @Test
28     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<String> future = command.queue();
35         String result = future.get();
36         assertEquals("Hello, Cheng", result);
37 
38         //  blocking
39         Observable<String> observable = new CommandHelloWorld(groupKey, "Lucy").observe();
40         assertEquals("Hello, Lucy", observable.toBlocking().single());
41 
42         //  non-blocking
43         Observable<String> observable2 = new CommandHelloWorld(groupKey, "Jerry").observe();
44         observable2.subscribe(new Observer<String>() {
45             @Override
46             public void onCompleted() {
47                 System.out.println("completed");
48             }
49 
50             @Override
51             public void onError(Throwable throwable) {
52                 throwable.printStackTrace();
53             }
54 
55             @Override
56             public void onNext(String s) {
57                 System.out.println("onNext: " + s);
58             }
59         });
60     }
61 
62     @Test
63     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     @Test
70     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 @RestController
10 @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     @HystrixCommand
35     @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 found
45      */
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 @Configuration
14 public class HystrixConfig {
15 
16     /**
17      * A {@link ServletContextInitializer} to register {@link Servlet}s in a Servlet 3.0+ container.
18      */
19     @Bean
20     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     @Bean
30     public HystrixCommandAspect hystrixCommandAspect() {
31         return new HystrixCommandAspect();
32     }
33 
34 }