<dependency><groupId>com.netflix.hystrix</groupId><artifactId>hystrix-core</artifactId><version>1.5.12</version></dependency>

import com.netflix.hystrix.HystrixCommand;
import com.netflix.hystrix.HystrixCommandGroupKey;
import com.netflix.hystrix.HystrixCommandProperties;import java.util.concurrent.TimeUnit;/*** 使用HystrixCommand封装执行方法。继承Hystrix命令基类，泛型参数即调用方法的返回参数*/
public class HelloWorldCommand extends HystrixCommand<String>
{private final String name;/*** 定义构造函数，参数即被包装方法的输入参数* @param name*/public HelloWorldCommand(String name){//定义命令组 和 方法调用超时时间super(Setter.withGroupKey(HystrixCommandGroupKey.Factory.asKey("HelloWorldGroup")).andCommandPropertiesDefaults(HystrixCommandProperties.Setter().withExecutionTimeoutInMilliseconds(5000)));this.name = name;}/*** 封装业务逻辑的方法体，在这里执行真正的业务逻辑。* @return* @throws Exception*/@Overrideprotected String run() throws Exception{//例子中，模拟执行超时if (name.equals("TimeoutCommand")){TimeUnit.SECONDS.sleep(6);}//例子中，模拟出现异常if (name.equals("ExceptionCommand")){throw new Exception("ExceptionCommand");}//例子中，模拟正常返回return "Hello " + name + "!";}/*** 降级方法定义，即，run方法中出现异常后应该执行的方法。包括例子中的超时。* @return*/@Overrideprotected String getFallback(){return "Command failed!";}
}

public class HelloWorld
{public static void main(String[] args){SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");String s = new HelloWorldCommand("Nick").execute();System.out.println(sdf.format(new Date()) + "->" + s);s = new HelloWorldCommand("TimeoutCommand").execute();System.out.println(sdf.format(new Date()) + "->" + s);s = new HelloWorldCommand("ExceptionCommand").execute();System.out.println(sdf.format(new Date()) + "->" + s);}
}

2017-12-24 17:58:18->Hello Nick!
2017-12-24 17:58:23->Command failed!
2017-12-24 17:58:23->Command failed!