第一个Hystrix程序 Hystrix 一-优快云博客

本文详细介绍了如何使用Hystrix断路器处理服务调用中的异常情况，包括导入必要的jar包，编写正常和异常情况下的HystrixCommand，以及实现回退方法。通过示例展示了如何创建HystrixCommand并执行，同时提供了服务接口的实现。

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1.导入jar包

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

    <dependency>
      <groupId>org.slf4j</groupId>
      <artifactId>slf4j-log4j12</artifactId>
      <version>1.7.25</version>
    </dependency>

    <dependency>
      <groupId>commons-logging</groupId>
      <artifactId>commons-logging</artifactId>
      <version>1.2</version>
    </dependency>

    <dependency>
      <groupId>org.apache.httpcomponents</groupId>
      <artifactId>httpclient</artifactId>
      <version>4.5.5</version>
    </dependency>
  </dependencies>

2.编写hystrix测试类

（1）正常情况

import com.netflix.hystrix.HystrixCommand;
import com.netflix.hystrix.HystrixCommandGroupKey;
import org.apache.http.HttpResponse;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.util.EntityUtils;

public class HelloCommand extends HystrixCommand<String> {

    protected HelloCommand() {
        super(HystrixCommandGroupKey.Factory.asKey("TestGroup"));
    }

    @Override
    protected String run() throws Exception {
        String url = "http://localhost:8080/test/hello";
        HttpGet httpGet = new HttpGet(url);
        CloseableHttpClient httpClient = HttpClients.createDefault();
        HttpResponse response = httpClient.execute(httpGet);
        String result = EntityUtils.toString(response.getEntity());
        return result;
    }
}

（2）异常情况

import com.netflix.hystrix.HystrixCommand;
import com.netflix.hystrix.HystrixCommandGroupKey;
import org.apache.http.HttpResponse;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.util.EntityUtils;

public class HelloErrorCommand extends HystrixCommand<String> {

    protected HelloErrorCommand() {
        super(HystrixCommandGroupKey.Factory.asKey("TestGroup"));
    }

    @Override
    protected String run() throws Exception {
        String url = "http://localhost:8080/test/erroHello";
        HttpGet httpGet = new HttpGet(url);
        CloseableHttpClient httpClient = HttpClients.createDefault();
        HttpResponse response = httpClient.execute(httpGet);
        String result = EntityUtils.toString(response.getEntity());
        return result;
    }

    @Override
    protected String getFallback() {
        System.out.println("这是回退方法");
        return "回退方法";
    }
}

（3）测试方法

public class HelloMain {
    public static void main(String[] args) {
        HelloCommand command = new HelloCommand();
        String result = command.execute();
        System.out.println(result);

        HelloErrorCommand command1 = new HelloErrorCommand();
        String result1 = command1.execute();
        System.out.println(result1);
    }
}

3.服务接口

　　@GetMapping(value = "/hello")
    public String hello() {
        return "hello world";
    }

    @GetMapping(value = "/erroHello")
    public String erroHello() throws Exception{
        Thread.sleep(10000);
        return "hello error";
    }