Hystrix-快速开始

最新推荐文章于 2024-09-28 12:41:44 发布

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最新推荐文章于 2024-09-28 12:41:44 发布

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分类专栏： spring cloud 文章标签： spring cloud hystrix 熔断器

本文链接：https://blog.youkuaiyun.com/u010327957/article/details/87804941

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本文介绍如何使用Hystrix熔断器处理接口调用中的异常和超时问题，包括配置Maven依赖、创建命令类、实现正常与错误接口调用的示例。

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Hystrix-快速开始

接口提供者编写

Pom文件

<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>
	<groupId>org.crazyit.cloud</groupId>
	<artifactId>first-hy-server</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	
	<dependencies>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-web</artifactId>
			<version>1.5.4.RELEASE</version>
		</dependency>
	</dependencies>
	
</project>

项目启动类

package org.crazyit.cloud;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.ComponentScan;

@SpringBootApplication
public class MyApplication {

	public static void main(String[] args) {
		SpringApplication.run(MyApplication.class, args);
	}

}

被调用的接口代码

package org.crazyit.cloud;

import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class MyController {

	@RequestMapping(value = "/normalHello", method = RequestMethod.GET)
	public String normalHello() {
		return "Hello World";
	}

	@RequestMapping(value = "/errorHello", method = RequestMethod.GET)
	public String errorHello() throws Exception {
		Thread.sleep(10000);
		return "Error Hello World";
	}
}

/errorHello，异常情况，此请求需要10秒才能处理完毕。

/normalHello，正常情况，处理快速。

运行MyApplication的main方法，使接口可以被调用。

接口调用者编写

Hystrix是在接口调用方的技术，故hystrix的相关代码如下

Pom文件-引入相关依赖

<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>
	<groupId>org.crazyit.cloud</groupId>
	<artifactId>first-hy-client</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	
	<dependencies>
		<dependency>
			<groupId>com.netflix.hystrix</groupId>
			<artifactId>hystrix-core</artifactId>
			<version>1.5.12</version>
		</dependency>
		<dependency>
			<groupId>org.slf4j</groupId>
			<artifactId>slf4j-api</artifactId>
			<version>1.7.7</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>4.5.2</version>
		</dependency>
	</dependencies>
	
</project>

引入com.netflix.hystrix的core包

调用正常接口代码

编写命令类

package org.crazyit.cloud;

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;

import com.netflix.hystrix.HystrixCommand;
import com.netflix.hystrix.HystrixCommandGroupKey;

public class HelloCommand extends HystrixCommand<String> {

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

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

}

编写main方法执行命令

package org.crazyit.cloud;

public class NormalMain {

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

}

编写命令类：执行错误命令的命令类

package org.crazyit.cloud.error;

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;

import com.netflix.hystrix.HystrixCommand;
import com.netflix.hystrix.HystrixCommandGroupKey;

public class ErrorCommand extends HystrixCommand<String> {

	public ErrorCommand() {
		super(HystrixCommandGroupKey.Factory.asKey("TestGroup"));
	}

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

	@Override
	protected String getFallback() {
		System.out.println("fall back method");
		return "fall back hello";
	}
	
	
}

编写main方法执行命令

package org.crazyit.cloud.error;

public class ErrorMain {

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

}