# 090. 基于 hystrix 的线程池隔离技术进行商品服务接口的资源隔离

package cn.mrcode.cachepdp.eshop.cache.ha.hystrix.command;

import com.alibaba.fastjson.JSON;
import com.netflix.hystrix.HystrixCommand;
import com.netflix.hystrix.HystrixCommandGroupKey;
import com.netflix.hystrix.HystrixCommandProperties;
import com.netflix.hystrix.HystrixThreadPoolProperties;

import java.util.concurrent.TimeUnit;

import cn.mrcode.cachepdp.eshop.cache.ha.http.HttpClientUtils;
import cn.mrcode.cachepdp.eshop.cache.ha.model.ProductInfo;

/**
 * ${todo}
 *
 * @author : zhuqiang
 * @date : 2019/6/1 23:45
 */
public class GetProductCommand extends HystrixCommand<ProductInfo> {
    private Long productId;

    public GetProductCommand(Long productId) {
//        super(HystrixCommandGroupKey.Factory.asKey("GetProductCommandGroup"));
        // 线程组名
        super(Setter.withGroupKey(HystrixCommandGroupKey.Factory.asKey("GetProductCommandGroup"))
                // 超时时间
                .andCommandPropertiesDefaults(HystrixCommandProperties.Setter().withExecutionTimeoutInMilliseconds(6000))
                .andThreadPoolPropertiesDefaults(HystrixThreadPoolProperties.Setter()
                        // 线程池大小，最多有多少个线程同时并发
                        .withCoreSize(2)
                        // 排队，默认为 -1 ，假设 10 个请求，2 个执行，2 个排队，那么其他 6 个将直接返回错误
                        .withMaxQueueSize(2)
                )

        );
        this.productId = productId;
    }

    @Override
    protected ProductInfo run() throws Exception {
        String url = "http://localhost:7000/getProduct?productId=" + productId;
        String response = HttpClientUtils.sendGetRequest(url);
        System.out.println("睡眠 5 秒，模拟");
        TimeUnit.SECONDS.sleep(5);
        return JSON.parseObject(response, ProductInfo.class);
    }
}

 
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@RequestMapping("/getProduct")
public ProductInfo getProduct(Long productId) {
    GetProductCommand getProductCommand = new GetProductCommand(productId);
    // 同步执行
    ProductInfo productInfo = getProductCommand.execute();
    return productInfo;
}
 
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package cn.mrcode.cachepdp.eshop.cache.ha.hystrix.command;

import com.alibaba.fastjson.JSON;
import com.netflix.hystrix.HystrixCommandGroupKey;
import com.netflix.hystrix.HystrixObservableCommand;

import cn.mrcode.cachepdp.eshop.cache.ha.http.HttpClientUtils;
import cn.mrcode.cachepdp.eshop.cache.ha.model.ProductInfo;
import rx.Observable;
import rx.schedulers.Schedulers;

/**
 * ${todo}
 *
 * @author : zhuqiang
 * @date : 2019/6/2 15:41
 */
public class GetProductsCommand extends HystrixObservableCommand {
    private Long[] pids;

    public GetProductsCommand(Long[] pids) {
        super(HystrixCommandGroupKey.Factory.asKey("GetProductCommandGroup"));
        this.pids = pids;
    }

    @Override
    protected Observable construct() {
        // create OnSubscribe 方法已经过时
        // 文档说改为了 unsafeCreate 方法
        return Observable.unsafeCreate((Observable.OnSubscribe<ProductInfo>) onSubscribe -> {
//            for (Long pid : pids) {
//                String url = "http://localhost:7000/getProduct?productId=" + pid;
//                String response = HttpClientUtils.sendGetRequest(url);
//                onSubscribe.onNext(JSON.parseObject(response, ProductInfo.class));
//            }
//            onSubscribe.onCompleted();
            try {
                if (!onSubscribe.isUnsubscribed()) {
                    for (Long pid : pids) {
                        String url = "http://localhost:7000/getProduct?productId=" + pid;
                        String response = HttpClientUtils.sendGetRequest(url);
                        onSubscribe.onNext(JSON.parseObject(response, ProductInfo.class));
                    }
                    onSubscribe.onCompleted();
                }
            } catch (Exception e) {
                onSubscribe.onError(e);
            }
        }).subscribeOn(Schedulers.io());
    }
}

 
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/**
 * @param productIds 英文逗号分隔
 */
@RequestMapping("/getProducts")
public void getProduct(String productIds) {
    List<Long> pids = Arrays.stream(productIds.split(",")).map(Long::parseLong).collect(Collectors.toList());
    GetProductsCommand getProductsCommand = new GetProductsCommand(pids.toArray(new Long[pids.size()]));
    // 第一种获取数据模式
    getProductsCommand.observe().subscribe(productInfo -> {
        System.out.println(productInfo);
    });
    System.out.println("方法已执行完成");
}
 
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// 第二种获取数据模式
// 注意不要多次在同一个 command 上订阅
// 否则报错 GetProductsCommand command executed multiple times - this is not permitted.
getProductsCommand.observe().subscribe(new Observer<ProductInfo>() {

    @Override
    public void onCompleted() {
        System.out.println("Observer: onCompleted");
    }

    @Override
    public void onError(Throwable e) {
        System.out.println("Observer: onError:" + e);
    }

    @Override
    public void onNext(ProductInfo productInfo) {
        System.out.println("Observer: onNext:" + productInfo);
    }
});
 
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// 同步调用方式
Iterator<ProductInfo> iterator = getProductsCommand.observe().toBlocking().getIterator();
while (iterator.hasNext()) {
    System.out.println(iterator.next());
}
 
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