教程:一塊兒學習Hystrix--Hystrix命令名稱、分組、線程池

時間 2019-11-09

標籤教程一塊兒學習 hystrix 命令名稱分組線程简体版

原文原文鏈接

Hystrix本系列

如下爲博主寫Hystrix系列的文章列表html

點擊查看 Hystrix入門java

點擊查看 Hystrix命令執行git

點擊查看 Hystrix處理異常機制(降級方法)github

命令名稱

默認狀況下，命令名稱來源於類名。後端

getClass().getSimpleName();

若是要顯示定義名稱的話，能夠經過 HystrixCommand 或者 HystrixObservableCommand 的構造函數：緩存

public HystrixHelloWorldCommand(String name) {
        super(Setter.withGroupKey(HystrixCommandGroupKey.Factory.asKey("Command Group: Hello World"))
                .andCommandKey(HystrixCommandKey.Factory.asKey("Command Name: Hello World")));
        this.name = name;
    }

爲了給每一個命令集合保存Setter配置，能夠緩存Setter，示例以下：ide

private static final Setter cachedSetter =
            Setter.withGroupKey(HystrixCommandGroupKey.Factory.asKey("ExampleGroup"))
                    .andCommandKey(HystrixCommandKey.Factory.asKey("Cache Setter: Hello World"));
    public HystrixHelloWorldCommand(String name) {
        super(cachedSetter);
        this.name = name;
    }

HystrixCommandKey 是一個接口，能夠做爲枚舉或者普通類實現。其實它有一個輔助工廠類，示例以下：函數

HystrixCommandKey.Factory.asKey("Command Name: Hello World")

HystrixCommandKey 源碼以下：單元測試

public interface HystrixCommandKey extends HystrixKey {
    public static class Factory {
private static final InternMap<String, HystrixCommandKey.Factory.HystrixCommandKeyDefault> intern = new InternMap(new ValueConstructor<String, HystrixCommandKey.Factory.HystrixCommandKeyDefault>() {
            public HystrixCommandKey.Factory.HystrixCommandKeyDefault create(String key) {
                return new HystrixCommandKey.Factory.HystrixCommandKeyDefault(key);
            }
        });

        private Factory() {
        }

        public static HystrixCommandKey asKey(String name) {
            return (HystrixCommandKey)intern.interned(name);
        }

        static int getCommandCount() {
            return intern.size();
        }

        private static class HystrixCommandKeyDefault extends HystrixKeyDefault implements HystrixCommandKey {
            public HystrixCommandKeyDefault(String name) {
                super(name);
            }
        }
    }
}

點擊查看源碼和單元測試測試

命令分組

Hystrix使用命令分組將一塊兒的命令進行管理，好比報告、警報、儀表盤或組/庫。默認狀況下，Hystrix使用 HystrixCommandGroupKey 來定義命令線程池，除非單獨定義線程池。

HystrixCommandGroupKey 是一個接口，能夠做爲枚舉或者普通類實現。其實它有一個輔助工廠類，示例以下：

HystrixCommandGroupKey.Factory.asKey("Command Group: Hello World")

HystrixCommandGroupKey 源碼以下：

public interface HystrixCommandGroupKey extends HystrixKey {
    public static class Factory {
        private static final InternMap<String, HystrixCommandGroupKey.Factory.HystrixCommandGroupDefault> intern = new InternMap(new ValueConstructor<String, HystrixCommandGroupKey.Factory.HystrixCommandGroupDefault>() {
            public HystrixCommandGroupKey.Factory.HystrixCommandGroupDefault create(String key) {
                return new HystrixCommandGroupKey.Factory.HystrixCommandGroupDefault(key);
            }
        });

        private Factory() {
        }

        public static HystrixCommandGroupKey asKey(String name) {
            return (HystrixCommandGroupKey)intern.interned(name);
        }

        static int getGroupCount() {
            return intern.size();
        }

        private static class HystrixCommandGroupDefault extends HystrixKeyDefault implements HystrixCommandGroupKey {
            public HystrixCommandGroupDefault(String name) {
                super(name);
            }
        }
    }
}

點擊查看源碼和單元測試

命令線程池

線程池主要體現是用於監測、指標發佈、緩存和其餘此類用途的HystrixThreadPool。一個HystrixCommand與一個單獨注入到它的HystrixThreadPoolKey所檢索到的HystrixThreadPool相關聯，或者默認爲使用HystrixCommandGroupKey的建立一個。

若是要顯示定義名稱的話，能夠經過 HystrixCommand 或者 HystrixObservableCommand 的構造函數：

public HystrixHelloWorldCommand(String name) {
        super(Setter.withGroupKey(HystrixCommandGroupKey.Factory.asKey("Command Group: Hello World"))
                .andCommandKey(HystrixCommandKey.Factory.asKey("Command Name: Hello World"))
                .andThreadPoolKey(HystrixThreadPoolKey.Factory.asKey("Command ThreadPool: Hello World")));
        this.name = name;
    }

HystrixThreadPoolKey 是一個接口，能夠做爲枚舉或者普通類實現。其實它有一個輔助工廠類，示例以下：

HystrixThreadPoolKey.Factory.asKey("Command ThreadPool: Hello World")

HystrixThreadPoolKey 源碼以下：

public interface HystrixThreadPoolKey extends HystrixKey {
    class Factory {
        private Factory() {
        }
        private static final InternMap<String, HystrixThreadPoolKey> intern
                = new InternMap<String, HystrixThreadPoolKey>(
                new InternMap.ValueConstructor<String, HystrixThreadPoolKey>() {
                    @Override
                    public HystrixThreadPoolKey create(String key) {
                        return new HystrixThreadPoolKeyDefault(key);
                    }
                });
     
        public static HystrixThreadPoolKey asKey(String name) {
           return intern.interned(name);
        }

        private static class HystrixThreadPoolKeyDefault extends HystrixKeyDefault implements HystrixThreadPoolKey {
            public HystrixThreadPoolKeyDefault(String name) {
                super(name);
            }
        }

        static int getThreadPoolCount() {
            return intern.size();
        }
    }
}

可能使用HystrixThreadPoolKey而不單單是不一樣的HystrixCommandGroupKey的緣由是多個命令可能屬於相同的全部權或邏輯功能的「組」，可是某些命令可能須要彼此隔離。

簡單示例以下: