import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.TimeUnit;
import java.util.stream.IntStream;public class Test {public static void main(String[] args){ThreadLocalExample.test();}
}/*21.2 線程上下文設(shè)計(jì)*/class ApplicationConfiguration {}
class RuntimeInfo {}
class ActionContext {}final class ApplicationContext{private ApplicationConfiguration configuration;private RuntimeInfo runtimeInfo;//。。。private static class Holder{private static ApplicationContext instance = new ApplicationContext();}public static ApplicationContext getContext() {return Holder.instance;}public ApplicationConfiguration getConfiguration() {return configuration;}public void setConfiguration(ApplicationConfiguration configuration) {this.configuration = configuration;}public RuntimeInfo getRuntimeInfo() {return runtimeInfo;}public void setRuntimeInfo(RuntimeInfo runtimeInfo) {this.runtimeInfo = runtimeInfo;}/*需求：單個(gè)線程執(zhí)行的步驟會(huì)非常多，后一個(gè)步驟的輸入可能是前一個(gè)步驟的輸出，比如單個(gè)線程多步驟執(zhí)行時(shí)，為了使得功能單一，有時(shí)候我們會(huì)采用職責(zé)鏈設(shè)計(jì)模式。雖然有時(shí)候后一個(gè)步驟未必需要前一個(gè)步驟的輸出結(jié)果，但是都需要將context從頭到尾進(jìn)行傳遞，假如方法參數(shù)比較少還可以容忍，如果方法參數(shù)比較多，在七八次的調(diào)用甚至十幾次的調(diào)用，都需要從頭到尾地傳遞context，很顯然這是一種比較繁瑣的設(shè)計(jì)，我們可以采用上下文設(shè)計(jì)來解決這樣的問題。*/private ConcurrentHashMap<Thread,ActionContext> contexts =new ConcurrentHashMap<>();public ActionContext getContexts() {ActionContext actionContext = contexts.get(Thread.currentThread());if(actionContext==null){actionContext=new ActionContext();contexts.put(Thread.currentThread(),actionContext);}return actionContext;}
}/*21.3.2 ThreadLocal的方法詳解及源碼分析*/
class ThreadLocalExample{public static void test() {ThreadLocal<Integer> l = new ThreadLocal<>();IntStream.range(0, 10).forEach(i->new Thread(()->{try{l.set(i);System.out.println(Thread.currentThread()+ " set i "+l.get());TimeUnit.SECONDS.sleep(1);System.out.println(Thread.currentThread()+ " set i "+l.get());} catch (InterruptedException e) {e.printStackTrace();}}).start());try {TimeUnit.SECONDS.sleep(3);System.out.println(l.get());} catch (InterruptedException e) {e.printStackTrace();}}
}

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《Java高并發(fā)編程詳解》筆記

轉(zhuǎn)載于:https://www.cnblogs.com/junjie2019/p/10607204.html

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