线程上下文

//设计为单例
public final class ActionContext {

    // 构造方法私有化
    private ActionContext() {

    }

    // Holder类
    private static class ContextHolder {
        private final static ActionContext actionContext = new ActionContext();

    }

    // 提供给外部使用
    public static ActionContext getActionContext() {
        return ContextHolder.actionContext;
    }

    // 属性
    public Context getContext() {
        return threadLocal.get();
    }

    // 属性
    private final ThreadLocal<Context> threadLocal = new ThreadLocal<Context>() {
        @Override
        protected Context initialValue() {
            return new Context();
        }
    };

}


public class Context {

    private String name;
    private String cardId;

    public String getCardId() {
        return cardId;
    }

    public void setCardId(String cardId) {
        this.cardId = cardId;
    }

    public String getName() {
        return this.name;
    }

    public void setName(String name) {
        this.name = name;
    }
}


public class ExecutionTask implements Runnable {

    private QueryFromDBAction queryAction = new QueryFromDBAction();

    private QueryFromHttpAction httpAction = new QueryFromHttpAction();

    @Override
    public void run() {

        queryAction.execute();
        System.out.println("The name query successful");
        httpAction.execute();
        System.out.println("The cardId query successful");

        Context context = ActionContext.getActionContext().getContext();
        System.out.println("The Name is " + context.getName() + " and CardId  is " + context.getCardId());
    }
}

public class QueryFromDBAction {

    public void execute() {

        try {
            Thread.sleep(1000L);
            String name = Thread.currentThread().getName() +"中的Jack";
            ActionContext.getActionContext().getContext().setName(name);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }
}

public class QueryFromHttpAction {

    public void execute() {
        Context context = ActionContext.getActionContext().getContext();
        String name = context.getName();
        String cardId = getCardId(name);
        context.setCardId(cardId);


    }

    private String getCardId(String name) {
        try {
            Thread.sleep(1000L);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        return Thread.currentThread().getName()+"中的cardId";
    }
}

public class ContextTest {

    public static void main(String[] args) {

        IntStream.rangeClosed(1, 4)
                .forEach(i ->
                        new Thread(new ExecutionTask(),"【线程"+i+"】").start()
                );
    }
}