如何保留多线程所需的公共数据

Question

I have a multi threaded environment. Within those threads I need to make some http call. This is an existing code. Now the new requirement is that I need to pass a token to those call. So I need to keep this token to some where and need to get it during the call.

So my question is what will be the best implementation to keep the token.

I can store the token in some singleton class and get the value from there. What will be the merit / demerit of this approach.

Thanx in advance.

Answer 1

Wherever you store it, you need to store it in thread safe memory. For example, you could declare the variable used to store it volatile .

For ease of access, you could use a singleton, but a static variable in a convenient class might be easier.

Answer 2

If I understand your problem correctly, you want to generate some token from parent thread then you can use in child threads in during Http request.

The below approach can be used. You can use the InheritableThreadLocal variable to store the token and then it can be used safely by the child threads.

public class ThreadContext {
    private static ThreadLocal<String> currentThread = new InheritableThreadLocal<>();

    public static String getCurrentThread() {
        return currentThread.get();
    }

    public static void setCurrentThread(String tenant) {
        currentThread.set(tenant);
    }

    public static void clear() {
        currentThread.set(null);
    }
}

You can set the token using the ThreadContext.setCurrentThread(String tenant) method. And in the child thread, you can use ThreadContext.getCurrentThread();