ThreadLocal学习

public class ThreadLocalExample {

    private static final ThreadLocal<String> threadLocalVariable = new ThreadLocal<>();

    public static void main(String[] args) {
        // 创建并启动两个线程
        Thread thread1 = new Thread(() -> {
            // 在线程1中设置 ThreadLocal 变量的值
            threadLocalVariable.set("Value from Thread 1");
            printThreadLocalVariable();
        });

        Thread thread2 = new Thread(() -> {
            // 在线程2中设置 ThreadLocal 变量的值
            threadLocalVariable.set("Value from Thread 2");
            printThreadLocalVariable();
        });

        thread1.start();
        thread2.start();
    }

    // 打印 ThreadLocal 变量的值
    private static void printThreadLocalVariable() {
        // 获取当前线程的 ThreadLocal 变量的值
        String value = threadLocalVariable.get();
        System.out.println("Thread: " + Thread.currentThread().getName() + ", ThreadLocal Variable Value: " + value);
        // 清理 ThreadLocal 变量，确保不影响其他线程
        threadLocalVariable.remove();
    }
}

public void set(T value) {
    Thread t = Thread.currentThread();
    ThreadLocalMap map = getMap(t);
    if (map != null)
        map.set(this, value);
    else
        createMap(t, value);
}

ThreadLocalMap getMap(Thread t) {
    return t.threadLocals;
}

public T get() {
    Thread t = Thread.currentThread();
    ThreadLocalMap map = getMap(t);
    if (map != null) {
        ThreadLocalMap.Entry e = map.getEntry(this);
        if (e != null) {
            @SuppressWarnings("unchecked")
            T result = (T)e.value;
            return result;
        }
    }
    return setInitialValue();
}

@Slf4j
public class UserUtil {

    private static final ThreadLocal<UserInfo> threadLocal = new TransmittableThreadLocal<>();


    public static UserInfo getUser() {
        return threadLocal.get();
    }

    public static void setUser(UserInfo adminUser) {
        threadLocal.set(adminUser);
    }

    public static void removeUser() {
        threadLocal.remove();
    }

}

@Around("(execution(* com.lxw.*.controller..*(..))")
public Object around(ProceedingJoinPoint point) throws Throwable {
    try {
        ServletRequestAttributes attributes = ((ServletRequestAttributes) RequestContextHolder.getRequestAttributes());
        HttpServletRequest request = attributes.getRequest();
        String token = request.getHeader(Const.TOKEN_NAME);
        if (StrUtil.isNotEmpty(token)) {
            UserInfo userInfo = redis.get(token);
            UserUtil.setUser(userInfo);
        }
        return point.proceed();
    } finally {
        UserUtil.removeUser();
    }
}

package org.springframework.web.context.request;
public abstract class RequestContextHolder {
    private static final ThreadLocal<RequestAttributes> requestAttributesHolder = new NamedThreadLocal("Request attributes");
    private static final ThreadLocal<RequestAttributes> inheritableRequestAttributesHolder = new NamedInheritableThreadLocal("Request context");
    
    public static RequestAttributes getRequestAttributes() {
        RequestAttributes attributes = (RequestAttributes)requestAttributesHolder.get();
        if (attributes == null) {
            attributes = (RequestAttributes)inheritableRequestAttributesHolder.get();
        }

        return attributes;
    }
    
}