🍓2. TTL缓存用户数据

1. ThreadLocal 使用场景

1.1. 用户会话信息

public class UserContext {
    private static ThreadLocal userHolder = ThreadLocal.withInitial(() -> null);

    public static void setUser(String user) {
        userHolder.set(user);
    }

    public static String getUser() {
        return userHolder.get();
    }

    public static void clear() {
        userHolder.remove();
    }
}

// 在某个请求处理线程中使用
UserContext.setUser("UserA");
String currentUser = UserContext.getUser();
System.out.println("Current User: " + currentUser);
UserContext.clear();

1.2. 格式化工具

public class DateFormatter {
    private static ThreadLocal dateFormatHolder = ThreadLocal.withInitial(() -> new SimpleDateFormat("yyyy-MM-dd"));

    public static String format(Date date) {
        return dateFormatHolder.get().format(date);
    }
}

// 在某个线程中使用
String formattedDate = DateFormatter.format(new Date());
System.out.println("Formatted Date: " + formattedDate);

1.3. 上下文日志信息传递

public class LogContext {
    private static ThreadLocal requestIdHolder = ThreadLocal.withInitial(() -> null);

    public static void setRequestId(String requestId) {
        requestIdHolder.set(requestId);
    }

    public static String getRequestId() {
        return requestIdHolder.get();
    }

    public static void clear() {
        requestIdHolder.remove();
    }
}

// 在某个请求处理线程中使用
LogContext.setRequestId("123456");
String requestId = LogContext.getRequestId();
System.out.println("Request ID: " + requestId);
LogContext.clear();

2. Transmitt...