RequestContextHolder 是线程安全的吗

RequestContextHolder 是 Spring 框架中的一个类，它提供了一种在当前线程中存储请求上下文信息的机制。对于每个发送到服务器的请求，Spring 将会为其创建一个新的线程来处理。在多线程环境中，同时存在多个请求，每个请求都需要有自己的上下文信息，而 RequestContextHolder 就是用来解决这个问题的。

java
import org.springframework.web.context.request.RequestContextHolder;
import org.springframework.web.context.request.ServletRequestAttributes;
public class ExampleController {
    public void exampleMethod() {
        // 获取当前线程的请求上下文
        ServletRequestAttributes attributes = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes();
        
        // 获取请求的信息
        HttpServletRequest request = attributes.getRequest();
        String url = request.getRequestURL().toString();
        
        // 打印请求的 URL
        System.out.println("请求的 URL：" + url);
    }
}

java
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.web.context.request.RequestContextHolder;
import org.springframework.web.context.request.ServletRequestAttributes;
public class ExampleController {
    private static final Logger logger = LoggerFactory.getLogger(ExampleController.class);
    public void exampleMethod() {
        ServletRequestAttributes attributes = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes();
        
        HttpServletRequest request = attributes.getRequest();
        String url = request.getRequestURL().toString();
        String params = request.getQueryString();
        
        logger.info("请求的 URL：{}，请求的参数：{}", url, params);
    }
}

java
import org.springframework.security.core.Authentication;
import org.springframework.security.core.context.SecurityContextHolder;
import org.springframework.web.context.request.RequestContextHolder;
import org.springframework.web.context.request.ServletRequestAttributes;
public class ExampleController {
    public void exampleMethod() {
        ServletRequestAttributes attributes = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes();
        
        HttpServletRequest request = attributes.getRequest();
        String ip = request.getRemoteAddr();
        
        // 获取当前用户的认证信息
        Authentication authentication = SecurityContextHolder.getContext().getAuthentication();
        String username = authentication.getName();
        
        // 权限验证逻辑
        // ...
    }
}