Java 如何使用方面将自定义标头添加到 HttpServletRequest

我try 创建一个方面来覆盖 HttpServletRequest个 参数，然后才实际执行控制器处理程序方法.但事实证明，HttpServletRequest始终是RequestFacade实例，即使我在方面方法中将其替换为Custom HttpServletRequestWrapper.

以下是代码:

// the annotation:

@Target({ElementType.METHOD})
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface MyAnnotation {
}

// the aspect:
@Component
@Aspect
@Slf4j
public class MyAspect {
    @Pointcut("@annotation(com.example.springtest.annotation.MyAnnotation)")
    public void pointcut() {
    }

    @Around("pointcut()")
    public Object setHeader(ProceedingJoinPoint pjp) throws Throwable {
        var args = pjp.getArgs();
        var signature = (MethodSignature) pjp.getSignature();
        var method = signature.getMethod();
        var annotations = method.getDeclaredAnnotations();
        var need = Arrays.stream(annotations).anyMatch(a -> a.annotationType().equals(MyAnnotation.class));
        if (!need) {
            return pjp.proceed();
        }

        for (var i = 0; i < args.length; i++) {
            var arg = args[i];
            if (arg instanceof HttpServletRequest request) {
                args[i] = new HttpServletRequestWrapper(request) {
                    @Override
                    public String getHeader(String name) {
                        if (name.equalsIgnoreCase("my-header")) {
                            return "my-header";
                        } else {
                            return super.getHeader(name);
                        }
                    }
                };
            }
        }
        return pjp.proceed();
    }

}

// the bootstrap class:
@Configurable
@EnableAspectJAutoProxy
@SpringBootApplication
public class SpringtestApplication {

    public static void main(String[] args) {
        SpringApplication.run(SpringtestApplication.class, args);
    }

}

// and the controller
@RestController
public class TestController {

    private static final Logger log = LoggerFactory.getLogger(TestController.class);

    @MyAnnotation
    @GetMapping("/get-my-header")
    public String getMyHeader(HttpServletRequest request) {
        if (Objects.requireNonNull(request) instanceof HttpServletRequestWrapper) {
            log.info("is wrapper");
        } else {
            log.info("request:{}", request.getClass());
        }
        return request.getHeader("my-header");
    }
}

那么，那里发生了什么呢？在我替换了HttpServletRequest参数之后，是否有其他代理类实例更改了它？

日志(log)显示方面和控制器中的请求参数都是RequestFacade实例.

我还try 创建一个服务方法，并将我的定制HttpServletRequestWrapper实例直接发送给它.这一次，该参数没有更改.