Question

在我的Spring Boot（2.1.4）应用程序中，我需要使用拦截器的RequestEntity方法访问preHandle。不幸的是，我似乎无法获得它的实例。

我的代码基本上是这样的：

@RestController
@RequestMapping("/")
public class MyController
{
    @GetMapping("/")
    @ResponseBody
    public ResponseEntity getSomething()
    // public ResponseEntity getSomething(RequestEntity<String> requestEntity) // doesn't work either
    {
        return new ResponseEntity<String>("test", HttpStatus.OK);
    }
}

和这样的拦截器：

public class MyInterceptor extends HandlerInterceptorAdapter
{
    // doesn't work:
    // @Autowired RequestEntity<String> requestEntity;

    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception exception) throws Exception {}

    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {}

    @Override
    public boolean preHandle(HttpServletRequest requestServlet, HttpServletResponse responseServlet, Object handler) throws Exception
    {

        // ACCESS TO org.springframework.http.RequestEntity NEEDED HERE!

        // NULL POINTER EXCEPTION!
        requestEntity.getHeaders();

        return true;
    }
}

无论是否将RequestEntity注入Controller，我似乎都无法访问（传入）请求的RequestEntity。我试图将其@Autowire插入拦截器，但无济于事。

有什么方法可以访问它？

Answer 1

您可以在preHandle方法中使请求实体执行类似的操作

 HttpEntity requestEntity = ((HttpEntityEnclosingRequest) request).getEntity();

希望这对您有帮助

Answer 2

如果要拦截preHandle中的标头，而不是requestEntity.getHeaders()，可以使用：

requestServlet.getHeaderNames();

此方法具有：

/**
 * Returns an enumeration of all the header names this request contains. If
 * the request has no headers, this method returns an empty enumeration.
 * <p>
 * Some servlet containers do not allow servlets to access headers using
 * this method, in which case this method returns <code>null</code>
 *
 * @return an enumeration of all the header names sent with this request; if
 *         the request has no headers, an empty enumeration; if the servlet
 *         container does not allow servlets to use this method,
 *         <code>null</code>
 */
public Enumeration<String> getHeaderNames();

您将拥有请愿书的所有标题名称。使用每个标题名称，您可以访问每个标题的值：

requestServlet.getHeader(headerName);

此方法可以访问：

/**
 * Returns the value of the specified request header as a
 * <code>String</code>. If the request did not include a header of the
 * specified name, this method returns <code>null</code>. If there are
 * multiple headers with the same name, this method returns the first head
 * in the request. The header name is case insensitive. You can use this
 * method with any request header.
 *
 * @param name
 *            a <code>String</code> specifying the header name
 * @return a <code>String</code> containing the value of the requested
 *         header, or <code>null</code> if the request does not have a
 *         header of that name
 */
public String getHeader(String name);

在拦截器中访问Spring的RequestEntity

2 个答案: