Spring过滤器：获取servlet url模式

Question

假设我已经定义了这些RESTendpoint：

@RequestMapping(path = "/user")
@RestController
public class ConfigUserController {

    [...]
    
    @GetMapping(path = "/variables/")
    public ResponseEntity<List<Variable>> getAllVariables(...)
        [...]
    }
    
    @GetMapping(path = "/variables/{name}")
    public ResponseEntity<Variable> getVariableByName(...)
        [...]
    }
    
    @PutMapping(path = "/variables/{name}/{value}")
    public ResponseEntity<Variable> setVariableByName(...)
        [...]
    }
}

我定义了两个过滤器（日志记录和授权），在这些过滤器中，我想获得与当前请求匹配的url模式。使用上述示例：

• 如果请求是一个GET到 /variables，我需要"/变量"
• 如果请求是一个GET到 /variables/myfancyname，我需要"/变量/{name}"
• 如果请求是一个PUT到 /variables/myfancyname/myvalue，我需要"/变量/{名称}/{值}"

基本上，我需要的是在我的过滤器的doFilter（ServletRequest-request-request，ServletResponse-response，FilterChain-chain）方法中获得映射注释中定义的路径。

理想情况下，我希望能够访问我的过滤器中的url模式值，如下所示：

@Component
@Order(3)
public class MyAuthorizationRequestFilter extends GenericFilterBean {
    [...]
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
        // here I get the value
        String urlPattern = request.useSomeMethod().toGetUrlPattern();
        [...]
        boolean auth = false;
        // here I do stuff
        [...]
        // finally let's see if the user is authorized
        if (auth) {
            chain.doFilter(request, responde);
        } else {
            throw SomeAuthorizationError();
        }
    }
    [...]
}

我一直在寻找，但我找不到一个可行的解决方案。

如果可能的话，我宁愿不扫描集合或web.xml文件（我没有），也不使用反射，因为每次触发过滤器时都会执行代码，我不想影响性能。

欢迎链接或建议。

编辑：添加详细信息，添加过滤器示例cose

Answer 1

过滤器在请求到达DispatcherServlet之前拦截请求，使其成为粗粒度任务的理想选择，例如：

• 身份验证

注意*在尝试调用getAttribute之前，先执行doFilter

您的控制器

@RequestMapping(path = "/user")
@RestController
public class ConfigUserController {

    @GetMapping(path = "/variables/")
    public ResponseEntity<List<Variable>> getAllVariables() {
        return null;
    }

    @GetMapping(path = "/variables/{name}")
    public ResponseEntity<Variable> getVariableByName(@PathVariable("name") String name) {
        return new ResponseEntity<Variable>(new Variable(name), HttpStatus.OK);
    }

    @PutMapping(path = "/variables/{name}/{value}")
    public ResponseEntity<Variable> setVariableByName() {
        return null;
    }
}

定制过滤器

@Component
@Order(Ordered.HIGHEST_PRECEDENCE)
public class CustomFilter implements Filter {

    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
            throws IOException, ServletException {
        // TODO
        try {
            chain.doFilter(request, response);
        } catch (Exception e) {
        } finally {
            String pattern = (String) request.getAttribute(HandlerMapping.BEST_MATCHING_PATTERN_ATTRIBUTE);
            System.out.println("Request template is, " + pattern);
        }
    }

}

订单号：

 Request template is, /user/variables/{name}

HandlerIntercepors拦截DispatcherServlet和我们的控制器之间的请求。这是在Spring MVC框架内完成的，它提供了对处理程序和ModelAndView对象的访问。

自定义拦截器

@Component
public class LoggerInterceptor implements HandlerInterceptor {

    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object object, Exception arg3)
            throws Exception {

    }

    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object object, ModelAndView model)
            throws Exception {

    }

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object object) throws Exception {
        String path = (String) request.getAttribute(HandlerMapping.BEST_MATCHING_PATTERN_ATTRIBUTE);
        System.out.println("path : " + path);
        return true;
    }}

向InterceptorRegistry注册

@Component
public class CustomServiceInterceptorAppConfig implements WebMvcConfigurer {
   @Autowired
   LoggerInterceptor loggerInterceptor;

   @Override
   public void addInterceptors(InterceptorRegistry registry) {
      registry.addInterceptor(loggerInterceptor);
   }
}

单例作用域并设置为预实例化（默认）的Bean是在创建容器时创建的。这是一个一次性过程，您不必担心性能。

您可以预扫描所有@RequestMapping、@GetMapping、@PostMApping等。。注释，保留它，然后在过滤器中匹配模式以获得所需的结果。

这是样品

豆

@Configuration
public class Config {

    @Bean
    public List<String> getPatterns() throws ClassNotFoundException {

        List<String> str = new ArrayList<String>();
        Class clazz = Class.forName("com.example.demo.controller.ConfigUserController"); // or list of controllers,
                                                                                            // //you can iterate that
                                                                                            // list
        for (Method method : clazz.getMethods()) {
            for (Annotation annotation : method.getDeclaredAnnotations()) {
                if (annotation.toString().contains("GetMapping")) {
                    str.add(annotation.toString());
                    System.out.println("Annotation is..." + annotation.toString());
                }
                if (annotation.toString().contains("PutMapping")) {
                    str.add(annotation.toString());
                    System.out.println("Annotation is..." + annotation.toString());
                }
                if (annotation.toString().contains("PostMapping")) {
                    str.add(annotation.toString());
                    System.out.println("Annotation is..." + annotation.toString());
                }
            }
        }

        return str;

    }

定制过滤器

@Component
@Order(Ordered.HIGHEST_PRECEDENCE)
public class CustomFilter implements Filter {
    @Autowired
    Config con;
    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
            throws IOException, ServletException {
        // TODO
        try {
            //filter match the pattern to get the desired result
            System.out.println(con.getPatterns());
        } catch (ClassNotFoundException e) {
            
        }
        chain.doFilter(request, response);
    }

Answer 2

更新答案以使用GenericFilterBean。根据提出的问题进行筛选。可以通过添加finally子句来实现这一点。这是必需的，因为您需要执行链。doFilter（请求，响应）首先调用请求。getAttribute，因为该属性直到请求生命周期的后期才设置。因此，如果您试图基于传入的uri模板执行某些操作，那么在这里子类化GenericFilterBean可能不是正确的选择，因为您需要调用chain。先进行doFilter。

 public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
        try {
            //Do something
            chain.doFilter(request, response);
        } finally {
         String pathTemplate = (String) 
request.getAttribute(HandlerMapping.BEST_MATCHING_PATTERN_ATTRIBUTE);
         System.out.println("Incoming Request path Template from Generic Filter : " + pathTemplate);
}


}

替代选项：

假设您在这里使用的是Spring Web。您可以定义一个HandlerInterceptor并将其注册到Interceptor注册表。

@Component
public class LogPathTemplateInterceptor
        implements HandlerInterceptor {
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object object) throws Exception {
        String pathTemplate = (String)request.getAttribute(HandlerMapping.BEST_MATCHING_PATTERN_ATTRIBUTE);
        System.out.println("Incoming Request path Template : " + pathTemplate);
        return true;
    }
}

定义完后，向InterceptorRegistry注册它。查看如何将路径模式添加到拦截器。

@Configuration
public class InterceptorConfig implements WebMvcConfigurer {
    @Autowired
    private LogPathTemplateInterceptor logInterceptor;
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(logInterceptor)
                .addPathPatterns("/variables/**");
    }
}

这应该记录请求模板路径，而不是带有变量的路径。