Spring 在应用过滤器时区分带和不带尾部斜线的路径

Question

我正在开发一个 Spring 引导应用程序，我想在某些特定的 URL 中应用一些过滤器，为此我正在实现 Filter 接口（下面的代码）并使用 FilterRegistrationBean 其中我有方法 setUrlPatterns 来定义使用过滤器的端点。我从头开始创建了一个示例应用程序，并为 /hello 设置了过滤器，但过滤器不适用于 /hello/.

这使得有必要将行从 filterRegistrationBean.setUrlPatterns(List.of("/hello")); 到 filterRegistrationBean.setUrlPatterns(List.of("/hello", "/hello/"));。它解决了我的问题，但我不想复制仅包含尾部斜杠的路径。

有没有更好的方法来代替 List.of("/hello", "/hello/")?

代码：

import javax.servlet.*;
import java.io.IOException;

public class LogFilter implements Filter {

    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
        System.out.println("-----------------FILTER-----------------");
        chain.doFilter(request, response);
    }

    // ... other methods
}

import com.example.demo.config.filters.LogFilter;
import org.springframework.boot.web.servlet.FilterRegistrationBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

import java.util.List;

@Configuration
public class WebConfig {

    @Bean
    public FilterRegistrationBean<LogFilter> logFilter() {
        var filterRegistrationBean = new FilterRegistrationBean<>(new LogFilter());
        filterRegistrationBean.setUrlPatterns(List.of("/hello"));
        return filterRegistrationBean;
    }
}

import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController()
@RequestMapping("/hello")
public class HelloController {

    @GetMapping
    public String hello() {
        return "Hello";
    }
}

研究：

还有一种定义过滤器的方法，启用@ServletComponentScan，创建一个实现Filter的class并用@WebFilter(urlPatterns = {"/hello"})注释，但结果是一样的.
我可以使用 /hello/*，它会考虑带和不带尾部斜杠的路径，但我不想对 /hello/abc/ 等其他所有内容应用过滤器，我想应用仅针对 /hello（和 /hello/）进行过滤。

我在嵌入式 Tomcat 上进行了调试，我发现 ApplicationFilterFactory 它使用一些逻辑来决定何时在路径中应用过滤器，它看起来重复路径是唯一的解决方案，但在这个例子中我只使用一个路径，假设你有 20..30 个路径用于这个过滤器，一旦复制以包含尾部斜线它就变成 40..60，所以我试图为此找到另一个解决方案（由于嵌入式 tomcat).

上的 ApplicationFilterFactory 实现，我不确定是否有其他解决方案

Answer 1

See here :

setUrlPatterns

public void setUrlPatterns(Collection<String> urlPatterns)

Set the URL patterns that the filter will be registered against. This will replace any previously specified URL patterns. ...

此方法的变体（具有更精确的文档）：

addUrlPatterns

public void addUrlPatterns(String... urlPatterns)

Add URL patterns, as defined in the Servlet specification, that the filter will be registered against.

...（搜索；）：

=> Servlet Spec
- =>（最新）3.1.final:

12.2 Specification of Mappings

In the Web application deployment descriptor, the following syntax is used to define mappings:

A string beginning with a / character and ending with a /* suffix is used for path mapping.

A string beginning with a *. prefix is used as an extension mapping.

The empty string ("") is a special URL pattern that exactly maps to the application's context root, i.e., requests of the form http://host:port/<contextroot>/. In this case the path info is / and the servlet path and context path is empty string ("").

A string containing only the / character indicates the "default" servlet of the application. In this case the servlet path is the request URI minus the context path and the path info is null.

All other strings are used for exact matches only.

If the effective web.xml (after merging information from fragments and annotations) contains any url-patterns that are mapped to multiple servlets then the deployment must fail.

所以对于你的核心问题：

Is there a better way to do this instead write List.of("/hello", "/hello/")?

不（抱歉），Servlet <=3.1 不支持。根据此规范，"hello", "hello/" 将是两个完全匹配。（并且 List.of(few, ..., items) 是“非常酷”/最新的/不可变的！；））

Spring 在应用过滤器时区分带和不带尾部斜线的路径

Spring differentiates path with and without trailing slash when applying filters

java

spring

spring-boot

tomcat

filter

12.2 Specification of Mappings