基于Spring概念模型:PathMatcher 路径匹配器

源代码版本 : spring-webmvc-5.1.4.RELEASE

概述

PathMatcher是Spring的一个概念模型接口，该接口抽象建模了概念"路径匹配器"，一个"路径匹配器"是一个用于路径匹配的工具。它的使用者是 :

org.springframework.core.io.support.PathMatchingResourcePatternResolver
org.springframework.web.servlet.handler.AbstractUrlHandlerMapping
org.springframework.web.servlet.mvc.WebContentInterceptor

Spring框架自身对概念模型接口也提供了一个缺省的实现AntPathMatcher,用于匹配Ant风格的路径。

PathMatcher接口源代码

PathMatcher接口源代码如下 :

package org.springframework.util;
import java.util.Comparator;
import java.util.Map;
public interface PathMatcher {
/**
* Does the given path represent a pattern that can be matched
* by an implementation of this interface?
* 判断指定的路径 path 是否是一个 pattern(模式)
* 如果返回值是 false，也就是说 path 不是一个模式，而是一个静态路径(真正的路径字符串),
* 那么就不用调用方法 #match 了，因为对于静态路径的匹配，直接使用字符串等号比较就足够了。
* @param path the path String to check
* @return true if the given path represents a pattern
*/
boolean isPattern(String path);
/**
* Match the given path against the given pattern,
* according to this PathMatcher's matching strategy.
* 根据当前 PathMatcher 的匹配策略，检查指定的径 path 和指定的模式 pattern 是否匹配
* @param 用于检测路径字符串是否匹配于某个模式时所用的模式
* @param path 需要被检测的路径字符串
* @return true 表示匹配， false 表示不匹配
*/
boolean match(String pattern, String path);
/**
* Match the given  path against the corresponding part of the given
* pattern, according to this PathMatcher's matching strategy.
* 根据当前 PathMatcher 的匹配策略，检查指定的径 path 和指定的模式 pattern 是否之间
* 是否为前缀匹配
* @param pattern the pattern to match against
* @param path the path String to test
* @return true 表示匹配， false 表示不匹配
*/
boolean matchStart(String pattern, String path);
/**
* Given a pattern and a full path, determine the pattern-mapped part.
* 给定一个模式 pattern 和一个全路径 path，判断路径中和模式匹配的部分。
    *
* This method is supposed to find out which part of the path is matched
* dynamically through an actual pattern, that is, it strips off a statically
* defined leading path from the given full path, returning only the actually
* pattern-matched part of the path.
* 该方法用于发现路径中的哪一部分是和模式能动态匹配上的部分。它会去除路径中开头静态部分，
* 仅仅返回那部分真正和模式匹配的上的部分。
* 例子 : "myroot/*.html" 为 pattern , "myroot/myfile.html" 为路径，
*  则该方法返回 "myfile.html".  
* 具体的检测规则根据当前 PathMatcher 的匹配策略来顶。
* A simple implementation may return the given full path as-is in case
* of an actual pattern, and the empty String in case of the pattern not
* containing any dynamic parts (i.e. the pattern parameter being
* a static path that wouldn't qualify as an actual #isPattern pattern.
* A sophisticated implementation will differentiate between the static parts
* and the dynamic parts of the given path pattern.
* @param pattern the path pattern
* @param path the full path to introspect
* @return the pattern-mapped part of the given path
* (never null)
*/
String extractPathWithinPattern(String pattern, String path);
/**
* Given a pattern and a full path, extract the URI template variables. URI template
* variables are expressed through curly brackets ('{' and '}').
* 给定一个模式和一个路径，提取其中的 URI 模板变量信息。URI模板变量表达式格式为 "{variable}"
*      
* 例子 : pattern  为 "/hotels/{hotel}" ，路径为 "/hotels/1", 则该方法会返回一个 map ，
    * 内容为 : "hotel"->"1".
* @param pattern the path pattern, possibly containing URI templates
* @param path the full path to extract template variables from
* @return a map, containing variable names as keys; variables values as values
*/
Map<String, String> extractUriTemplateVariables(String pattern, String path);
/**
* Given a full path, returns a Comparator suitable for sorting patterns
* in order of explicitness for that path.
* The full algorithm used depends on the underlying implementation,
* but generally, the returned Comparator will sort a list so that more
    * specific patterns come before generic patterns.
* @param path the full path to use for comparison
* @return a comparator capable of sorting patterns in order of explicitness
*/
Comparator<String> getPatternComparator(String path);
/**
* Combines two patterns into a new pattern that is returned.
* The full algorithm used for combining the two pattern depends on the underlying implementation.
* 合并两个模式。具体合并的算法由实现类决定。
* @param pattern1 the first pattern
* @param pattern2 the second pattern
* @return the combination of the two patterns
* @throws IllegalArgumentException when the two patterns cannot be combined
*/
String combine(String pattern1, String pattern2);
}

从接口代码来理解概念还是有些抽象，下面我们列举一些基于实现类AntPathMatcher的例子来增强理解 。

AntPathMatcher使用例子

AntPathMatcher antPathMatcher = new AntPathMatcher();
antPathMatcher.isPattern("/user/001");// 返回 false
antPathMatcher.isPattern("/user/*"); // 返回 true
antPathMatcher.match("/user/001","/user/001");// 返回 true
antPathMatcher.match("/user/*","/user/001");// 返回 true
antPathMatcher.matchStart("/user/*","/user/001"); // 返回 true
antPathMatcher.matchStart("/user/*","/user"); // 返回 true
antPathMatcher.matchStart("/user/*","/user001"); // 返回 false
antPathMatcher.extractPathWithinPattern("uc/profile*","uc/profile.html"); // 返回 profile.html
antPathMatcher.combine("uc/*.html","uc/profile.html"); // uc/profile.html

spring的路径匹配工具 AntPathMatcher

包路径：

org.springframework.util.AntPathMatcher

工具：

AntPathMatcher antPathMatcher = new AntPathMatcher();

以下代码为本人使用过的路径匹配工具代码

方便以后项目中使用参考：

//不需要鉴权的接口
   private Boolean excludePathFilter(String path) {
       PathProperties pathProperties = (PathProperties) PathProperties.applicationContext.getBean("pathProperties");
       List<String> excludePathPatterns = pathProperties.getExcludePathPatterns();
       if(CollectionUtils.isEmpty(excludePathPatterns)){
           return false;
       }
       return excludePathPatterns.stream().anyMatch(pattern -> antPathMatcher.match(pattern, path));
   }

核心代码是这一行

excludePathPatterns.stream().anyMatch(pattern -> antPathMatcher.match(pattern, path))

获取到需要排除鉴权接口列表的接口，然后通过 AntPathMatcher 的 match 方法去匹配路径，不需要做鉴权的接口就会被匹配到，然后继续执行非鉴权的业务流程。

来源：https://andyboke.blog.csdn.net/article/details/88884286