1. 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。
位于 Spring-core 包中 util 包下。
2. PathMatcher 接口源码
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);
}
3. AntPathMatcher
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。我们平时使用的路径匹配基本用的都是这个。
1. 通配符
?表示匹配任意一个字符
System.out.println( matcher.match("/usr/name?", "/usr/name1") ); //true
System.out.println( matcher.match("/usr/name?", "/usr/name111") ); //false
*表示匹配单个路径
System.out.println( matcher.match("/usr/*", "/usr/list")); //true
System.out.println( matcher.match("/usr/*", "/usr/list/again")); //false
System.out.println( matcher.match("/usr/*.app", "/usr/list.app")); //true
System.out.println( matcher.match("/usr/*.app", "/usr/list.html")); //false
**表示匹配多级路径
System.out.println( matcher.match("/usr/**", "/usr/list") ); //true
System.out.println( matcher.match("/usr/**", "/usr/list/again") ); //true
- 通过 extractPathWithinPattern() 方法匹配
/**
* extractPathWithinPattern 返回符合匹配的部分路径，去除路径开头静态部分
**/
System.out.println( matcher.extractPathWithinPattern("/usr/*", "/usr/list") ); //list
System.out.println( matcher.extractPathWithinPattern("/usr/*/again", "/usr/list/again/age") ); // list/again/age
System.out.println( matcher.extractPathWithinPattern("/usr/*.html", "/usr/list") ); //list
System.out.println( matcher.extractPathWithinPattern("/usr/*.html", "/usr/list.html") ); //list.html
2. 变量绑定
变量绑定可以让我们在匹配过程中提取路径中的参数，并将其赋值给指定的变量。
System.out.println( matcher.extractUriTemplateVariables("/usr/{name}/{age}", "/usr/张三/12") ); //{name=张三, age=12}