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#yyds干货盘点#【Spring专题】「技术原理」为大家介绍一下Spring中的Ant路径匹配工具...

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#yyds干货盘点#【Spring专题】「技术原理」为大家介绍一下Spring中的Ant路径匹配工具组件AntPathMatcher

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浩宇天尚 2022-01-11 12:40:33 博主文章分类：Spring技术专题系列 ©著作权

文章标签 spring html 404错误 文章分类 Java 编程语言 阅读数432

Spring中的绝大多数的路径匹配规则是依照Ant的标准来的

实际上不只是SpringMVC，整个Spring框架的路径解析都是按照Ant的风格来的，在Spring中的具体实现,详情参见 org.springframework.util.AntPathMatcher，具体规则如下

/**
* {@link PathMatcher} implementation for Ant-style path patterns.
*
* <p>Part of this mapping code has been kindly borrowed from <a href="http://ant.apache.org">Apache Ant</a>.
*
* <p>The mapping matches URLs using the following rules:<br>
* <ul>
* <li>{@code ?} matches one character</li>
* <li>{@code *} matches zero or more characters</li>
* <li>{@code **} matches zero or more <em>directories</em> in a path</li>
* <li>{@code {spring:[a-z]+}} matches the regexp {@code [a-z]+} as a path variable named "spring"</li>
* </ul>
*
* <h3>Examples</h3>
* <ul>
* <li>{@code com/t?st.jsp} — matches {@code com/test.jsp} but also
* {@code com/tast.jsp} or {@code com/txst.jsp}</li>
* <li>{@code com/*.jsp} — matches all {@code .jsp} files in the
* {@code com} directory</li>
* <li><code>com/**/test.jsp</code> — matches all {@code test.jsp}
* files underneath the {@code com} path</li>
* <li><code>org/springframework/**/*.jsp</code> — matches all
* {@code .jsp} files underneath the {@code org/springframework} path</li>
* <li><code>org/**/servlet/bla.jsp</code> — matches
* {@code org/springframework/servlet/bla.jsp} but also
* {@code org/springframework/testing/servlet/bla.jsp} and {@code org/servlet/bla.jsp}</li>
* <li>{@code com/{filename:\\w+}.jsp} will match {@code com/test.jsp} and assign the value {@code test}
* to the {@code filename} variable</li>
* </ul>
*
* <p><strong>Note:</strong> a pattern and a path must both be absolute or must
* both be relative in order for the two to match. Therefore it is recommended
* that users of this implementation to sanitize patterns in order to prefix
* them with "/" as it makes sense in the context in which they're used.
* /

符号的规则定义标准

  • ? 匹配1个字符
  • * 匹配0个或多个字符
  • ** 匹配路径中的0个或多个目录
  • {spring:[a-z]+} 将正则表达式[a-z]+匹配到的值，赋值给名为spring的路径变量。

必须是完全匹配才行，在SpringMVC中只有完全匹配才会进入controller层的方法

和其它几个不一样的是? 要求必须为一个字符，并且不能是代表路径分隔符的/。

@RequestMapping("/index?")
@ResponseBody
public String index(){
return "index.html";
}
index false 404错误(必须要有一个字符)
index/ false 404错误(不能为"/")
indexab false 404错误(不能是多个字符)
indexa true 输出页面index.html
`
  • ，虽然可以匹配多个任意的字符，但是，无法用 * 可以替代 ** ，因为 * 代表的多个任意字符组成的字符串不能是个目录或者说路径.也就是说，* 并不能拿来替代 **.
示例代码:
@RequestMapping("/index*")
@ResponseBody
public String index(){
return "index.html";
}
index true 输出index.html(可以为0字符)
index/ true 输出 index.html(可以为"/")
indexa true 输出 index.html(可以为1个字符)
indexabc true 输出 index.html(可以为多个字符)
index/a false 404错误("/a"是一个路径)
`

0个或多个目录.** 代表的字符串本身不一定要包含 /

@RequestMapping("/index/**/a")
@ResponseBody
public String index(){
return "index.html";
}
index/a true 输出 index.html(可以为0个目录)
index/x/a true 输出 index.html(可以为一个目录)
index/x/z/c/a true 输出 index.html(可以为多个目录)
`

符号 {spring:[a-z]+}

其它的关于 AntPathMatcher 的文章里,对 {spring:[a-z]+} 的匹配大多是只字未提.这里补充下.示例代码:

@RequestMapping("/index/{username:[a-b]+}") @ResponseBody public String index(@PathVariable("username") String username){ System.out.println(username); return username; }

结果:

index/ab true 输出 ab index/abbaaa true 输出 abbaaa index/a false 404错误 index/ac false 404错误

需求：我在做rbac权限校验的时候，设置管理员的访问路径为/admin/**,希望所有的开头为/admin/的uri操作地址都能进行匹配判断。

手动使用方式
  • AntPathMatcher不仅可以匹配Spring的@RequestMapping路径，也可以用来匹配各种字符串，包括文件路径等。
  • AntPathMatcher默认路径分隔符为“/”，而在匹配文件路径时，需要注意Windows下路径分隔符为“\”，Linux下为“/”，写法即为：
初始化创建操作

匹配文件路径，使用AntPathMatcher创建一个对象时，需要注意AntPathMatcher也有有参构造，传递路径分隔符参数pathSeparator，对于文件路径的匹配来说，则需要根据不同的操作系统来传递各自的文件分隔符，以此防止匹配文件路径错误。

AntPathMatcher matcher = new AntPathMatcher(File.separator)；
AntPathMatcher matcher = new AntPathMatcher(System.getProperty("file.separator"))；
执行匹配操作
import org.springframework.util.AntPathMatcher;
String content = "/admin/acuff";
String pattern = "/admin/**";
System.out.println(antPathMatcher.match(pattern, content));
最长匹配原则(has more characters)

最长匹配规则（has more characters），即越精确的模式越会被优先匹配到。例如，URL请求/app/dir/file.jsp，现在存在两个路径匹配模式/**/*.jsp和/app/dir/*.jsp，那么会根据模式/app/dir/*.jsp来匹配。当然如果觉得这个工具还不够强大，还可以使用RegexRequestMatcher ，它支持使用正则表达式对URL地址进行匹配。如果你觉得这些都不够强大可以自己重写 RequestMatcher接口来进行定制的路由匹配规则

摘取网上的案例参考Sample

// test exact matching
assertTrue(pathMatcher.match("test", "test"));
assertTrue(pathMatcher.match("/test", "/test"));
assertTrue(pathMatcher.match("http://example.org", "http://example.org")); // SPR-14141
assertFalse(pathMatcher.match("/test.jpg", "test.jpg"));
assertFalse(pathMatcher.match("test", "/test"));
assertFalse(pathMatcher.match("/test", "test"));

// test matching with ?'s
assertTrue(pathMatcher.match("t?st", "test"));
assertTrue(pathMatcher.match("??st", "test"));
assertTrue(pathMatcher.match("tes?", "test"));
assertTrue(pathMatcher.match("te??", "test"));
assertTrue(pathMatcher.match("?es?", "test"));
assertFalse(pathMatcher.match("tes?", "tes"));
assertFalse(pathMatcher.match("tes?", "testt"));
assertFalse(pathMatcher.match("tes?", "tsst"));

// test matching with *'s
assertTrue(pathMatcher.match("*", "test"));
assertTrue(pathMatcher.match("test*", "test"));
assertTrue(pathMatcher.match("test*", "testTest"));
assertTrue(pathMatcher.match("test/*", "test/Test"));
assertTrue(pathMatcher.match("test/*", "test/t"));
assertTrue(pathMatcher.match("test/*", "test/"));
assertTrue(pathMatcher.match("*test*", "AnothertestTest"));
assertTrue(pathMatcher.match("*test", "Anothertest"));
assertTrue(pathMatcher.match("*.*", "test."));
assertTrue(pathMatcher.match("*.*", "test.test"));
assertTrue(pathMatcher.match("*.*", "test.test.test"));
assertTrue(pathMatcher.match("test*aaa", "testblaaaa"));
assertFalse(pathMatcher.match("test*", "tst"));
assertFalse(pathMatcher.match("test*", "tsttest"));
assertFalse(pathMatcher.match("test*", "test/"));
assertFalse(pathMatcher.match("test*", "test/t"));
assertFalse(pathMatcher.match("test/*", "test"));
assertFalse(pathMatcher.match("*test*", "tsttst"));
assertFalse(pathMatcher.match("*test", "tsttst"));
assertFalse(pathMatcher.match("*.*", "tsttst"));
assertFalse(pathMatcher.match("test*aaa", "test"));
assertFalse(pathMatcher.match("test*aaa", "testblaaab"));

// test matching with ?'s and /'s
assertTrue(pathMatcher.match("/?", "/a"));
assertTrue(pathMatcher.match("/?/a", "/a/a"));
assertTrue(pathMatcher.match("/a/?", "/a/b"));
assertTrue(pathMatcher.match("/??/a", "/aa/a"));
assertTrue(pathMatcher.match("/a/??", "/a/bb"));
assertTrue(pathMatcher.match("/?", "/a"));

// test matching with <strong>'s
assertTrue(pathMatcher.match("/</strong>", "/testing/testing"));
assertTrue(pathMatcher.match("/*/<strong>", "/testing/testing"));
assertTrue(pathMatcher.match("/</strong>/*", "/testing/testing"));
assertTrue(pathMatcher.match("/bla/<strong>/bla", "/bla/testing/testing/bla"));
assertTrue(pathMatcher.match("/bla/</strong>/bla", "/bla/testing/testing/bla/bla"));
assertTrue(pathMatcher.match("/<strong>/test", "/bla/bla/test"));
assertTrue(pathMatcher.match("/bla/</strong>/**/bla", "/bla/bla/bla/bla/bla/bla"));
assertTrue(pathMatcher.match("/bla*bla/test", "/blaXXXbla/test"));
assertTrue(pathMatcher.match("/*bla/test", "/XXXbla/test"));
assertFalse(pathMatcher.match("/bla*bla/test", "/blaXXXbl/test"));
assertFalse(pathMatcher.match("/*bla/test", "XXXblab/test"));
assertFalse(pathMatcher.match("/*bla/test", "XXXbl/test"));

assertFalse(pathMatcher.match("/????", "/bala/bla"));
assertFalse(pathMatcher.match("/**/*bla", "/bla/bla/bla/bbb"));

assertTrue(pathMatcher.match("/*bla*/<strong>/bla/</strong>", "/XXXblaXXXX/testing/testing/bla/testing/testing/"));
assertTrue(pathMatcher.match("/*bla*/**/bla/*", "/XXXblaXXXX/testing/testing/bla/testing"));
assertTrue(pathMatcher.match("/*bla*/<strong>/bla/</strong>", "/XXXblaXXXX/testing/testing/bla/testing/testing"));
assertTrue(pathMatcher.match("/*bla*/<strong>/bla/</strong>", "/XXXblaXXXX/testing/testing/bla/testing/testing.jpg"));

assertTrue(pathMatcher.match("*bla*/<strong>/bla/</strong>", "XXXblaXXXX/testing/testing/bla/testing/testing/"));
assertTrue(pathMatcher.match("*bla*/**/bla/*", "XXXblaXXXX/testing/testing/bla/testing"));
assertTrue(pathMatcher.match("*bla*/<strong>/bla/</strong>", "XXXblaXXXX/testing/testing/bla/testing/testing"));
assertFalse(pathMatcher.match("*bla*/**/bla/*", "XXXblaXXXX/testing/testing/bla/testing/testing"));

assertFalse(pathMatcher.match("/x/x/<strong>/bla", "/x/x/x/"));

assertTrue(pathMatcher.match("/foo/bar/</strong>", "/foo/bar")) ;

assertTrue(pathMatcher.match("", ""));

assertTrue(pathMatcher.match("/{bla}.*", "/testing.html"));
`

spring mvc url地址匹配工具类

AntPathRequestMatcher

在spring mvc 中我们会经常使用//*.jsp、/app//dir/file.、/**/example 、/app/*.x 类似于这样语法而负责真正判断是否匹配的工具类就是AntPathRequestMatcher

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