SpringMVC的路徑匹配規則是依照Ant的來的.
實際上不只是SpringMVC,整個Spring框架的路徑解析都是按照Ant的風格來的.
在Spring中的具體實現,詳情參見 org.springframework.util.AntPathMatcher.
具體規則如下(來自Spring AntPathMatcher源碼注釋):
* {@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.
換成人話就是:
?匹配1個字符*匹配0個或多個字符**匹配路徑中的0個或多個目錄{spring:[a-z]+}將正則表達式[a-z]+匹配到的值,賦值給名為spring的路徑變量.(PS:必須是完全匹配才行,在SpringMVC中只有完全匹配才會進入controller層的方法)
一個一個的分析.
符號 ?
和其它幾個不一樣的是,? 要求必須為一個字符,並且不能是代表路徑分隔符的/.
@RequestMapping("/index?")
@ResponseBody
public String index(){
System.out.println("11");
return "11";
}
結果:
index false 404錯誤(必須要有一個字符)
index/ false 404錯誤(不能為"/")
indexab false 404錯誤(不能是多個字符)
indexa true 輸出 11
符號 *
*,雖然可以匹配多個任意的字符,但是,如果你以為 * 可以替代 ** 那就錯了,* 代表的多個任意字符組成的字符串不能是個 目錄 或者說 路徑.也就是說,* 並不能拿來替代 **.
示例代碼:
@RequestMapping("/index*")
@ResponseBody
public String index(){
System.out.println("11");
return "11";
}
結果:
index true 輸出 11(可以為0字符)
index/ true 輸出 11(可以為"/")
indexa true 輸出 11(可以為1個字符)
indexabc true 輸出 11(可以為多個字符)
index/a false 404錯誤("/a"是一個路徑)
符號 **
0個或多個目錄.** 代表的字符串本身不一定要包含 /
@RequestMapping("/index/**/a")
@ResponseBody
public String index(){
System.out.println();
return "11";
}
結果:
index/a true 輸出 11(可以為0個目錄)
index/x/a true 輸出 11(可以為一個目錄)
index/x/z/c/a true 輸出 11(可以為多個目錄)
符號 {spring:[a-z]+}
其它的關於 AntPathMatcher 的文章里,對 {spring:[a-z]+} 的匹配大多是只字未提.這里補充下.
示例代碼:
@RequestMapping("/index/{username:[a-b]+}")
@ResponseBody
public String index(@PathVariable("username") String username){
System.out.println(username);
return username;
}
結果:
index/ab true 輸出 ab
index/abbaaa true 輸出 abbaaa
index/a false 404錯誤
index/ac false 404錯誤
附錄(完整測試用例)
節選自 AntPathMatcherTests.不得不說 Spring 的測試用例寫的實在是太完善了.
// 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 **'s
assertTrue(pathMatcher.match("/**", "/testing/testing"));
assertTrue(pathMatcher.match("/*/**", "/testing/testing"));
assertTrue(pathMatcher.match("/**/*", "/testing/testing"));
assertTrue(pathMatcher.match("/bla/**/bla", "/bla/testing/testing/bla"));
assertTrue(pathMatcher.match("/bla/**/bla", "/bla/testing/testing/bla/bla"));
assertTrue(pathMatcher.match("/**/test", "/bla/bla/test"));
assertTrue(pathMatcher.match("/bla/**/**/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*/**/bla/**", "/XXXblaXXXX/testing/testing/bla/testing/testing/"));
assertTrue(pathMatcher.match("/*bla*/**/bla/*", "/XXXblaXXXX/testing/testing/bla/testing"));
assertTrue(pathMatcher.match("/*bla*/**/bla/**", "/XXXblaXXXX/testing/testing/bla/testing/testing"));
assertTrue(pathMatcher.match("/*bla*/**/bla/**", "/XXXblaXXXX/testing/testing/bla/testing/testing.jpg"));
assertTrue(pathMatcher.match("*bla*/**/bla/**", "XXXblaXXXX/testing/testing/bla/testing/testing/"));
assertTrue(pathMatcher.match("*bla*/**/bla/*", "XXXblaXXXX/testing/testing/bla/testing"));
assertTrue(pathMatcher.match("*bla*/**/bla/**", "XXXblaXXXX/testing/testing/bla/testing/testing"));
assertFalse(pathMatcher.match("*bla*/**/bla/*", "XXXblaXXXX/testing/testing/bla/testing/testing"));
assertFalse(pathMatcher.match("/x/x/**/bla", "/x/x/x/"));
assertTrue(pathMatcher.match("/foo/bar/**", "/foo/bar")) ;
assertTrue(pathMatcher.match("", ""));
assertTrue(pathMatcher.match("/{bla}.*", "/testing.html"));