获取Spring中@PathVariable注解里带点的完整参数

背景

spring-boot的版本是2.1.4.RELEASE，spring的版本是5.1.6.RELEASE

一个例子如下：

@Configuration @Import(WebMvcAutoConfiguration.EnableWebMvcConfiguration.class) @SuppressWarnings("unchecked") public class WebConfig implements WebMvcConfigurer, WebMvcRegistrations {     @Override     public RequestMappingHandlerMapping getRequestMappingHandlerMapping() {         return new RequestMappingHandlerMapping();     } }  @RestController public class ParamController {     @GetMapping(value = "/param/{param1}")     public String param(@PathVariable("param1") String param1) {         return param1;     } }  @SpringBootApplication public class MyApplication {     public static void main(String[] args) {         SpringApplication.run(MyApplication.class, args);     } } 

启动一下，访问http://127.0.0.1:8080/param/hehe和http://127.0.0.1:8080/param/hehe.hehe都返回hehe

如果访问http://127.0.0.1:8080/param/hehe.hehe.hehe，它会返回hehe.hehe

所以会发现它把最后一个小数点后面的字符给截掉了，那如果我们想要获取完整的字符串，该怎么办呢？

探索

1. 参数怎么来的

入口在InvocableHandlerMethod.invokeForRequest，如下：

是根据PathVariableMethodArgumentResolver.resolveName得来的，如下：

HandlerMapping.URI_TEMPLATE_VARIABLES_ATTRIBUTE = HandlerMapping.class.getName() + ".uriTemplateVariables";

什么时候放进attributes里的？，在RequestMappingInfoHandlerMapping.handleMatch，如下：

2. 参数怎么解析的

程序定义的：/param/{param1} -> /param/{param1}.* 接口传过来的：/param/hehe.hehe  以/分割，第一个字符串param里没有参数，所以会跳过，直接看第二个字符串： {param1}.* -> pattern=(.*)/Q./E.* hehe.hehe  param1=hehe 

我们定义的是/param/{param1}，怎么就变成了/param/{param1}.*？在PatternsRequestCondition.getMatchingPattern

可以看到如果useSuffixPatternMatch为true，并且指定的url里没有.，会在后缀自动增加.*

3. useSuffixPatternMatch是在哪里设置的？

public class RequestMappingHandlerMapping extends RequestMappingInfoHandlerMapping   implements MatchableHandlerMapping, EmbeddedValueResolverAware {   private boolean useSuffixPatternMatch = true;   @Override  public void afterPropertiesSet() {   this.config = new RequestMappingInfo.BuilderConfiguration();   this.config.setUrlPathHelper(getUrlPathHelper());   this.config.setPathMatcher(getPathMatcher());   this.config.setSuffixPatternMatch(this.useSuffixPatternMatch); // 这里设置了   this.config.setTrailingSlashMatch(this.useTrailingSlashMatch);   this.config.setRegisteredSuffixPatternMatch(this.useRegisteredSuffixPatternMatch);   this.config.setContentNegotiationManager(getContentNegotiationManager());    super.afterPropertiesSet();  } } 

解决

1. 修改WebConfig的getRequestMappingHandlerMapping

@Configuration @Import(WebMvcAutoConfiguration.EnableWebMvcConfiguration.class) @SuppressWarnings("unchecked") public class WebConfig implements WebMvcConfigurer, WebMvcRegistrations {     @Override     public RequestMappingHandlerMapping getRequestMappingHandlerMapping() {         RequestMappingHandlerMapping requestMappingHandlerMapping = new RequestMappingHandlerMapping();         requestMappingHandlerMapping.setUseSuffixPatternMatch(false);         return requestMappingHandlerMapping;     } } 

2. 增加configurePathMatch方法

@Configuration @Import(WebMvcAutoConfiguration.EnableWebMvcConfiguration.class) @SuppressWarnings("unchecked") public class WebConfig implements WebMvcConfigurer, WebMvcRegistrations {     @Override     public RequestMappingHandlerMapping getRequestMappingHandlerMapping() {         return new RequestMappingHandlerMapping();     }      @Override     public void configurePathMatch(PathMatchConfigurer configurer) {         configurer.setUseSuffixPatternMatch(false);     } } 

3. url中增加点

a. 中间的参数是不受影响的

@RestController public class ParamController {     @GetMapping(value = "/param/{param1}/{param2}")     public String param(@PathVariable("param1") String param1, @PathVariable("param2") String param2) {         return param1 + " " + param2;     } } 

访问http://127.0.0.1:8080/param/hehe.hehe/hehe.hee返回hehe.hehe hehe

b. 增加点

@RestController public class ParamController {     //@GetMapping(value = "/param/{param1}")     //public String param(@PathVariable("param1") String param1) {     //    return param1;     //}      @GetMapping(value = "/param/{param1}.{param2}")     public String param(@PathVariable("param1") String param1, @PathVariable("param2") String param2) {         return param1 + " " + param2;     } } 

访问http://127.0.0.1:8080/param/hehe.hehe返回hehe hehe

注意第一个方法和第二个方法不要同时出现，如果同时出现的话，则会访问第一个方法

@RestController public class ParamController {     @GetMapping(value = "/param/{param1}")     public String param(@PathVariable("param1") String param1) {         return param1;     }      @GetMapping(value = "/param/{param1}.{param2}")     public String param(@PathVariable("param1") String param1, @PathVariable("param2") String param2) {         return param1 + " " + param2;     } } 

访问http://127.0.0.1:8080/param/hehe.heh返回hehe

4. 修改参数

@RestController public class ParamController {     @GetMapping(value = "/param/{param1:.+}")     public String param(@PathVariable("param1") String param1) {         return param1;     } } 

访问http://127.0.0.1:8080/param/hehe.hehe，返回hehe.hehe

原因如下：

/param/{param1:.+} -> /param/{param1:.+} /param/hehe.hehe  {param1:.+} -> pattern=(.+) hehe.hehe  param1=hehe.hehe 

得到pattern以及提取参数的类 AntPathStringMatcher  protected static class AntPathStringMatcher {    private static final Pattern GLOB_PATTERN = Pattern.compile("//?|//*|//{((?://{[^/]+?//}|[^/{}]|////[{}])+?)//}");    private static final String DEFAULT_VARIABLE_PATTERN = "(.*)";    private final Pattern pattern;    private final List<String> variableNames = new LinkedList<>();    public AntPathStringMatcher(String pattern) {    this(pattern, true);   }    public AntPathStringMatcher(String pattern, boolean caseSensitive) {    StringBuilder patternBuilder = new StringBuilder();    Matcher matcher = GLOB_PATTERN.matcher(pattern);    int end = 0;    while (matcher.find()) {     patternBuilder.append(quote(pattern, end, matcher.start()));     String match = matcher.group();     if ("?".equals(match)) {      patternBuilder.append('.');     }     else if ("*".equals(match)) {      patternBuilder.append(".*");     }     else if (match.startsWith("{") && match.endsWith("}")) {      int colonIdx = match.indexOf(':');      if (colonIdx == -1) {       patternBuilder.append(DEFAULT_VARIABLE_PATTERN);       this.variableNames.add(matcher.group(1));      }      else {       String variablePattern = match.substring(colonIdx + 1, match.length() - 1);       patternBuilder.append('(');       patternBuilder.append(variablePattern);       patternBuilder.append(')');       String variableName = match.substring(1, colonIdx);       this.variableNames.add(variableName);      }     }     end = matcher.end();    }    patternBuilder.append(quote(pattern, end, pattern.length()));    this.pattern = (caseSensitive ? Pattern.compile(patternBuilder.toString()) :      Pattern.compile(patternBuilder.toString(), Pattern.CASE_INSENSITIVE));   }    private String quote(String s, int start, int end) {    if (start == end) {     return "";    }    return Pattern.quote(s.substring(start, end));   }    /**    * Main entry point.    * @return {@code true} if the string matches against the pattern, or {@code false} otherwise.    */   public boolean matchStrings(String str, @Nullable Map<String, String> uriTemplateVariables) {    Matcher matcher = this.pattern.matcher(str);    if (matcher.matches()) {     if (uriTemplateVariables != null) {      // SPR-8455      if (this.variableNames.size() != matcher.groupCount()) {       throw new IllegalArgumentException("The number of capturing groups in the pattern segment " +         this.pattern + " does not match the number of URI template variables it defines, " +         "which can occur if capturing groups are used in a URI template regex. " +         "Use non-capturing groups instead.");      }      for (int i = 1; i <= matcher.groupCount(); i++) {       String name = this.variableNames.get(i - 1);       String value = matcher.group(i);       uriTemplateVariables.put(name, value);      }     }     return true;    }    else {     return false;    }   }  }