springboot 在集成 swagger2 启动时遇到如下错误：
java.lang.IllegalArgumentException: No enum constant org.springframework.web.bind.annotation.RequestMethod.post
at java.lang.Enum.valueOf(Enum.java:238) ~[na:1.8.0_261]
at org.springframework.web.bind.annotation.RequestMethod.valueOf(RequestMethod.java:35) ~[spring-web-5.1.3.RELEASE.jar:5.1.3.RELEASE]
at springfox.documentation.swagger.readers.operation.OperationHttpMethodReader.apply(OperationHttpMethodReader.java:49) ~[springfox-swagger-common-2.6.1.jar:2.6.1]
at springfox.documentation.spring.web.plugins.DocumentationPluginsManager.operation(DocumentationPluginsManager.java:123) [springfox-spring-web-2.6.1.jar:2.6.1]
at springfox.documentation.spring.web.readers.operation.ApiOperationReader.read(ApiOperationReader.java:73) [springfox-spring-web-2.6.1.jar:2.6.1]
at springfox.documentation.spring.web.scanners.CachingOperationReader$1.load(CachingOperationReader.java:50) [springfox-spring-web-2.6.1.jar:2.6.1]
at springfox.documentation.spring.web.scanners.CachingOperationReader$1.load(CachingOperationReader.java:48) [springfox-spring-web-2.6.1.jar:2.6.1]
at com.google.common.cache.LocalCache$LoadingValueReference.loadFuture(LocalCache.java:3527) [guava-18.0.jar:na]
at com.google.common.cache.LocalCache$Segment.loadSync(LocalCache.java:2319) [guava-18.0.jar:na]
at com.google.common.cache.LocalCache$Segment.lockedGetOrLoad(LocalCache.java:2282) [guava-18.0.jar:na]
at com.google.common.cache.LocalCache$Segment.get(LocalCache.java:2197) [guava-18.0.jar:na]
at com.google.common.cache.LocalCache.get(LocalCache.java:3937) [guava-18.0.jar:na]
at com.google.common.cache.LocalCache.getOrLoad(LocalCache.java:3941) [guava-18.0.jar:na]
at com.google.common.cache.LocalCache$LocalLoadingCache.get(LocalCache.java:4824) [guava-18.0.jar:na]
at com.google.common.cache.LocalCache$LocalLoadingCache.getUnchecked(LocalCache.java:4830) [guava-18.0.jar:na]
at springfox.documentation.spring.web.scanners.CachingOperationReader.read(CachingOperationReader.java:57) [springfox-spring-web-2.6.1.jar:2.6.1]
at springfox.documentation.spring.web.scanners.ApiDescriptionReader.read(ApiDescriptionReader.java:66) [springfox-spring-web-2.6.1.jar:2.6.1]
at springfox.documentation.spring.web.scanners.ApiListingScanner.scan(ApiListingScanner.java:89) [springfox-spring-web-2.6.1.jar:2.6.1]
at springfox.documentation.spring.web.scanners.ApiDocumentationScanner.scan(ApiDocumentationScanner.java:70) [springfox-spring-web-2.6.1.jar:2.6.1]
at springfox.documentation.spring.web.plugins.DocumentationPluginsBootstrapper.scanDocumentation(DocumentationPluginsBootstrapper.java:85) [springfox-spring-web-2.6.1.jar:2.6.1]
at springfox.documentation.spring.web.plugins.DocumentationPluginsBootstrapper.start(DocumentationPluginsBootstrapper.java:127) [springfox-spring-web-2.6.1.jar:2.6.1]
at org.springframework.context.support.DefaultLifecycleProcessor.doStart(DefaultLifecycleProcessor.java:182) [spring-context-5.1.3.RELEASE.jar:5.1.3.RELEASE]
at org.springframework.context.support.DefaultLifecycleProcessor.access$200(DefaultLifecycleProcessor.java:53) [spring-context-5.1.3.RELEASE.jar:5.1.3.RELEASE]
at org.springframework.context.support.DefaultLifecycleProcessor$LifecycleGroup.start(DefaultLifecycleProcessor.java:360) [spring-context-5.1.3.RELEASE.jar:5.1.3.RELEASE]
at org.springframework.context.support.DefaultLifecycleProcessor.startBeans(DefaultLifecycleProcessor.java:158) [spring-context-5.1.3.RELEASE.jar:5.1.3.RELEASE]
at org.springframework.context.support.DefaultLifecycleProcessor.onRefresh(DefaultLifecycleProcessor.java:122) [spring-context-5.1.3.RELEASE.jar:5.1.3.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.finishRefresh(AbstractApplicationContext.java:879) [spring-context-5.1.3.RELEASE.jar:5.1.3.RELEASE]
at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.finishRefresh(ServletWebServerApplicationContext.java:163) [spring-boot-2.1.1.RELEASE.jar:2.1.1.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:549) [spring-context-5.1.3.RELEASE.jar:5.1.3.RELEASE]
at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:142) [spring-boot-2.1.1.RELEASE.jar:2.1.1.RELEASE]
at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:775) [spring-boot-2.1.1.RELEASE.jar:2.1.1.RELEASE]
at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:397) [spring-boot-2.1.1.RELEASE.jar:2.1.1.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:316) [spring-boot-2.1.1.RELEASE.jar:2.1.1.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1260) [spring-boot-2.1.1.RELEASE.jar:2.1.1.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1248) [spring-boot-2.1.1.RELEASE.jar:2.1.1.RELEASE]
at com.zuolh.lab.Application.main(Application.java:19) [classes/:na]
在 controller 中用的是注解@RequestMapping,在集成 swagger2 之前可以正常访问， 那问题就一定处在 swagger2 相关的 code 中， 于是检查在 code 中哪里用到了 httpMethod, 发现了问题所在：
public enum RequestMethod {
GET,
HEAD,
POST,
PUT,
PATCH,
DELETE,
OPTIONS,
TRACE;
private RequestMethod() {
}枚举类中 method 方法都是大写， 而我的代码中将 httpmethod 写成了：
@ApiOperation(value = "登录成功后获取cookies信息", httpMethod = "post")所以只需要将 httpMethod=”post”改为 httpMethod = “POST”就好了
