Swagger2异常:java.lang.NumberFormatException: For input string: ““

java.lang.NumberFormatException: For input string: ""
  at java.lang.NumberFormatException.forInputString(NumberFormatException.java:65)
  at java.lang.Long.parseLong(Long.java:601)
  at java.lang.Long.valueOf(Long.java:803)
  at io.swagger.models.parameters.AbstractSerializableParameter.getExample(AbstractSerializableParameter.java:412)
  at sun.reflect.GeneratedMethodAccessor186.invoke(Unknown Source)
  at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
  at java.lang.reflect.Method.invoke(Method.java:498)
  at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:689)
  at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:755)
  at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:178)
  at com.fasterxml.jackson.databind.ser.impl.IndexedListSerializer.serializeContents(IndexedListSerializer.java:119)
  at com.fasterxml.jackson.databind.ser.impl.IndexedListSerializer.serialize(IndexedListSerializer.java:79)
  at com.fasterxml.jackson.databind.ser.impl.IndexedListSerializer.serialize(IndexedListSerializer.java:18)
  at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:728)
  at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:755)
  at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:178)
  at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:728)
  at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:755)
  at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:178)
  at com.fasterxml.jackson.databind.ser.std.MapSerializer.serializeFields(MapSerializer.java:726)
  at com.fasterxml.jackson.databind.ser.std.MapSerializer.serializeWithoutTypeInfo(MapSerializer.java:681)
  at com.fasterxml.jackson.databind.ser.std.MapSerializer.serialize(MapSerializer.java:637)
  at com.fasterxml.jackson.databind.ser.std.MapSerializer.serialize(MapSerializer.java:33)
  at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:728)
  at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:755)
  at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:178)
  at com.fasterxml.jackson.databind.ser.DefaultSerializerProvider._serialize(DefaultSerializerProvider.java:480)
  at com.fasterxml.jackson.databind.ser.DefaultSerializerProvider.serializeValue(DefaultSerializerProvider.java:319)
  at com.fasterxml.jackson.databind.ObjectMapper._writeValueAndClose(ObjectMapper.java:4409)
  at com.fasterxml.jackson.databind.ObjectMapper.writeValueAsString(ObjectMapper.java:3663)
  at springfox.documentation.spring.web.json.JsonSerializer.toJson(JsonSerializer.java:38)
  at springfox.documentation.swagger2.web.Swagger2Controller.getDocumentation(Swagger2Controller.java:105)
  at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
  at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
  at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
  at java.lang.reflect.Method.invoke(Method.java:498)
  at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:190)
  at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:138)
  at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:105)
  at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:878)
  at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:792)
  at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87)
  at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1040)
  at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:943)
  at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006)
  at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:898)
  at javax.servlet.http.HttpServlet.service(HttpServlet.java:626)
  at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883)
  at javax.servlet.http.HttpServlet.service(HttpServlet.java:733)
  at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)
  at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
  at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)
  at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
  at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
  at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100)
  at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119)
  at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
  at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
  at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93)
  at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119)
  at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
  at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
  at org.springframework.boot.actuate.metrics.web.servlet.WebMvcMetricsFilter.doFilterInternal(WebMvcMetricsFilter.java:93)
  at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119)
  at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
  at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
  at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201)
  at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119)
  at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
  at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
  at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202)
  at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:97)
  at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:542)
  at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:143)
  at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)
  at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:78)
  at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343)
  at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:374)
  at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65)
  at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:868)
  at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1590)
  at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
  at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
  at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
  at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
  at java.lang.Thread.run(Thread.java:748)

   @ApiOperation(value = "下拉查询常量定义", notes = "下拉查询常量定义")
    @ApiImplicitParams({
            @ApiImplicitParam(name = "regain", value = "重新获取", example = "0",paramType = "query", dataType = "int")
    })
    @GetMapping("/fieldDict/select")
    public Response select(@RequestParam(value = "regain", required = false) Integer regain) {
        return new Response(HttpRespCode.SUCCESS, fieldDictService.select(regain));
    }