When the project is started and the browser opens the swagger document, the following error is always reported, but the document and the program are normal.

java.lang.NumberFormatException: For input string: ""
	at java.lang.NumberFormatException.forInputString(NumberFormatException.java:65) ~[na:1.8.0_25]
	at java.lang.Long.parseLong(Long.java:601) ~[na:1.8.0_25]
	at java.lang.Long.valueOf(Long.java:803) ~[na:1.8.0_25]
	at io.swagger.models.parameters.AbstractSerializableParameter.getExample(AbstractSerializableParameter.java:412) ~[swagger-models-1.5.20.jar:1.5.20]
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_25]
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_25]
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_25]
	at java.lang.reflect.Method.invoke(Method.java:483) ~[na:1.8.0_25]
	at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:689) [jackson-databind-2.11.0.jar:2.11.0]
	at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:723) [jackson-databind-2.11.0.jar:2.11.0]
	at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:166) [jackson-databind-2.11.0.jar:2.11.0]
	at com.fasterxml.jackson.databind.ser.impl.IndexedListSerializer.serializeContents(IndexedListSerializer.java:119) [jackson-databind-2.11.0.jar:2.11.0]
	at com.fasterxml.jackson.databind.ser.impl.IndexedListSerializer.serialize(IndexedListSerializer.java:79) [jackson-databind-2.11.0.jar:2.11.0]
	at com.fasterxml.jackson.databind.ser.impl.IndexedListSerializer.serialize(IndexedListSerializer.java:18) [jackson-databind-2.11.0.jar:2.11.0]
	at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:728) [jackson-databind-2.11.0.jar:2.11.0]
	at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:723) [jackson-databind-2.11.0.jar:2.11.0]
	at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:166) [jackson-databind-2.11.0.jar:2.11.0]
	at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:728) [jackson-databind-2.11.0.jar:2.11.0]
	at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:723) [jackson-databind-2.11.0.jar:2.11.0]
	at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:166) [jackson-databind-2.11.0.jar:2.11.0]
	at com.fasterxml.jackson.databind.ser.std.MapSerializer.serializeOptionalFields(MapSerializer.java:786) [jackson-databind-2.11.0.jar:2.11.0]
	at com.fasterxml.jackson.databind.ser.std.MapSerializer.serializeWithoutTypeInfo(MapSerializer.java:677) [jackson-databind-2.11.0.jar:2.11.0]
	at com.fasterxml.jackson.databind.ser.std.MapSerializer.serialize(MapSerializer.java:637) [jackson-databind-2.11.0.jar:2.11.0]
	at com.fasterxml.jackson.databind.ser.std.MapSerializer.serialize(MapSerializer.java:33) [jackson-databind-2.11.0.jar:2.11.0]
	at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:728) [jackson-databind-2.11.0.jar:2.11.0]
	at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:723) [jackson-databind-2.11.0.jar:2.11.0]
	at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:166) [jackson-databind-2.11.0.jar:2.11.0]
	at com.fasterxml.jackson.databind.ser.DefaultSerializerProvider._serialize(DefaultSerializerProvider.java:480) [jackson-databind-2.11.0.jar:2.11.0]
	at com.fasterxml.jackson.databind.ser.DefaultSerializerProvider.serializeValue(DefaultSerializerProvider.java:319) [jackson-databind-2.11.0.jar:2.11.0]
	at com.fasterxml.jackson.databind.ObjectMapper._configAndWriteValue(ObjectMapper.java:4374) [jackson-databind-2.11.0.jar:2.11.0]
	at com.fasterxml.jackson.databind.ObjectMapper.writeValueAsString(ObjectMapper.java:3629) [jackson-databind-2.11.0.jar:2.11.0]
	at springfox.documentation.spring.web.json.JsonSerializer.toJson(JsonSerializer.java:38) [springfox-spring-web-3.0.0.jar:3.0.0]
	at springfox.documentation.swagger2.web.Swagger2ControllerWebMvc.getDocumentation(Swagger2ControllerWebMvc.java:106) [springfox-swagger2-3.0.0.jar:3.0.0]
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_25]
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_25]
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_25]
	at java.lang.reflect.Method.invoke(Method.java:483) ~[na:1.8.0_25]
	at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:190) [spring-web-5.2.7.RELEASE.jar:5.2.7.RELEASE]
	at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:138) [spring-web-5.2.7.RELEASE.jar:5.2.7.RELEASE]
	at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:105) [spring-webmvc-5.2.7.RELEASE.jar:5.2.7.RELEASE]
	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:879) [spring-webmvc-5.2.7.RELEASE.jar:5.2.7.RELEASE]
	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:793) [spring-webmvc-5.2.7.RELEASE.jar:5.2.7.RELEASE]
	at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) [spring-webmvc-5.2.7.RELEASE.jar:5.2.7.RELEASE]
	at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1040) [spring-webmvc-5.2.7.RELEASE.jar:5.2.7.RELEASE]
	at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:943) [spring-webmvc-5.2.7.RELEASE.jar:5.2.7.RELEASE]
	at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006) [spring-webmvc-5.2.7.RELEASE.jar:5.2.7.RELEASE]
	at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:898) [spring-webmvc-5.2.7.RELEASE.jar:5.2.7.RELEASE]
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:634) [servlet-api.jar:na]
	at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883) [spring-webmvc-5.2.7.RELEASE.jar:5.2.7.RELEASE]
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:741) [servlet-api.jar:na]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) [tomcat-embed-core-9.0.36.jar:9.0.36]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [tomcat-embed-core-9.0.36.jar:9.0.36]
	at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) [tomcat-embed-websocket-9.0.36.jar:9.0.36]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [tomcat-embed-core-9.0.36.jar:9.0.36]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [tomcat-embed-core-9.0.36.jar:9.0.36]
	at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100) [spring-web-5.2.7.RELEASE.jar:5.2.7.RELEASE]
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) [spring-web-5.2.7.RELEASE.jar:5.2.7.RELEASE]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [tomcat-embed-core-9.0.36.jar:9.0.36]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [tomcat-embed-core-9.0.36.jar:9.0.36]
	at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93) [spring-web-5.2.7.RELEASE.jar:5.2.7.RELEASE]
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) [spring-web-5.2.7.RELEASE.jar:5.2.7.RELEASE]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [tomcat-embed-core-9.0.36.jar:9.0.36]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [tomcat-embed-core-9.0.36.jar:9.0.36]
	at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201) [spring-web-5.2.7.RELEASE.jar:5.2.7.RELEASE]
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) [spring-web-5.2.7.RELEASE.jar:5.2.7.RELEASE]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [tomcat-embed-core-9.0.36.jar:9.0.36]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [tomcat-embed-core-9.0.36.jar:9.0.36]
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202) [tomcat-embed-core-9.0.36.jar:9.0.36]
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) [tomcat-embed-core-9.0.36.jar:9.0.36]
	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:541) [tomcat-embed-core-9.0.36.jar:9.0.36]
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139) [tomcat-embed-core-9.0.36.jar:9.0.36]
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) [tomcat-embed-core-9.0.36.jar:9.0.36]
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74) [tomcat-embed-core-9.0.36.jar:9.0.36]
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343) [tomcat-embed-core-9.0.36.jar:9.0.36]
	at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:373) [tomcat-embed-core-9.0.36.jar:9.0.36]
	at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65) [tomcat-embed-core-9.0.36.jar:9.0.36]
	at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:868) [tomcat-embed-core-9.0.36.jar:9.0.36]
	at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1590) [tomcat-embed-core-9.0.36.jar:9.0.36]
	at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) [tomcat-embed-core-9.0.36.jar:9.0.36]
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) [na:1.8.0_25]
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) [na:1.8.0_25]
	at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) [tomcat-embed-core-9.0.36.jar:9.0.36]
	at java.lang.Thread.run(Thread.java:745) [na:1.8.0_25]

2. Cause of the problem:

1. View error log

2. Tracking problems

3. Breakpoint restore judgment

4. Error code found

5. The core of the problem

There is a problem with the annotation information of the property. The empty string ” cannot be converted to Number.

    /**
     * Message
     */
    @ResponseBody
    @ApiOperation(value = "Get order configuration table information based on ID")
    @ApiImplicitParams(@ApiImplicitParam(name = "id",value = "int type",dataType = "int",required = true))
    @RequestMapping(value = "/info/{id}",method = RequestMethod.GET)
    public R info(@PathVariable("id") Integer id){
		ApsOrderConfigEntity apsOrderConfig = apsOrderConfigService.getById(id);

        return R.ok().put("apsOrderConfig", apsOrderConfig);
    }

3. Problem solving

1. Remove the annotation directly

    /**
     * Message
     */
    @ResponseBody
    @ApiOperation(value = "Get order configuration table information based on ID")
//    @ApiImplicitParams(@ApiImplicitParam(name = "id",value = "int type",dataType = "int",required = true))
    @RequestMapping(value = "/info/{id}",method = RequestMethod.GET)
    public R info(@PathVariable("id") Integer id){
		ApsOrderConfigEntity apsOrderConfig = apsOrderConfigService.getById(id);

        return R.ok().put("apsOrderConfig", apsOrderConfig);
    }

2. Add example = "1"

    /**
     * Message
     */
    @ResponseBody
    @ApiOperation(value = "Get order configuration table information based on ID")
    @ApiImplicitParams(@ApiImplicitParam(name = "id",value = "int type",dataType = "int",required = true,example = "1"))
    @RequestMapping(value = "/info/{id}",method = RequestMethod.GET)
    public R info(@PathVariable("id") Integer id){
		ApsOrderConfigEntity apsOrderConfig = apsOrderConfigService.getById(id);

        return R.ok().put("apsOrderConfig", apsOrderConfig);
    }