做的项目是前后端分离的，刚完成一个列表功能，写好了前端代码，启动后端后，前端没有报错，但是在浏览器中控制台不印不出来，显示如图
请求失败！！！
然后再看idea中控制台报错了
测试的时候idea中报这样的错误 org.springframework.web.method.annotation.MethodArgumentTypeMismatchException: Failed to convert value of type 'java.lang.String' to required type 'java.lang.Long'; nested exception is java.lang.NumberFormatException: For input string: "undefined"
百度说是方法参数类型不匹配异常！未能转换类型“”的值java.lang.String文件'至所需类型'java.lang.Long文件'，我立马查看了后端参数中传的值，就两个Long类型的，
@PostMapping("pageReacherCondition/{current}/{limit}")（@PathVariable Long current, @PathVariable Long limit,）但是传到前端用vue写的没有参数类型，怎么会错呢！！！， 参数不是问题所在！！，接着又去了网页中请求的资源都加载了吗，果然！
Request URL:http://localhost:8001/edu/teacher/pageReacherCondition/undefined/10中请求的路径没有显示，这才注意到nested exception is java.lang.NumberFormatException: For input string: "undefined"这个错误。这是一个分页请求路径后面应该是current/limit--当前页/记录数，因为这个current没有得到值，所以请求数据失败，去前面端页面查看：
data(){//定义变量初始化
return{
list:null,//查询之后接口返回的集合
total:0,//总记录数
current:1,//当前页
limit:10,//每页记录数
teacherQuery:{}//条件封装对象
}
},
created(){//页面渲染之前执行，调用method中的方法
this.getList()
},
methods:{//创建具体的方法，调用teacher.js中定义的方法
getList(){
teacher.getTeacherListPage(this.page,this.limit,this.teacherQuery)//这里的参数名一定要和data里面返回的一样
.then(response=>{//请求成功
//response接口返回数据
this.list=response.data.rows
this.total=response.data.total
console.log(response)
console.log(this.list)
console.log(this.total)
})
.catch(error=>{
console.log(error)
})
}
}
teacher.getTeacherListPage(this.page,this.limit,this.teacherQuery)在进行ajax请求时，与上面data初始化时得参数不一样，应该统一写成current！！！
错误很低级！细心就好
附异常源码：
org.springframework.web.method.annotation.MethodArgumentTypeMismatchException: Failed to convert value of type 'java.lang.String' to required type 'java.lang.Long'; nested exception is java.lang.NumberFormatException: For input string: "undefined"
at org.springframework.web.method.annotation.AbstractNamedValueMethodArgumentResolver.resolveArgument(AbstractNamedValueMethodArgumentResolver.java:133)
at org.springframework.web.method.support.HandlerMethodArgumentResolverComposite.resolveArgument(HandlerMethodArgumentResolverComposite.java:121)
at org.springframework.web.method.support.InvocableHandlerMethod.getMethodArgumentValues(InvocableHandlerMethod.java:167)
at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:134)
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:106)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:888)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:793)
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.doPost(FrameworkServlet.java:909)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:660)
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:741)
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.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:96)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:526)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343)
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:408)
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:861)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1579)
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)
Caused by: java.lang.NumberFormatException: For input string: "undefined"
at java.lang.NumberFormatException.forInputString(NumberFormatException.java:65)
at java.lang.Long.parseLong(Long.java:589)
at java.lang.Long.valueOf(Long.java:803)
at org.springframework.util.NumberUtils.parseNumber(NumberUtils.java:214)
at org.springframework.beans.propertyeditors.CustomNumberEditor.setAsText(CustomNumberEditor.java:115)
at org.springframework.beans.TypeConverterDelegate.doConvertTextValue(TypeConverterDelegate.java:429)
at org.springframework.beans.TypeConverterDelegate.doConvertValue(TypeConverterDelegate.java:402)
at org.springframework.beans.TypeConverterDelegate.convertIfNecessary(TypeConverterDelegate.java:155)
at org.springframework.beans.TypeConverterSupport.convertIfNecessary(TypeConverterSupport.java:73)
at org.springframework.beans.TypeConverterSupport.convertIfNecessary(TypeConverterSupport.java:53)
at org.springframework.validation.DataBinder.convertIfNecessary(DataBinder.java:693)
at org.springframework.web.method.annotation.AbstractNamedValueMethodArgumentResolver.resolveArgument(AbstractNamedValueMethodArgumentResolver.java:125)
... 47 more