swagger 报错问题记录

报错日志部分内容如下，看不出任何业务代码的问题：

java.lang.NullPointerException: null
    at springfox.documentation.swagger2.mappers.RequestParameterMapper.mapParameter(RequestParameterMapper.java:55)
    at springfox.documentation.swagger2.mappers.ServiceModelToSwagger2Mapper.beforeMappingOperations(ServiceModelToSwagger2Mapper.java:125)
    at springfox.documentation.swagger2.mappers.ServiceModelToSwagger2MapperImpl.mapOperation(ServiceModelToSwagger2MapperImpl.java:109)
    at springfox.documentation.swagger2.mappers.ServiceModelToSwagger2Mapper.mapOperations(ServiceModelToSwagger2Mapper.java:270)
    at springfox.documentation.swagger2.mappers.ServiceModelToSwagger2Mapper.lambda$mapApiListings$2(ServiceModelToSwagger2Mapper.java:258)
    at java.util.stream.ForEachOps$ForEachOp$OfRef.accept(ForEachOps.java:184)
    at java.util.ArrayList$ArrayListSpliterator.forEachRemaining(ArrayList.java:1382)
    at java.util.stream.ReferencePipeline$Head.forEach(ReferencePipeline.java:580)
    at java.util.stream.ReferencePipeline$7$1.accept(ReferencePipeline.java:270)
    at java.util.TreeMap$ValueSpliterator.forEachRemaining(TreeMap.java:2897)
    at java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:481)
    at java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:471)
    at java.util.stream.ForEachOps$ForEachOp.evaluateSequential(ForEachOps.java:151)
    at java.util.stream.ForEachOps$ForEachOp$OfRef.evaluateSequential(ForEachOps.java:174)
    at java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
    at java.util.stream.ReferencePipeline.forEachOrdered(ReferencePipeline.java:423)
    at springfox.documentation.swagger2.mappers.ServiceModelToSwagger2Mapper.mapApiListings(ServiceModelToSwagger2Mapper.java:253)
    at springfox.documentation.swagger2.mappers.ServiceModelToSwagger2MapperImpl.mapDocumentation(ServiceModelToSwagger2MapperImpl.java:48)
    at springfox.documentation.swagger2.web.Swagger2ControllerWebMvc.getDocumentation(Swagger2ControllerWebMvc.java:99)
    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:205)
    at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:150)
    at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:117)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:895)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:808)
    at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87)
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1067)
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:963)
    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:655)
    at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:764)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:227)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)

原因是controller 中的参数与swagger的参数定义对应不上导致，所以获取参数报错，此处swagger做的不好，应当提示一下具体是哪个类的那个接口有问题，如果代码改动比较多不太好排查：

  @ApiImplicitParams({
            @ApiImplicitParam(name = "id", value = "编号", required = true, example = "1024", dataTypeClass = Long.class),
            @ApiImplicitParam(name = "comment", value = "意见说明", required = false, example = "1024", dataTypeClass = String.class)
    })
    public CommonResult<Boolean> method1(@RequestParam("id") Long id, @RequestParam(value = "userComment", required = false) String comment) {
    ...
    return success(true);
    }

如上标注部分，comment与userComment对应不上导致，改成一致即可。

 看来还是将request参数都封装成VO对象方便，修改属性名不容易出错