Question

我正在将我的应用程序从Grails 2.4.4升级到3.3.1，并且无法下载zip文件。在写入response.outputStream时，我似乎得到了一个Null Pointer Exception。这是我在Grails 2.4.4中使用的代码：

File f = new File(fname)
if (!f.exists()) {
     flash.message = "Unable to retrieve file ${f.getName()}"
     redirect(action: "...")
     return
}
response.setContentType("application/octet-stream")
response.setHeader("Content-disposition", "attachment; filename*=UTF-8''" + f.getName())           
f.withInputStream { response.outputStream << it }
null

这是我得到的错误：

ERROR --- [nio-8080-exec-9] o.g.web.errors.GrailsExceptionResolver   : NullPointerException occurred when processing request: [GET] /myapp/mycontroller/myaction - 
Stacktrace follows:

java.lang.reflect.InvocationTargetException: null
        at org.grails.core.DefaultGrailsControllerClass$ReflectionInvoker.invoke(DefaultGrailsControllerClass.java:211)
        at org.grails.core.DefaultGrailsControllerClass.invoke(DefaultGrailsControllerClass.java:188)
        at org.grails.web.mapping.mvc.UrlMappingsInfoHandlerAdapter.handle(UrlMappingsInfoHandlerAdapter.groovy:90)
        at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:967)
        at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:901)
        at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970)
        at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:861)
        at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846)
        at org.springframework.boot.web.filter.ApplicationContextHeaderFilter.doFilterInternal(ApplicationContextHeaderFilter.java:55)
        at com.mrhaki.grails.plugin.xframeoptions.web.XFrameOptionsFilter.doFilterInternal(XFrameOptionsFilter.groovy:70)
        at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:317)
        at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.invoke(FilterSecurityInterceptor.java:127)
        at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.doFilter(FilterSecurityInterceptor.java:91)
        at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
        at org.springframework.security.web.access.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:114)
        at grails.plugin.springsecurity.web.UpdateRequestContextHolderExceptionTranslationFilter.doFilter(UpdateRequestContextHolderExceptionTranslationFilter.groovy:64)
        at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
        at grails.plugin.springsecurity.web.filter.GrailsAnonymousAuthenticationFilter.doFilter(GrailsAnonymousAuthenticationFilter.groovy:54)
        at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
        at org.springframework.security.web.authentication.rememberme.RememberMeAuthenticationFilter.doFilter(RememberMeAuthenticationFilter.java:158)
        at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
        at org.springframework.security.web.servletapi.SecurityContextHolderAwareRequestFilter.doFilter(SecurityContextHolderAwareRequestFilter.java:170)
        at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
        at org.springframework.security.web.authentication.AbstractAuthenticationProcessingFilter.doFilter(AbstractAuthenticationProcessingFilter.java:200)
        at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
        at grails.plugin.springsecurity.web.authentication.logout.MutableLogoutFilter.doFilter(MutableLogoutFilter.groovy:64)
        at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
        at org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:105)
        at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
        at grails.plugin.springsecurity.web.SecurityRequestHolderFilter.doFilter(SecurityRequestHolderFilter.groovy:58)
        at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
        at org.springframework.security.web.FilterChainProxy.doFilterInternal(FilterChainProxy.java:214)
        at org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:177)
        at org.grails.web.servlet.mvc.GrailsWebRequestFilter.doFilterInternal(GrailsWebRequestFilter.java:77)
        at org.grails.web.filters.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:67)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
        at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.NullPointerException: null
        at java.beans.Introspector.getPublicDeclaredMethods(Introspector.java:1337)
        at java.beans.Introspector.getTargetMethodInfo(Introspector.java:1197)
        at java.beans.Introspector.getBeanInfo(Introspector.java:426)
        at java.beans.Introspector.getBeanInfo(Introspector.java:173)

Answer 1

我使用Grails 3成功了以下方法

def download() {
    def file = new File( grailsApplication.config.uploadDir + File.separatorChar + params.fileName )
    response.setContentType( "application/octet-stream" )
    response.setHeader("Content-disposition", "attachment;filename=\"${file.name}\"")
    response.outputStream << file.bytes
    }

Answer 2

问题在于我的build.gradle文件。我在我的依赖项部分之前有这一行（准备构建一个在外部Tomcat 7下运行的战争），但我目前正通过grails run-app运行我的应用程序：

ext['tomcat.version'] = '7.0.77'

删除此行后，我的原始代码有效。

在Grails 3.3.1中下载zip文件时出现问题

2 个答案: