Question

使用渲染插件时遇到一些问题。它总是返回一个空指针异常。我看到了类似的严重问题，但我找不到我错的地方。

我的模板代码：/views/appRetail/_report.gsp

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org /TR/xhtml1/DTD/xhtml1-strict.dtd">
<head>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta name="description" content="">
    <meta name="author" content="">
    <title>Welcome to Production !</title>
</head>
<html>
   <body>
    REPORT
   </body>
</html>

我的控制器代码：

class AppRetailController {

  def pdfRenderingService

  def renderFormPDF() {

    def apps = App.findAll()
    new File("test.pdf").withOutputStream { outputStream ->
        pdfRenderingService.render(template: '/appRetail/report', model: [apps:apps], outputStream)
    }
  }
}

这是stacktrace：

2015-04-17 10:31:54,552 [http-bio-8080-exec-4] ERROR   errors.GrailsExceptionResolver  - NullPointerException occurred when   processing request: [POST] /toolprod/appRetail/renderFormPDF
Stacktrace follows:
Message: null
Line | Method
->> 1281 | getPublicDeclaredMethods in java.beans.Introspector
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 
|   1141 | getTargetMethodInfo      in     ''
|    416 | getBeanInfo . . . . . .  in     ''
|    163 | getBeanInfo              in     ''
|     31 | init . . . . . . . . . . in     grails.plugin.rendering.document.RenderEnvironment
|     68 | with                     in     ''
|     60 | with . . . . . . . . . . in     ''
|     65 | generateXhtml            in     grails.plugin.rendering.document.XhtmlDocumentService
|     35 | createDocument . . . . . in     ''
|     36 | render                   in grails.plugin.rendering.RenderingService
|    348 | doCall . . . . . . . . . in     toolprod.AppRetailController$_renderFormPDF_closure1
|    347 | renderFormPDF            in toolprod.AppRetailController
|    198 | doFilter . . . . . . . . in grails.plugin.cache.web.filter.PageFragmentCachingFilter
|     63 | doFilter                 in     grails.plugin.cache.web.filter.AbstractFilter
|     82 | doFilterInternal . . . . in com.linkedin.grails.profiler.ProfilerFilter
|   1145 | runWorker                in java.util.concurrent.ThreadPoolExecutor
|    615 | run . . . . . . . . . .  in java.util.concurrent.ThreadPoolExecutor$Worker
^    744 | run                      in java.lang.Thread

以下是我使用的版本：

插件版本：编译＆＃34;：渲染：1.0.0＆＃34;
Grails版本：2.5.0

Answer 1

您需要在buildConfig文件中添加此依赖项：

dependencies {
    runtime 'org.springframework:spring-test:4.1.6.RELEASE'
}

Answer 2

从堆栈跟踪看起来withOutputStream关闭会导致一些混乱，但它在测试应用程序中对我有用。尝试运行grails clean和grails compile并重新运行该应用。如果这不能解决问题，请删除目标目录并运行clean并再次编译。

如果仍然存在问题，可以通过几种不同的方式生成PDF。您可以获取生成的OutputStream数组并自行编写，而不是将byte[]传递给iText来呈现PDF，例如。

def renderFormPDF() {
    def apps = App.findAll()
    ByteArrayOutputStream baos = pdfRenderingService.render(template: '/appRetail/report', model: [apps: apps])
    new File('test.pdf').withOutputStream { it.write baos.toByteArray() }
}

或

def renderFormPDF() {
    def apps = App.findAll()
    ByteArrayOutputStream baos = pdfRenderingService.render(template: '/appRetail/report', model: [apps: apps])
    new File('test.pdf') << baos.toByteArray()
}

Grails渲染插件的空指针异常

2 个答案: