无法找出为什么我得到空指针异常，任何人都可以帮助我吗？

Question

我的任务是上传图片并向用户显示图片路径，我有以下代码片段但它没有显示图片的路径，而是在存储路径的位置抛出空指针异常，虽然我把通用作为默认路径

  try {
            String storagePath ="generic";
            //String storagePath ="";
            if(storagePath!= null)
            {
            if (fileType.equalsIgnoreCase("emailTemplateImagePathUrl")
                    || fileType.equalsIgnoreCase("images"))
                storagePath = configurationSettings
                        .getEmailTemplateImagePathUrl();
            else if (fileType.equalsIgnoreCase("profileImagePathUrl"))
                storagePath = configurationSettings.getProfileImagePathUrl();
            else if (fileType.equalsIgnoreCase("imagePathUrl"))
                storagePath = configurationSettings.getImagePathUrl();
            else if (fileType.equalsIgnoreCase("postsImagePathUrl"))
                storagePath = configurationSettings.getPostsImagePathUrl();
            else if (fileType.equalsIgnoreCase("mantrasImagePathUrl"))
                storagePath = configurationSettings.getMantrasImagePathUrl();
            else if (fileType.equalsIgnoreCase("zodiacSignImagePathUrl"))
                storagePath = configurationSettings.getZodiacSignImagePathUrl();
            else if (fileType.equalsIgnoreCase("assetsBaseURL"))
                storagePath = configurationSettings.getAssetsBaseURL();
            else if (fileType.equalsIgnoreCase("assetsFolderName"))
                storagePath = configurationSettings.getAssetsFolderName();
            else if (fileType.equalsIgnoreCase("imagesFolderName"))
                storagePath = configurationSettings.getImagesFolderName();
            else if (fileType.equalsIgnoreCase("templeAssetsPrimaryFolderName"))
                storagePath = configurationSettings
                        .getTempleAssetsPrimaryFolderName();
            else if (fileType.equalsIgnoreCase("templeGalleryFolderName"))
                storagePath = configurationSettings
                        .getTempleGalleryFolderName();
            else if (fileType.equalsIgnoreCase("servicesFolderName"))
                storagePath = configurationSettings.getServicesFolderName();
            else if (fileType.equalsIgnoreCase("nearByFolderName"))
                storagePath = configurationSettings.getNearByFolderName();
            else if (fileType.equalsIgnoreCase("thumbnailsFolderName"))
                storagePath = configurationSettings.getThumbnailsFolderName();

            //String folderName = "C:\Users\Anupd\workspace2\Devalayam\WebContent\" + storagePath + "\" + fileName;
            String folderName = "C:\Users\Anupd\workspace2\Devalayam\WebContent\" + storagePath + "\" + fileName;
            System.out.println(storagePath);
            System.out.println(folderName);
            }
            //String uploadFileLocation = folderName + storagePath + fileName;
            String uploadFileLocation = storagePath ;
            System.out.println(uploadFileLocation);
            OutputStream out = new FileOutputStream(
                    new File(uploadFileLocation));

            int read = 0;
            byte[] bytes = new byte[1024];
            while ((read = uploadInputStream.read(bytes)) != -1) {
                out.write(bytes, 0, read);
            }
            uploadInputStream.close();
            out.flush();
            out.close();

            // 
            out = null;
            System.gc();

            File file = new File(uploadFileLocation);



            mapObject.put("fileName", fileName);
            mapObject.put("fileType", fileType);

            String strLong = Long.toString(file.getTotalSpace());

            mapObject.put("fileSize",strLong);
            } catch (IOException e) {
            e.printStackTrace();
        }
        return g.toJson(mapObject);

&操作是空

C:\Users\Anupd\workspace2\Devalayam\WebContent\nullf96f04-169b-47e4-9128-a326adfd2e1a-medium.jpeg
null

提前致谢

Answer 1

在您的 ide 中设置调试断点（或者可以在每个 if 块中设置打印语句），并单步执行每个 if 循环。它会给你一个特定的点，它给你空指针异常。

Answer 2

您的代码不完整，有很多未定义的变量 - 那么就无法确定 NPE 的确切来源。可能性是：

fileType
configurationSettings
uploadInputStream
mapObject

检查堆栈跟踪，它应该会告诉您错误的来源。

无法找出为什么我得到空指针异常，任何人都可以帮助我吗？

Cant find out why i'm getting null pointer exception, can anybody help me?

java

io

rest

image