小编Aks*_*ain的帖子

我试图从Android中的任何捕获图像中提取文本.所以我创建了一个Intent来访问相机并启动它startActivityForResult.

这是我的onActivityResult代码:

protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    if(requestCode == REQUEST_IMAGE_CAPTURE && resultCode == RESULT_OK) {
        String state = Environment.getExternalStorageState();
        if (Environment.MEDIA_MOUNTED.equals(state)) {
            Bundle extras = data.getExtras();
            Bitmap bitmap = (Bitmap) extras.get("data");
            TextView res = (TextView) findViewById(R.id.hello);
            //imageView.setImageBitmap(imageBitmap);
            //Image image = ImageIO.read(imageFile);
            //BufferedImage buffimg = (BufferedImage) image;
            //BufferedImage img = ImageHelper.convertImageToGrayscale(buffimg);
            //ITesseract instance = new Tesseract();  // JNA Interface Mapping
            //ITesseract instance = new Tesseract1(); // JNA Direct Mapping

            //TessDataManager.initTessTrainedData(context);
   if(isStoragePermissionGranted() == true) …

我昨天刚开始学习蜂巢,我不得不改变蜂巢中的一个列的类型.我想问一下列类型的更改是否对它们有某种限制因为我只能做特定类型的更改,比如我可以将int转换为double,string转换为double,double转换为string但是我不能将字符串更改为int,double到int.

ALTER TABLE student CHANGE rollno rollno int;
FAILED: Execution Error, return code 1 from org.apache.hadoop.hive.ql.exec.DDLTask. Unable to alter table. The following columns have types incompatible with the existing columns in their respective positions :
rollno

hive> DESCRIBE FORMATTED student
> ;
OK
# col_name              data_type               comment             

rollno                  int                                         
name                    string                                      
phno                    string                                      
city                    string   

    ALTER TABLE student CHANGE rollno rollno double;
OK
Time taken: 0.144 seconds

ALTER TABLE student CHANGE rollno rollno int;

FAILED: Execution Error, return code 1 …