Parsing Excel file without Apache POI

问题:

I know that we can use Apache POI to parse an Excel file and get data. But I heard of a strange thing that excel file can be passed in a similar way we parse CSV (Like just read the file from file Stream and separate each column value with a "comma" separator). When we parse Excel we have to use tab as a delimiter. Is it possible? If yes then why Apache has come up with such a complicated framework. I am puzzled. Can someone help me?

回答1:

CSV is a text format, so it can be parsed using the delimiters. Old Excel is a binary and proprietary format so it needs clever decoding. The new Excel format is zipped XMLs, but one should also understand the structure of this document before it could be transformed into something as simple as reading cells one by one. So the answer to your question is no, you'll need to use Apache POI, and also - there's nothing wrong with that.

As a side note, on the path to become a good developer you will need to learn to do a bit of your own research before looking for help. Get your hands dirty is the best way to learn things.

回答2:

You've probably confused what you've heard, or the person telling you was confused.

Some parts of Excel files can be stored (somewhat) as CSV files as the tabular data structure fits well within a CSV file format. However, if you save in CSV format then you just get plain text in each cell - you lose all formatting information, any graphs, multiple worksheets and so on.

The native XLS excel format is what Apache POI works with, and so can handle everything in excel, not just restrictive plain text in certain cells. CSV files have their uses but they're definitely not a straight replacement for normal Excel files.

回答3:

i tried to read/write excel file without using any external JAR like POI or any other. I am able to write file as xls format. Here is my Code

FileWriter fwriter = new FileWriter(file,true);
writer = new BufferedWriter(fwriter);
writer.newLine();
writer.write("a"    + "\t");
writer.write("b"    + "\t");
writer.write("c"    + "\t");
writer.write("d"    + "\t");
writer.write("e"    + "\t");
writer.write("f"    + "\t");

Reading File here is my code for reading

if(file != null) {
            BufferedReader reader = null;
            try {
                reader = new BufferedReader(new FileReader(file));
                String line;
                while((line = reader.readLine()) != null) {
                    String[] component = line.split("\\t");
                }
            } catch (FileNotFoundException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            } finally {
                if(reader != null) {
                    try {
                        reader.close();
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                }
            }

回答4:

InputStream is = new FileInputStream(new File(filepath));
        StreamingReader reader=null;
        try {
            reader = StreamingReader.builder()
                    .rowCacheSize(100)     
                    .bufferSize(4096)     
                    .sheetIndex(0)        
                    .read(is);
        } catch (Exception e1) {
            // TODO Auto-generated catch block
            e1.printStackTrace();
        }finally{
            is.close();
        }
        //pass here to reader and itrate it 
          for (Row row : reader) {
            if (row.getRowNum()!=0){
                for (Cell cell : row) {
              // write ur logic to store ur value 
                }

            }
        }