I am looking for a way to export a JTable with data to a .csv file. But I didn't find a good method to do that. It works and generates the csv file. But There is a problem. When there is data in a jTable column like this,
|column 1|column 2|
-------------------
|Java, C#|PHP |
The result is,
column 1,column2,
Java,C#,PHP,
So the problem id there are only 2 columns and 2 data columns but for CSV file, there are 3 data columns. When importing that CSV file to the Excel sheet it is completely wrong. Data went to different locations.
So is there another way to do this in Java or any way to avoid this problem?
Thanks for the help in advance! Best Regards.
I use the following code.
public void ExportToCSVfile(JTable table) throws IOException, ClassNotFoundException
{
Writer writer = null;
DefaultTableModel defaultTableModel = (DefaultTableModel) table.getModel();
int Row = defaultTableModel.getRowCount();
int Col = defaultTableModel.getColumnCount();
try {
writer = new BufferedWriter(new OutputStreamWriter(new FileOutputStream("file.csv"), "utf-8"));
StringBuffer bufferHeader = new StringBuffer();
for (int j = 0; j < Col; j++) {
bufferHeader.append(defaultTableModel.getColumnName(j));
if (j!=Col) bufferHeader.append(", ");
}
writer.write(bufferHeader.toString() + "\r\n");
for (int i = 0 ; i < Row ; i++){
StringBuffer buffer = new StringBuffer();
for (int j = 0 ; j < Col ; j++){
buffer.append(defaultTableModel.getValueAt(i,j));
if (j!=Col) buffer.append(", ");
}
writer.write(buffer.toString() + "\r\n");
}
} finally {
writer.close();
}
}
So is there another way to do this in Java or any way to avoid this problem?
I don't know all the rules of a CSV formatted file but I believe for something this simple where a cell contains a "," you can just delimit the entire text of the cell.
So the ouput of your file should be:
column 1,column2,
"Java,C#",PHP,
This is easy to verify you just create a simple spreadsheet where the cell contains a comma and then you export the spreadsheet to a .csv file and check the format of the file in a text editor.
I think you can delimit all data with "..." even if it doesn't contain a comma but you will need to verify that.
So you need to modify your export code to include the delimiters.
Related
I am learning how to write in the xlsx file using Apache poi,Now in the below code i am using 2 array.
1.Month 2.Logging_Hours.
I am using Month array to assign the column name in the first row and it work fine for me.Now what i want the another Array in my code Logging_Hours print in each column but i am not getting the expected answer by using the below code.
For_Expected refer to the screen :"Expected_Xlsx"
For_Actual refer to the screen :"Actual_Xlsx"
public class Writing_xlsx {
public static void main(String[] args) throws IOException {
Workbook wb = new XSSFWorkbook();
Sheet sheet1=wb.createSheet("SheetOne");
String [] Month={"January" , "Feb", "March","Apr"};
int [] Logging_Hours={ 7 ,5, 9,10};
int f=0;
System.out.println(Month[0]);
Row r=sheet1.createRow(f);
for(int i=0;i<4;i++){
r.createCell(i).setCellValue(Month[i]);
}
for(int c=0;c<4;c++){}
int d=0;
while(d<4){
for(int rn=1;rn<=4;rn++) {
r=sheet1.createRow(rn);
r.createCell(d).setCellValue(Logging_Hours[rn-1]);
System.out.println(Logging_Hours[rn-1]);
}
d++;
}
FileOutputStream fileOut = new FileOutputStream("workbook.xlsx");
wb.write(fileOut);
fileOut.close();
wb.close();
}
}
For_Expected refer to the screen :"Expected_Xlsx"
For_Actual refer to the screen :"Actual_Xlsx"
Thank You in advance ,Sorry for the bad code i am just in a learning phase.
You will need two for loops (nested) to write the data, e.g.:
for (int rn = 1; rn <= 4; rn++) {
Row row = sheet1.createRow(rn);
for (int i = 0; i < 4; i++) {
row.createCell(i).setCellValue(Month[rn-1]);
}
}
Current for loop creates only one cell per row and writes the value into it whereas we need to write the values in all 4 cells per row.
I want to insert a table at a specific position with poi, the table is generated, but I find this table is not visible.
The generated table in doc is visible when previewing or editing this doc with macOS and its text tool, POI can read the table and content, too. I plan to upload 4 pictures to display the process, but I can only post 2 images, sorry for that.
#Test
public void exportDoc() throws Exception {
FileInputStream readFile = new FileInputStream(new File(readDoc));
FileOutputStream replaceFile = new FileOutputStream(new File(replaceDoc));
HWPFDocument document = new HWPFDocument(readFile);
Table table = WordUtil.insertNewTable(document,"${table}");
insertTableInDoc(table);
document.write(replaceFile);
readFile.close();
replaceFile.close();
}
private Table insertNewTable(HWPFDocument doc, String sourceValue) {
Range range = doc.getRange();
Table table = null;
for (int i = 0; i < range.numSections(); ++i) {
Section s = range.getSection(i);
for (int x = 0; x < s.numParagraphs(); x++) {
Paragraph p = s.getParagraph(x);
if (p.text().contains(sourceValue)) {
//remove target text
range.replaceText(sourceValue, "");
table = p.insertTableBefore((short) 3, 3);
return table;
}
}
}
return table;
}
private void insertTableInDoc(Table table) {
int count = 1;
for (int rowNum = 0; rowNum < table.numRows(); rowNum++) {
TableRow tableRow = table.getRow(rowNum);
for (int colNum = 0; colNum < tableRow.numCells(); colNum++) {
TableCell cell = tableRow.getCell(colNum);
Paragraph paragraph = cell.getParagraph(0);
CharacterRun characterRun = paragraph.getCharacterRun(0);
characterRun.insertBefore("number: " + count++);
}
}
}
PS:
I am sure this is not microsoft for mac 's problem, the generate table in doc at windows platform is not visible, too.
(First time to ask question, if anything wrong or my expression is not clear, please let me know and I will modify it without delay. Thanks)
With the current state of the HWPF project, you likely are out of luck when trying to insert content into a .doc file. Your best bet is to use a different format (docx).
I did not look at HWPF for the past year, so I may be wrong here regarding the current state of HWPF:
Some years ago I was developing a custom HWPF library for a client. The major goal for that custom library was the ability to modify .doc files and that Word can process the modified files correctly. Hence I know in how many levels modifying a .doc file can fail in the end. The public HWPF library is not able to handle many aspects of the .doc file format when it comes to modification (textboxes, two-byte character ranges, shape files, nested tables, ... to name a few).
To handle modification correctly, all the "features" of the specific .doc file must be supported by the library. So when there are shapes in the .doc file, HWPF must adjust the position tables of the shapes even when a simple text snippet is inserted and the shapes are not touched. If shapes are not handled, Word will crash when opening the output file.
So if you can, use docx or rtf. If it is an option, you might try one of the commercial libraries which are able to handle .doc files.
I am reading in a CSV file and putting each delimited element into a two-dimensional array. The code looks like this:
public DataProcess(String filename, String[][] contents, int n) {//n is 6 for contents, 5 for fiveMinContents
Scanner fileReader = null;
try {
fileReader = new Scanner(new File(filename));
} catch (FileNotFoundException ex) {
System.out.println(ex + " FILE NOT FOUND ");
}
fileReader.useDelimiter(",");
int rowIndex = 0;
while (fileReader.hasNext()) {
for (int j = 0; j < n; j++) {
contents[rowIndex][j] = fileReader.next();
System.out.println("At (" + rowIndex +", "+j+"): " +
contents[rowIndex][j]);
}
rowIndex++;
fileReader.nextLine();
}
}
I am not sure why it reads every other line of this particular CSV file because this is file 2/2 that is being read in this manner. The first one reads fine, but now this one skips every other line. Why would it work for one but not the other? I am running this on Eclipse's latest update.
I also checked out this answer and it did not help.
Because the last line of your loop reads a line and discards it. You need something like,
while (fileReader.hasNextLine()) {
String line = fileReader.nextLine();
contents[rowIndex] = fileReader.split(",\\s*");
System.out.println("At (" + rowIndex + "): "
+ Arrays.toString(contents[rowIndex]));
rowIndex++;
}
You could also print the multi-dimensional array with one call like
System.out.println(Arrays.deepToString(contents));
While the approach may work for you, it's not optimal. There are premade CSV readers for Java. One example is commons-csv:
Reader in = new FileReader("path/to/file.csv");
Iterable<CSVRecord> records = CSVFormat.EXCEL.parse(in);
for (CSVRecord record : records) {
String date = record.get(1);
String time = record.get(2);
// and so on, so forth
}
There are a small number of dependencies that have to be on your classpath. Hope that helps.
I found the issue to this problem.
First, I recommend using the external library that was suggested.
The issue was that since this second file was reading the entire row, whereas the first CSV file was reading what I wanted it to, but there was a column at the end of the file that I was ignoring. There must be a way that a CSV file is structured where the end of a row has a different delimiter or something along those lines--not sure. To fix this issue, I just added an extra column to the second file and I am not reading it in; it is just there.
In short, use an external CSV-reader library. If you don't want to do that, then just add a column directly after the last column in the file and do not read it.
I am having 2 issues using the apache POI to write data from a csv into an excel file.
The data consists of dates, and numbers
The issues are:
1) The numbers are written as strings.
2) Excel cannot read the date format (this messes the graphs up)
The code (that I received help with previously):
String name = "test";
Sheet sheet = wb.getSheet(name);
if (sheet == null) {
sheet = wb.createSheet(name);
}
int rowCount = 0;
Scanner scanner = new Scanner(new File("/tmp/" + name + ".csv"));
while (scanner.hasNextLine()) {
String[] rowData = scanner.nextLine().split(",");
for (int col = 0; col < rowData.length; col++) {
Row row = sheet.getRow(rowCount);
if (row == null)
row = sheet.createRow(rowCount);
Cell cell = row.getCell(col);
if (cell == null) {
cell = row.createCell(col);
}
cell.setCellValue(rowData[col]);
}
rowCount++;
}
wb.write(new FileOutputStream(excel));
}
1) I tried using Double.parseDouble(rowData[col]) when entering the data into the excel file. but this gives an empty string error. I even set the cell format with style.setDataFormat(format.getFormat("#,##0.0000")); but it still does not work
2) I tried using the date format cellStyle.setDataFormat(createHelper.createDataFormat().getFormat("m/d/yyyy hh:mm:ss")); but still the excel graphs can't read this format. (when I manually copy and paste from the csv file it works).
So basically, when copying data using the apache poi, none of the other data that relies on the copied cells is updated.
for example if a cell has a value of the average of 100 cells, and I manually copy data into those cells, it updates automatically. But when it copies through java, the cells do not update.
The following should do something more.
try {
double value = Double.parseDouble(rowData[col]);
cell.setCellValue(value);
} catch (NumberFormatException | NullPointerException e) {
String value = rowData[col];
cell.setCellValue(value);
}
(However you might not use Apache POI and straight copy the CSV file to a .xls, if
it is just a need for double-click reading by Excel.)
Hi i have a small problem and think i'm just not getting the correct syntax on one line of code. basically, i can write into my csv file and find a specific record using string tokenizer but it is not updating/editing the specified cells of that record. the record remains the same. please help....
I have used http://opencsv.sourceforge.net in java
Hi,
This is the code to update CSV by specifying row and column
/**
* Update CSV by row and column
*
* #param fileToUpdate CSV file path to update e.g. D:\\chetan\\test.csv
* #param replace Replacement for your cell value
* #param row Row for which need to update
* #param col Column for which you need to update
* #throws IOException
*/
public static void updateCSV(String fileToUpdate, String replace,
int row, int col) throws IOException {
File inputFile = new File(fileToUpdate);
// Read existing file
CSVReader reader = new CSVReader(new FileReader(inputFile), ',');
List<String[]> csvBody = reader.readAll();
// get CSV row column and replace with by using row and column
csvBody.get(row)[col] = replace;
reader.close();
// Write to CSV file which is open
CSVWriter writer = new CSVWriter(new FileWriter(inputFile), ',');
writer.writeAll(csvBody);
writer.flush();
writer.close();
}
This solution worked for me,
Cheers!
I used the below code where I will replace a string with another and it worked exactly the way I needed:
public static void updateCSV(String fileToUpdate) throws IOException {
File inputFile = new File(fileToUpdate);
// Read existing file
CSVReader reader = new CSVReader(new FileReader(inputFile), ',');
List<String[]> csvBody = reader.readAll();
// get CSV row column and replace with by using row and column
for(int i=0; i<csvBody.size(); i++){
String[] strArray = csvBody.get(i);
for(int j=0; j<strArray.length; j++){
if(strArray[j].equalsIgnoreCase("Update_date")){ //String to be replaced
csvBody.get(i)[j] = "Updated_date"; //Target replacement
}
}
}
reader.close();
// Write to CSV file which is open
CSVWriter writer = new CSVWriter(new FileWriter(inputFile), ',');
writer.writeAll(csvBody);
writer.flush();
writer.close();
}
You're doing something like this:
String line = readLineFromFile();
line.replace(...);
This is not editing the file, it's creating a new string from a line in the file.
String instances are immutable, so the replace call you're making returns a new string it does not modify the original string.
Either use a file stream that allows you to both read and write to the file - i.e. RandomAccessFile or (more simply) write to a new file then replace the old file with the new one
In psuedo code:
for (String line : inputFile) {
String [] processedLine = processLine(line);
outputFile.writeLine(join(processedLine, ","));
}
private String[] processLine(String line) {
String [] cells = line.split(","); // note this is not sufficient for correct csv parsing.
for (int i = 0; i < cells.length; i++) {
if (wantToEditCell(cells[i])) {
cells[i] = "new cell value";
}
}
return cells;
}
Also, please take a look at this question. There are libraries to help you deal with csv.
CSV file is just a file. It is not being changed if you are reading it.
So, write your changes!
You have 3 ways.
1
read line by line finding the cell you want to change.
change the cell if needed and composite new version of current line.
write the line into second file.
when you finished you have the source file and the result file. Now if you want you can remove the source file and rename the result file to source.
2
Use RandomAccess file to write into specific place of the file.
3
Use one of available implementations of CSV parser (e.g. http://commons.apache.org/sandbox/csv/)
It already supports what you need and exposes high level API.