I am trying to write data to a csv file with java, however when I try opening the produced file with excel I am getting an error saying the file is corrupt. Upon opening the file in notepad it looks to be formatted correctly so I'm not sure what the issue is. I am using the FileWriter class to output the data to the file.
FileWriter writer = new FileWriter("test.csv");
writer.append("ID");
writer.append(',');
writer.append("name");
writer.append(',');
...
writer.append('\n');
writer.flush();
writer.close();
Do I need to use some library in java in order to print to a csv file? I presumed you could just do this natively in java as long as you used the correct formatting.
Appreciate the help,
Shaw
This question is related to
java
excel
csv
export-to-csv
The answer is
Basically it's because MS Excel can't decide how to open the file with such content.
When you put ID as the first character in a Spreadsheet type file, it matches the specification of a SYLK file and MS Excel (and potentially other Spreadsheet Apps) try to open it as a SYLK file. But at the same time, it does not meet the complete specification of a SYLK file since rest of the values in the file are comma separated. Hence, the error is shown.
To solve the issue, change "ID" to "id" and it should work as expected.
This is weird. But, yeah!
Also trying to minimize file access by using file object less.
I tested and the code below works perfect.
import java.io.File;
import java.io.FileNotFoundException;
import java.io.PrintWriter;
public class CsvWriter {
public static void main(String[] args) {
try (PrintWriter writer = new PrintWriter(new File("test.csv"))) {
StringBuilder sb = new StringBuilder();
sb.append("id,");
sb.append(',');
sb.append("Name");
sb.append('\n');
sb.append("1");
sb.append(',');
sb.append("Prashant Ghimire");
sb.append('\n');
writer.write(sb.toString());
System.out.println("done!");
} catch (FileNotFoundException e) {
System.out.println(e.getMessage());
}
}
}
import java.io.File;
import java.io.FileNotFoundException;
import java.io.PrintWriter;
public class CsvFile {
public static void main(String[]args){
PrintWriter pw = null;
try {
pw = new PrintWriter(new File("NewData.csv"));
} catch (FileNotFoundException e) {
e.printStackTrace();
}
StringBuilder builder = new StringBuilder();
String columnNamesList = "Id,Name";
// No need give the headers Like: id, Name on builder.append
builder.append(columnNamesList +"\n");
builder.append("1"+",");
builder.append("Chola");
builder.append('\n');
pw.write(builder.toString());
pw.close();
System.out.println("done!");
}
}
I think this is a simple code in java which will show the string value in CSV after compile this code.
public class CsvWriter {
public static void main(String args[]) {
// File input path
System.out.println("Starting....");
File file = new File("/home/Desktop/test/output.csv");
try {
FileWriter output = new FileWriter(file);
CSVWriter write = new CSVWriter(output);
// Header column value
String[] header = { "ID", "Name", "Address", "Phone Number" };
write.writeNext(header);
// Value
String[] data1 = { "1", "First Name", "Address1", "12345" };
write.writeNext(data1);
String[] data2 = { "2", "Second Name", "Address2", "123456" };
write.writeNext(data2);
String[] data3 = { "3", "Third Name", "Address3", "1234567" };
write.writeNext(data3);
write.close();
} catch (Exception e) {
// TODO: handle exception
e.printStackTrace();
}
System.out.println("End.");
}
}
private static final String FILE_HEADER ="meter_Number,latestDate";
private static final String COMMA_DELIMITER = ",";
private static final String NEW_LINE_SEPARATOR = "\n";
static SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM-dd HH:m m:ss");
private void writeToCsv(Map<String, Date> meterMap) {
try {
Iterator<Map.Entry<String, Date>> iter = meterMap.entrySet().iterator();
FileWriter fw = new FileWriter("smaple.csv");
fw.append(FILE_HEADER.toString());
fw.append(NEW_LINE_SEPARATOR);
while (iter.hasNext()) {
Map.Entry<String, Date> entry = iter.next();
try {
fw.append(entry.getKey());
fw.append(COMMA_DELIMITER);
fw.append(formatter.format(entry.getValue()));
fw.append(NEW_LINE_SEPARATOR);
} catch (Exception e) {
e.printStackTrace();
} finally {
iter.remove();
}
}
} catch (Exception e) {
e.printStackTrace();
}
}
I see you already have a answer but here is another answer, maybe even faster A simple class to pass in a List of objects and retrieve either a csv or excel or password protected zip csv or excel. https://github.com/ernst223/spread-sheet-exporter
SpreadSheetExporter spreadSheetExporter = new SpreadSheetExporter(List<Object>, "Filename");
File fileCSV = spreadSheetExporter.getCSV();
Answer for this question is good if you want to overwrite your file everytime you rerun your program, but if you want your records to not be lost at rerunning your program, you may want to try this
public void writeAudit(String actionName) {
String whereWrite = "./csvFiles/audit.csv";
try {
FileWriter fw = new FileWriter(whereWrite, true);
BufferedWriter bw = new BufferedWriter(fw);
PrintWriter pw = new PrintWriter(bw);
Date date = new Date();
pw.println(actionName + "," + date.toString());
pw.flush();
pw.close();
} catch (FileNotFoundException e) {
System.out.println(e.getMessage());
} catch (IOException e) {
e.printStackTrace();
}
}
String filepath="/tmp/employee.csv";
FileWriter sw = new FileWriter(new File(filepath));
CSVWriter writer = new CSVWriter(sw);
writer.writeAll(allRows);
String[] header= new String[]{"ErrorMessage"};
writer.writeNext(header);
List<String[]> errorData = new ArrayList<String[]>();
for(int i=0;i<1;i++){
String[] data = new String[]{"ErrorMessage"+i};
errorData.add(data);
}
writer.writeAll(errorData);
writer.close();
Source: Stackoverflow.com