Java - Writing strings to a CSV file

Question

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

User · Answer

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 lt Object gt    quot Filename quot    File fileCSV   spreadSheetExporter getCSV

User · Answer

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 lt String   gt  errorData   new ArrayList lt String   gt         for int i 0 i lt 1 i             String   data   new String    ErrorMessage  i           errorData add data             writer writeAll errorData        writer close

User · Answer

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 lt String  Date gt  meterMap            try               Iterator lt Map Entry lt String  Date gt  gt  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 lt String  Date gt  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

User · Answer

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

User · Answer

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

User · Answer

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

User · Answer

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  quot ID quot  to  quot id quot  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  quot test csv quot              StringBuilder sb   new StringBuilder          sb append  quot id  quot          sb append             sb append  quot Name quot          sb append   n           sb append  quot 1 quot          sb append             sb append  quot Prashant Ghimire quot          sb append   n           writer write sb toString            System out println  quot done  quot           catch  FileNotFoundException e          System out println e getMessage

[java] Java - Writing strings to a CSV file

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