How to append only one line/row for each iteration in appending values to CSV file in Java

I am having some issues in terms of appending data into my CSV file, the problem is that whenever I try to append data into my CSV file on a second time, the second value which is appended to the CSV file comes with the first appended value. It's like it brings the existing value with it when appending to the CSV file. Thus, because of this issue, it results into an array index out of bounds exception, the data of the CSV file repeats the existing values along with the latest appended values, and also the first value is only displayed on my GUI table.

CSV File:

Table:

Here's my source code in writing and reading the CSV:

 public void writeCustomerCSV(){  // this creates a CSV file which stores the inputs of the user     try{         BufferedWriter bw = new BufferedWriter(new FileWriter("C:\\Users\\RALPH\\Documents\\Database Java CSV\\customers.csv",true)); // when I set append mode to true,  cust[read2DStringIndex][newVarIndexer] = fromfile[g] results to index array out of bounds to 10         StringBuilder sb = new StringBuilder();                   int y;         for(int x = 0; x < itemTo2D.length; x++){             if(itemTo2D[x][0] != null){             for(y = 0; y < itemTo2D[0].length; y++){                                    sb.append(itemTo2D[x][y]);                   sb.append(",");               }           }                sb.append("-");  //separation for rows             sb.append(",");  // separation for columns                       }                   bw.write(sb.toString());         bw.close();               }  catch (Exception ex){                 }         }        public void readCustomerCSV(){  // reads the contents of the CSV file             String [][] twoDArray = new String[10][7];      int read2DStringIndex = 0;      int newVarIndexer = 0;      DefaultTableModel tblmodelll = (DefaultTableModel) mainTable.getModel();  // table      String[] fromfile = {};   // 1d string for getting the columns(7 columns) of the CSV file      int ak = 0;      int sk = 0;           try{           BufferedReader br = new  BufferedReader(new FileReader("C:\\Users\\RALPH\\Documents\\Database Java CSV\\customers.csv"));           String line;                      while ((line = br.readLine()) != null){               fromfile = line.split(",");  //separates the columns by a comma                              for(int c = 0; c < fromfile.length; c++){                   if(fromfile[c].equals("-")){                       sk = 0;                                               ak++;                                              if(c > 0){                           if(!fromfile[c-1].equals("-")){                               id = id + 1;                                                          }                                                  }                                                                                                             } else{                       twoDArray[ak][sk] = fromfile[c];                                              sk++;                   }               }           }                                    } catch (Exception ex){                }            for(int g = 0; g < fromfile.length; g++){             if(fromfile[g].equals("-")){   //if there is a presence of a dash, it increments the read2DStringINdex (row index) of the 2D array                    read2DStringIndex++;                newVarIndexer = 0;             }           else{                   cust[read2DStringIndex][newVarIndexer] = fromfile[g];    //cust is the 2D array(declared universal) which is going to display the values to the table                   newVarIndexer++;                                 }               }                                for(int h = 0; h < cust.length; h++){  //prints cust (2D array) , just to check what data is being stored        for(int p = 0; p < cust[0].length; p++){            System.out.println(cust[h][p] + ",");         }     }                                          setrowcount = 0;        for(int r = 0; r < cust.length; r++){          if(setrowcount == 0){             tblmodelll.setRowCount(0);          }          try{                          if(cust[r][0].equals("null") == false){               tblmodelll.addRow(cust[r]);  //displays the cust(2D array) data to table              }          } catch(Exception e){                        }                   setrowcount++;      }              }  

Is there something missing in my structure of the codes or is my logic in appending the values not right? Your responses would indeed help me in resolving this issue. Thank you very much.

https://stackoverflow.com/questions/66997200/how-to-append-only-one-line-row-for-each-iteration-in-appending-values-to-csv-fi April 08, 2021 at 12:06PM