java - comparator for LinkedHashMap

Question

i am making a program to read data from excel files and store them in tables. But since I am new to Comparators in Java i have difficulties in making one of them. Here is my issue, I have managed to read all the data from excel files as a string and store them in a table. But my project is to store them in table by ascending IDs. Can someone help me to create a Comparator to compare LinkedHashmaps and store them by their IDs? The data that I have to store is like the below:

ID  Name    Salary         
50  christine   2349000        
43  paulina 1245874        
54  laura   4587894 

The code for parsing the data is the below:

private static LinkedHashMap parseExcelColumnTitles(List sheetData) {

    List list = (List) sheetData.get(0);
    LinkedHashMap < String, Integer > tableFields = new LinkedHashMap(list.size());
    for (int j = 0; j < list.size(); j++) {
        Cell cell = (Cell) list.get(j);
        tableFields.put(cell.getStringCellValue(), cell.getCellType());
    }

    return tableFields;

}

private static LinkedHashMap[] parseExcelColumnData(List sheetData) {

    LinkedHashMap[] tousRows = new LinkedHashMap[sheetData.size() - 1];
    for (int rowCounter = 1; rowCounter < sheetData.size(); rowCounter++) {

        List list = (List) sheetData.get(rowCounter);

        LinkedHashMap < String, Integer > tableFields = new LinkedHashMap(list.size());
        String str;
        String[] tousFields = new String[list.size()];

        int i = 0;

        for (int j = 0; j < list.size(); j++) {
            Cell cell = (Cell) list.get(j);
            if (cell != null) {
                if (cell.getCellType() == Cell.CELL_TYPE_NUMERIC) {
                    tableFields.put(String.valueOf(cell
                        .getNumericCellValue()), cell.getCellType());
                } else if (cell.getCellType() == Cell.CELL_TYPE_STRING) {
                    tableFields.put(cell.getStringCellValue(), cell
                        .getCellType());
                } else if (cell.getCellType() == Cell.CELL_TYPE_BOOLEAN) {
                    tableFields.put(String.valueOf(cell
                        .getBooleanCellValue()), cell.getCellType());
                }
            }

        }
        tousRows[rowCounter - 1] = tableFields;
    }

    return tousRows;

}

Answer 1

you can use TreeMap instead of LinkedHashMap, because you dont want to retain the order of insertion, and for sorting TreeMap is better choice. Read this too Java TreeMap Comparator