Exception in thread “AWT-EventQueue-0” java.lang.ClassCastException: class java.lang.Integer cannot be cast to class java.lang.String

问题

I writing JTable data into CSV file using OpenCSV jar. Everything works fine unless it comes to read data from the table data. Whenever I am choosing the first row it works perfectly. But when I am choosing the more than one row it gives the exception which is mentioned in the title.

Below is the code:

        DefaultTableModel tableModel = (DefaultTableModel) jTable1.getModel();
        int rows = Integer.parseInt((String)jTextField8.getText());
        String fileName = jTextField11.getText()+".csv";
        File file = new File("/Users/startelelogic/Desktop/fileName");
        if (jTable1.isEditing()){
            jTable1.getCellEditor().stopCellEditing();
        }
        try{
            FileWriter outputFile = new FileWriter(fileName);
            CSVWriter writer = new CSVWriter(outputFile);
            //  Adding Header to csv File
            String header[] = {"Sr. No.","CM","Liters"};
            writer.writeNext(header);
            //  Adding data to csv
            System.out.println("Rows \t:"+rows);
            for(int i=0; i<rows; i++){
                String[] data = new String[3];
                for(int j=0; j< tableModel.getColumnCount(); j++){
                    data[j] = (String)tableModel.getValueAt(i, j);
                }
                writer.writeNext(data);
                writer.close();
            }
            JOptionPane.showMessageDialog(null, "Table Data Written successfully!");
        }catch(IOException ex){
            JOptionPane.showMessageDialog(null, "FileWriting error");
            ex.printStackTrace();
        }

回答1:

java.lang.ClassCastException: class java.lang.Integer cannot be cast to class java.lang.String

Well the error message is telling you the problem. You can't make an Integer object be a String object.

data[j] = (String)tableModel.getValueAt(i, j);

The above statement assumes all data in the table is an instance of String.

Instead you can use:

data[j] = tableModel.getValueAt(i, j).toString();

Now you data array will contain the String representation of every object.

来源：https://stackoverflow.com/questions/61403516/exception-in-thread-awt-eventqueue-0-java-lang-classcastexception-class-java

标签

java

swing

jtable

opencsv