actionlistener上未报告的异常java.io.IOException

Question

I am new to java and I am trying to make it to when a button is pushed, it will update the new information that was put in the table. I am getting this error:

unreported exception java.io.IOException; must be caught or declared to be thrown

Here the code I'm having trouble in:

public static void updateAction(){

update.addActionListener(new ActionListener() {


 @Override
 public void actionPerformed(ActionEvent e) {
 BufferedWriter bfw = new BufferedWriter(new FileWriter(tmp));
 for(int i = 0 ; i < table.getColumnCount() ; i++)
 {
 bfw.write(table.getColumnName(i));
 bfw.write("\t");
 }

 for (int i = 0 ; i < table.getRowCount(); i++)
 {
 bfw.newLine();
 for(int j = 0 ; j < table.getColumnCount();j++)
 {
 bfw.write((String)(table.getValueAt(i,j)));
 bfw.write("\t");;
 }


 }
  bfw.close();

 }});     
}

Thanks for any help you can give me.

Answer 1

The methods of BufferedWriter throw an IOException . You must either catch it in your method body or declare your method to throw it.

Since you are using an anonymous implementation of ActionListener , you can't change the signature of actionPerformed . So you must catch the IOException inside of actionPerformed .

Answer 2

You should catch like this

try {
   ....
} catch(IOException e) {

}

or throws IOException at

public void actionPerformed(ActionEvent e) throws IOException