根据jlist选定的值从数据库中获取项目并存储在数组中

Question

I have a table Users in my database with columns phone no and region . In my GUI, I have a JList from where the user can select one or more regions, and accordingly I need to send out messages to the phone numbers with matching region.

The problem I'm facing is in retrieving the phone numbers from the database. This is my code

        final JList listRegion = new JList(list);
        listRegion.setSelectionMode(ListSelectionModel.MULTIPLE_INTERVAL_SELECTION);
        listRegion.setVisibleRowCount(3);
        JScrollPane scroll = new JScrollPane(listRegion);
        scroll.setBounds(113, 254, 123, 50);    
        frame.getContentPane().add(scroll);

I'm storing the selected list values like this

Object[] areaList = listRegion.getSelectedValues();

Now I need to retrieve all the numbers with their corresponding regions matching the regions in areaList and need to store them in an array. I have tried something like this. But it seems to be wrong.

for( int i=0; i<areaList.length ; i++){
    String sql2 = "select phone_no from users where region = areaList["+i+"]";
    result = statement.executeQuery(sql2);

    while(result.next()){
        String numbers = result.getString(1);
        //System.out.println(numbers);
    }
} 

I am poor with arrays. Hence not able to do it. Please guide me with the correct way of doing this.

Answer 1

You are not able to access the areaList variable from sql. Probably you need something like (not tested):

String sql2 = "select phone_no from users where region in (";
for( int i=0; i<areaList.length ; i++){
    sql2 += "\'"+ areaList[i]+"\'";
    if (i<areaList.length-1)
        sql2+=",";
}
sql+=")";

result = statement.executeQuery(sql2);

while(result.next()){
        String numbers = result.getString(1);
        //System.out.println(numbers);
}

Also note that you should use a PreparedStatement , instead building the sql manually, this way you will be protected by sql injection issues.