Java, looping through result set

Solution 1:

List<String> sids = new ArrayList<String>();
List<String> lids = new ArrayList<String>();

String query = "SELECT rlink_id, COUNT(*)"
             + "FROM dbo.Locate  "
             + "GROUP BY rlink_id ";

Statement stmt = yourconnection.createStatement();
try {
    ResultSet rs4 = stmt.executeQuery(query);

    while (rs4.next()) {
        sids.add(rs4.getString(1));
        lids.add(rs4.getString(2));
    }
} finally {
    stmt.close();
}

String show[] = sids.toArray(sids.size());
String actuate[] = lids.toArray(lids.size());

Solution 2:

Result Set are actually contains multiple rows of data, and use a cursor to point out current position. So in your case, rs4.getString(1) only get you the data in first column of first row. In order to change to next row, you need to call next()

a quick example

while (rs.next()) {
    String sid = rs.getString(1);
    String lid = rs.getString(2);
    // Do whatever you want to do with these 2 values
}

there are many useful method in ResultSet, you should take a look :)

Solution 3:

• The ResultSet should be closed.
• PreparedStatement might protect agains SQL injection.
• The PreparedStatement should be eventually closed.

So the snippet might look like this:

PreparedStatement ps = connection.prepareStatement(sql);
try(ResultSet rs = ps.executeQuery()){
    while(rs.next()) {
        String val = rs.getString(1);
    }
}