getting specific row values of database table into an arraylist - sql

Question

I am trying to get certain row records from a db_table into an array list. though this has been done many times, mine is a bit more different.
suppose I have a table in my database like this below:
+---------+--------+--------+
| NAME | BILL | CONTACT|
+---------+--------+--------+
| james | 400 | 024669 |
| Mavis | 700 | 025550 |
| john | 650 | 029510 |
| bendo | 340 | 023579 |
+---------+--------+--------+
and I want an array to display records like this:
[james,400,024669]
[Mavis,700, 025550]
[John,650, 029510]
[bendoo,340,023579]
please how do I achieve that. the code I wrote gave me only a last array. and its:
ArrayList<String> inner = null;
try{
String sql="select Name,Score,Contact from members";
pst=conn.prepareStatement(sql);
rs=pst.executeQuery();
ResultSetMetaData rsmd = rs.getMetaData();
int columnsNumber = rsmd.getColumnCount();
while (rs.next()) {
inner = new ArrayList<>();
for(int i=1; i<=columnsNumber; i++){
inner.add(rs.getString(i));
}
}
System.out.println(inner);
}catch(Exception e){
}
but this is the only System.out.PrintIn displayed:
[bendoo,340,023579]
BUILD SUCCESSFUL (total time: 2 minutes 13 seconds)
please how do I get this below as my result:
[james,400,024669]
[Mavis,700, 025550]
[John,650, 029510]
[bendoo,340,023579]

Answer 1

You need to add inner to a global list. Otherwise you lose the row value every time, and keep only the last one.
Your code should be changed to something like:
ArrayList<String> inner = null;
try {
String sql = "select Name, Score, Contact from members";
pst = conn.prepareStatement(sql);
rs = pst.executeQuery();
List<List<String>> allRows = new ArrayList<List<String>>(); // add this!
while (rs.next()) {
inner = new ArrayList<>();
for(int i=1; i<=columnsNumber; i++){
inner.add(rs.getString(i));
}
System.out.println("ROW: "+row); // Add this line.
allRows.add(inner); // add this line!
}
for (List<String> row : allRows) {
System.out.println(row);
}
} catch (SQLException e) {
e.printStackTrace();
}
please this is what I have fully so far..
ArrayList<String> inner = null;
try {
String sql = "select Name,Score, Contact from members";
pst = conn.prepareStatement(sql);
rs = pst.executeQuery();
ResultSetMetaData rsmd = rs.getMetaData();
int columnsNumber = rsmd.getColumnCount();
List<List<String>> allRows = new ArrayList<List<String>>(); // add this!
while (rs.next()) {
inner = new ArrayList<>();
for(int i=1; i<=columnsNumber; i++){
inner.add(rs.getString(i));
}
allRows.add(inner); // add this line!
}
for (List<String> row : allRows) {
System.out.println(row);
}
} catch (SQLException e) {
}
try{
// initialise SMS object.
ZenophSMS sms = new ZenophSMS();
sms.setUser("example#gmail.com");
sms.setPassword("xxxxxxx");
sms.authenticate();
// set message parameters.
sms.setMessage("Hello {$name}, your score is {$score} . please come for you money ");
sms.setSenderId("NICE ONE");
sms.setMessageType(MSGTYPE.TEXT);
// add destinations.
for ( ArrayList<String> recpt : allRows) sms.addRecipient(recpt.get(2), new String[] {recpt.get(0), recpt.get(1)}, false);
// submit the message. Since the total number of destinations is
// less than 400, the submit status of the destinations will be returned.
List<String[]> resp = sms.submit();
// show the status
for (String[] dest : resp)
{ REQSTATUS st = REQSTATUS.fromInt(Integer.parseInt(dest[0]));
if (null != st)
switch (st) {
case SUCCESS:
System.out.println("Submitted: %s"+ dest[1]);
break;
case ERR_INSUFF_CREDIT:
System.out.println("Insufficient Credits: %s"+dest[1]);
break;
default:
System.out.println("Failed: %s"+ dest[1]);
break;
}
}
}
catch (SMSException ex) { System.out.println("Error: " + ex.getMessage()); }
catch (Exception ex) { System.out.println("Error: " + ex.getMessage()); }
this line cant find the array 'allRows'. please what do I do.its giving me an error message that variable cannot be found.
for ( ArrayList<String> recpt : allRows) sms.addRecipient(recpt.get(2),new String[] {recpt.get(0), recpt.get(1)}, false);

Answer 2

Move "inner = new ArrayList<>();" before the "while" statement. You are reinitializing the arraylist for every row.