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Looping try/catch statement

I'm trying to take two random rowid from my database. Everything works but I have a scenario when there is only one rowid. I want to make a loop on my try/catch until there is second number in my database.
What I'm doing wrong? Thank you
public void Kaslaimejo() {
String sql = "SELECT rowid FROM Zaidejai WHERE Pirmas < 4 ORDER BY random() LIMIT 2";
Integer value1 = null, value2 = null;
Integer judesiukas1 = null, judesiukas2 = null;
int a = 0;
int k = 15; // kiek kartu? Reikia infinity padaryti
for (a = 0; a < 3; a++) {
try {
Connection conn = Serveris.connect();
Statement stmt = conn.createStatement();
ResultSet rs = stmt.executeQuery(sql)) {
if (rs.next()) {
value1 = rs.getInt("rowid");
if (rs.next()) {
value2 = rs.getInt("rowid");
PreparedStatement buvo = conn.prepareStatement("UPDATE Zaidejai SET Numeriukas = ? WHERE rowid = ?");
buvo.setInt(1, i);
buvo.setInt(2, value1);
int buvolala = buvo.executeUpdate ();
PreparedStatement buvo2 = conn.prepareStatement("UPDATE Zaidejai SET Numeriukas = ? WHERE rowid = ?");
buvo2.setInt(1, i);
buvo2.setInt(2, value2);
int buvolala2 = buvo2.executeUpdate ();//
i++;
}
System.out.println("Pirmas zaidejas" + value1); // atspausdina 1 random zaideja is duomenu bazes
System.out.println("Antras zaidejas" + value2); // atspausdina 2 random zaideja is duomenu bazes
}
} catch (SQLException e) {
a--;
//System.out.println(e.getMessage());
}
}
}
Right now my program loops two times and then gives me SQLException. How I can loop my program until there is no SQLException?

OK, I've tried to write what I think you're trying to do.
You wait for ever until someone puts at least two entries in the database.
You extract two values, process them, then wait some more.
Some points to watch out:
1. Object comparisons need to be made with .equals() not with ==
2. You might want to provide some way to break out of the infinite loop I've written (while(true)).
3. Careful with null values. They might produce NullPointerException.
4. Try to break up your code into methods. Each large block of code could go into each own method.
public void Kaslaimejo(){
String sql = "SELECT rowid FROM Zaidejai WHERE Pirmas < 4 ORDER BY random() LIMIT 2";
Integer judesiukas1 = null, judesiukas2 = null;
while(true) {
List<Integer> values = new ArrayList<>();
while (values.size() < 2) {
try (Connection conn = Serveris.connect();
Statement stmt = conn.createStatement();
ResultSet rs = stmt.executeQuery(sql)) {
if( rs.next() ){
Integer value = rs.getInt("rowid");
values.add(value);
}
} catch (SQLException e) {
e.printStackTrace();
}
}
try( Connection conn = Serveris.connect()) {
PreparedStatement buvo = conn.prepareStatement("UPDATE Zaidejai SET Numeriukas = ? WHERE rowid = ?");
buvo.setInt(1, i);
buvo.setInt(2, values.get(0));
int buvolala = buvo.executeUpdate ();
PreparedStatement buvo2 = conn.prepareStatement("UPDATE Zaidejai SET Numeriukas = ? WHERE rowid = ?");
buvo2.setInt(1, i);
buvo2.setInt(2, values.get(1));
int buvolala2 = buvo2.executeUpdate ();//
i++;
}catch (SQLException e) {
e.printStackTrace();
}
Connection conn = Serveris.connect();
try {
PreparedStatement pstmt = conn.prepareStatement("SELECT Pirmas FROM Zaidejai WHERE rowid = ?");
PreparedStatement pstmt2 = conn.prepareStatement("SELECT Pirmas FROM Zaidejai WHERE rowid = ?");
pstmt.setInt(1, values.get(0));
pstmt2.setInt(1, values.get(1));
ResultSet myrsv = pstmt.executeQuery();
ResultSet myrsv2 = pstmt2.executeQuery();
{
if (myrsv.next()) {
judesiukas1 = myrsv.getInt("Pirmas");
if (myrsv2.next()) {
judesiukas2 = myrsv2.getInt("Pirmas");
}
}
//System.out.println("Pirmo zaidejo veiksmas" + myrsv.getInt("Pirmas"));
//System.out.println("Antro zaidejo veiksmas" + myrsv2.getInt("Pirmas"));
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
if (judesiukas1.equals(judesiukas2)) // careful here. NullPointerException may happen.
{
try {
PreparedStatement laim = conn.prepareStatement("UPDATE Zaidejai SET Rezultatas = ? WHERE rowid = ?"); // ble ble update reikia naudoti , o ne insert into. Insert kai sukuriame nauja kazka tik
PreparedStatement laim2 = conn.prepareStatement("UPDATE Zaidejai SET Rezultatas = ? WHERE rowid = ?");
laim.setString(1, "Lygiosios");
laim.setInt(2, values.get(0));
laim2.setString(1, "Lygiosios");
laim2.setInt(2, values.get(1));
int irasyk = laim.executeUpdate (); // kodel executeupdate, o ne executequery????
int irasyk2 = laim2.executeUpdate (); // kodel executeupdate, o ne executequery????
{
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
System.out.print("Lygiosios");
} else {
// (1) - Rock
// (2) Scissors
// (3) - Paper
switch (values.get(0)){
case 1:
if (judesiukas2 == 2)
System.out.print("Zaidejas 1 wins!");
else
System.out.print("Zaidejas 2 wins!");
break;
case 2:
if (judesiukas2 == 3)
System.out.print("Zaidejas 1 wins!");
else
System.out.print("Zaidejas 2 wins!");
break;
case 3:
if (judesiukas2 == 1)
System.out.print("Zaidejas 1 wins!");
else
System.out.print("Zaidejas 2 wins!");
break;
}
}
try {
conn.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}

The logic becomes easier if you add the values to a list
var values = new ArrayList<Integer>();
while (values.Count < 2) {
try (Connection conn = Serveris.connect();
Statement stmt = conn.createStatement();
ResultSet rs = stmt.executeQuery(sql))
{
while (values.Count < 2 && rs.next()) {
Integer v = rs.getInt("rowid");
values.Add(v);
}
} catch (SQLException e) {
}
}
//TODO: process the values here
The advantage is, that you can retrieve one value at the first database query and the second at a later one or both in the same round and you don't have to keep track of which one of two variables to use.
(Bear with me with the syntax details, I'm not a Java programmer.)

How i can loop my program until there is no SQLException?
Change this (because, it will only allow to loop two times)
for (a = 0; a < 2; a++) {
to
while(true)
Put everything inside while(true), if exception occurred, then it will come out from the while loop. Something similar :
try
{
while(true)
{
...
...
}
...
}
catch(SQLException e)
{
// do somthing
}

APOSTROPHE issue with java and SQL

I have code, where I have single quote or APOSTROPHE in my search
I have database which is having test table and in name column of value is "my'test"
When running
SELECT * from test WHERE name = 'my''test';
this works fine
If I use the same in a Java program I am not getting any error or any result
But If I give the name with only single quote then it works
SELECT * from test WHERE name = 'my'test';
Could you please help me out to understand.
Java code is
Connection con = null;
PreparedStatement prSt = null;
try {
Class.forName("oracle.jdbc.driver.OracleDriver");
con = DriverManager.
getConnection("jdbc:oracle:thin:#localhost:1521:orcl"
,"user","pwd");
String query = "SELECT * from "
+ "WHERE name = ? ";
prSt = con.prepareStatement(query);
String value = "my'mobile";
char content[] = new char[value.length()];
value.getChars(0, value.length(), content, 0);
StringBuffer result = new StringBuffer(content.length + 50);
for (int i = 0; i < content.length; i++) {
if (content[i] == '\'')
{
result.append("\'");
result.append("\'");
}
else
{
result.append(content[i]);
}
}
prSt.setObject(1, result.toString());
int count = prSt.executeUpdate();
System.out.println("===============> "+count);
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (SQLException e) {
e.printStackTrace();
} finally{
try{
if(prSt != null) prSt.close();
if(con != null) con.close();
} catch(Exception ex){}
}

You don't have to escape anything for the parameter of a PreparedStatement
Just use:
prSt = con.prepareStatement(query);
prSt.setString("my'mobile");
Additionally: if you are using a SELECT statement to retrieve data, you need to use executeQuery() not executeUpdate()
ResultSet rs = prst.executeQuery();
while (rs.next())
{
// process the result here
}
You might want to go through the JDBC tutorial before you continue with your project: http://docs.oracle.com/javase/tutorial/jdbc/index.html

Ignore exception and continue to insert the rest of the data

I have the following codes snippet. I remove further details. I have a for loop with all the data in it. The I run the for loop for (int i = 0; i < list.getLength(); i++). What happens is that the moment any one of the data cause the sql with error say the data has a slash etc then it cause exception and the rest of the for loop cant continue. How can I like skip the one with the exception and continue with rest?
Here is a the codes.
Connection dbconn = null;
Statement stmt1 = null;
Statement stmt2 = null;
try
{
dbconn = DriverManager.getConnection("jdbc:mysql://localhost:3306/test1", "tes1", "te15");
stmt1 = dbconn.createStatement();
stmt2 = dbconn.createStatement();
DateFormat outDf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
Date date = Calendar.getInstance().getTime();
String value = null;
for (int i = 0; i < list.getLength(); i++)
{
String insertCommand = "INSERT INTO command SET .........";
System.out.println("\n SET INSERT :" + insertCommand);
int count = stmt1.executeUpdate(insertCommand);
}
}
catch (SQLException ex)
{
System.out.println("MyError Error SQL Exception : " + ex.toString());
}
catch (Exception rollback)
{
System.out.println("\nRollback :");
rollback.printStackTrace(System.out);
}
catch (Exception e)
{
System.out.println("\n Error here :");
e.printStackTrace(System.out);
}
finally
{
try
{
if (stmt1 != null)
{
stmt1.close();
}
}
catch (SQLException ex)
{
System.out.println("MyError: SQLException has been caught for stmt1 close");
ex.printStackTrace(System.out);
}
try
{
if (stmt2 != null)
{
stmt2.close();
}
}
catch (SQLException ex)
{
System.out.println("MyError: SQLException has been caught for stmt2 close");
ex.printStackTrace(System.out);
}
try
{
if (dbconn != null)
{
dbconn.close();
}
else
{
System.out.println("MyError: dbConn is null in finally close");
}
}
catch (SQLException ex)
{
System.out.println("MyError: SQLException has been caught for dbConn close");
ex.printStackTrace();
}
}

You need to put the try/catch block inside the for, around executeUpdate(insertCommand);

You need to catch the error in the loop too
....
for (int i = 0; i < list.getLength(); i++) {
try {
String insertCommand = "INSERT INTO command SET .........";
System.out.println("\n SET INSERT :" + insertCommand);
int count = stmt1.executeUpdate(insertCommand);
} catch (Exception e) {
// Better catch the real exception
// Handle the exception
}
}
....

SQL executeBatch slow processing

Basically i have to read a csv file and perform some validation.
If duplicate record is found i've to delete the previous record and insert the latest 1.
The file contains about 100k records. I'm not sure what I'm doing wrongly but it's taking way too long to load the data.
public static ArrayList<BootstrapMessage> loadLocation(File file) {
ArrayList<BootstrapMessage> errors = new ArrayList<BootstrapMessage>();
CSVReader reader = null;
Connection conn = null;
Connection conn2 = null;
PreparedStatement pstmt = null;
PreparedStatement ps = null;
try {
conn = ConnectionManager.getConnection();
conn2 = ConnectionManager.getConnection();
conn.setAutoCommit(false);
pstmt = conn.prepareStatement(INSERT_LOCATION);
ps = conn2.prepareStatement("delete from location where `timestamp` = ? AND mac_address = ?");
reader = new CSVReader(new InputStreamReader(new FileInputStream(file), "UTF-8"));
reader.readNext();//header
String[] record = reader.readNext();
int counter = 2;//starting from line 2. Line 1 is header
int validRecords = 0;
while (record != null) {
ArrayList<String> message = null;
//try {
message = ValidatorUtil.validateLocation(record, file.getName(), counter);
if (message != null) {//contains error
errors.add(new BootstrapMessage(file.getName(), counter, message));
} else {//valid record
String key = record[0] + record[1];
if (locations.containsKey(key)) {//duplicate found.
pstmt.executeBatch();
message = new ArrayList<String>();
message.add("duplicate row");
errors.add(new BootstrapMessage(file.getName(), locations.get(key), message));
//delete record from database
ps.setTimestamp(1, Timestamp.valueOf(record[0]));
ps.setString(2, record[1]);
ps.executeUpdate();
//inserting the latest record
pstmt.setTimestamp(1, Timestamp.valueOf(record[0]));
pstmt.setString(2, record[1]);
pstmt.setInt(3, Integer.parseInt(record[2]));
pstmt.addBatch();
if (validRecords % 2000 == 0) {
pstmt.executeBatch();
}
} else {
pstmt.setTimestamp(1, Timestamp.valueOf(record[0]));
pstmt.setString(2, record[1]);
pstmt.setInt(3, Integer.parseInt(record[2]));
pstmt.addBatch();
validRecords++;
if (validRecords % 2000 == 0) {
pstmt.executeBatch();
}
}
}
if (validRecords > 0) {
pstmt.executeBatch();
conn.commit();
}
record = reader.readNext();
counter++;
}
System.out.println("valid location records = " + validRecords);
//numOfValidRecords.put(fileName, validRecords);
if (!errors.isEmpty()) {
return errors;
}
} catch (FileNotFoundException ex) {
Logger.getLogger(LocationDAO.class.getName()).log(Level.SEVERE, null, ex);
} catch (IOException ex) {
Logger.getLogger(LocationDAO.class.getName()).log(Level.SEVERE, null, ex);
} catch (SQLException ex) {
Logger.getLogger(LocationDAO.class.getName()).log(Level.SEVERE, null, ex);
} finally {
if (reader != null) {
try {
reader.close();
} catch (IOException ex) {
Logger.getLogger(LocationDAO.class.getName()).log(Level.SEVERE, null, ex);
}
}
ConnectionManager.close(conn2, ps);
ConnectionManager.close(conn, pstmt);
}
return null;
}

Why don't you use native database loaders to do the job?
Or I would first insert all the records into staging and then do the duplicate removals by using the database tools, either SQL or some database procedure. This way it has to be faster.

Validator not working properly

I have a JSF validator which is used to validate input from form.
When I insert simple string or duplicated string it's working properly. But when I don't enter anything the proper message will be This field cannot be empty!" : " '" + s + "' is not a valid name! but I don't get anything. Can you help me to find the problem into the code logic?
// Validate Datacenter Name
public void validateDatacenterName(FacesContext context, UIComponent component, Object value) throws ValidatorException, SQLException
{
String l;
String s = value.toString().trim();
if (s != null && s.length() > 18)
{
throw new ValidatorException(new FacesMessage(FacesMessage.SEVERITY_ERROR,
" Value is too long! (18 digits max)", null));
}
try
{
// l = Long.parseLong(s);
// if (l > Integer.MAX_VALUE)
// {
// throw new ValidatorException(new FacesMessage(FacesMessage.SEVERITY_ERROR,
// " '" + l + "' is too large!", null));
// }
}
catch (NumberFormatException nfe)
{
l = null;
}
if (s != null)
{
if (ds == null)
{
throw new SQLException("Can't get data source");
}
Connection conn = null;
PreparedStatement ps = null;
ResultSet rs;
int cnt = 0;
try
{
conn = ds.getConnection();
ps = conn.prepareStatement("SELECT count(1) from COMPONENTSTATS where NAME = ?");
ps.setString(1, s);
rs = ps.executeQuery();
while (rs.next())
{
cnt = rs.getInt(1);
}
if (cnt > 0)
{
throw new ValidatorException(new FacesMessage(FacesMessage.SEVERITY_ERROR,
" '" + s + "' is already in use!", null));
}
}
catch (SQLException x)
{
throw new ValidatorException(new FacesMessage(FacesMessage.SEVERITY_ERROR,
" SQL error!", null));
}
finally
{
if (ps != null)
{
ps.close();
}
if (conn != null)
{
conn.close();
}
}
}
else
{
throw new ValidatorException(new FacesMessage(FacesMessage.SEVERITY_ERROR,
s.isEmpty() ? " This field cannot be empty!" : " '" + s + "' is not a valid name!", null));
}
}

that is because you only check if you s is != null.
change if (s != null) to if (s != null && s.lenght() > 0) and try again.
btw your String s can't be null, because you initialize it with
String s = value.toString().trim();
and this would cause a NullPointerException if your value would be null.

Set inputText tag attribute required to true
<h:inputText value="#{backingBean.input}" required="true"
requiredMessage="Input is empty!">