Develop Reference

Connection to remote Mysql database closing

I made a java app on my local machine which is connecting to a remote MySQL database, when I run on localhost it works OK, but on the remote connection after a few seconds without interaction it is losing the connection and brings
No operation allowed after connection closed.
and
com.mysql.jdbc.exceptions.jdbc4.MySQL.NonTransientConnectionException:No operation allowed after connection closed.
I have tried to remove con.close from my code but still the same.
How do I keep the connection alive until I close the app?
private void jButton18ActionPerformed(java.awt.event.ActionEvent evt) {//GEN-FIRST:event_jButton18ActionPerformed
// TODO add your handling code here:
String stkidreq = txtserchreq.getText();
String pool = lblpool.getText();
String dform = ((JTextField) jdaterfrom.getDateEditor().getUiComponent()).getText();
String dto = ((JTextField) jdaterto.getDateEditor().getUiComponent()).getText();
String rstatus = cmbstatus.getSelectedItem().toString();
String exdate = ((JTextField) jdaterfrom.getDateEditor().getUiComponent()).getText();
((DefaultTableModel) tblreq.getModel()).setRowCount(0);
DefaultTableModel model = (DefaultTableModel) tblreq.getModel();
try {
Class.forName("com.mysql.jdbc.Driver");
java.sql.Connection conn2 = DriverManager.getConnection("jdbc:mysql://so /so n so", "so so", "");
Statement st = conn2.createStatement();
String query = " select r.request_id, r.shareholder_id, s.username, s.shareholder_fname, s.shareholder_lname, s.shareholder_phone, r.request_date, r.request_amount, r.pool, r.notes, r.req_status from requests r, shareholder s, saving_pool p where r.shareholder_id = '" + stkidreq + "' and s.shareholder_id = '" + stkidreq + "' and p.Pool_name = '" + pool + "' and s.pool = '" + pool + "' and s.shareholder_id = r.shareholder_id and (r.request_date between '" + dform + "' and '" + dto + "') and r.req_status = '" + rstatus + "' order by r.request_date asc ";
ResultSet rs = st.executeQuery(query);
while (rs.next()) {
String request_id = rs.getString("request_id");
String shareholder_id = rs.getString("shareholder_id");
String username = rs.getString("username");
String shareholder_fname = rs.getString("shareholder_fname");
String shareholder_lname = rs.getString("shareholder_lname");
String shareholder_phone = rs.getString("shareholder_phone");
String request_date = rs.getString("request_date");
String request_amount = rs.getString("request_amount");
String pool3 = rs.getString("pool");
String notes = rs.getString("request_date");
String req_status = rs.getString("req_status");
model.addRow(new Object[]{request_id, shareholder_id, username, shareholder_fname, shareholder_lname, shareholder_phone, request_date, request_amount, pool3, notes, req_status});
}
rs.close();
st.close();
conn2.close();
} catch (Exception e) {
JOptionPane.showMessageDialog(null, e.getMessage());
}
}

PSQLException index out of bound

I can't figure out why my PreparedStatement is throwing an error.
Here is my function:
public boolean updateMail(int id, String new_mail, boolean showMail) {
String login = "";
String toUpdate = "";
boolean ret = false;
try {
req = cnx.prepareStatement("SELECT login FROM compte WHERE id = ?");
req.setInt(1, id);
ResultSet rs = req.executeQuery();
if (rs.next()) login = rs.getString(1);
} catch (SQLException e) {
e.printStackTrace();
}
if (!getDestinataire(login).equals(new_mail))
toUpdate = ", new_mail=?";
String reqq = "UPDATE compte SET show_mail=?" + toUpdate + " WHERE id=?";
System.out.println("Dest : " + getDestinataire(login) + "\nnew_mail : " + new_mail + "\ntoUpdate : " + toUpdate
+ "\nreqq : " + reqq);
try {
req = cnx.prepareStatement(reqq);
req.setBoolean(1, showMail);
if (!getDestinataire(login).equals(new_mail)) {
req.setString(2, new_mail);
}
req.setInt(2 + (getDestinataire(login).equals(new_mail) ? 0 : 1), id);
req.executeUpdate();
ret = true;
} catch (SQLException e) {
e.printStackTrace();
}
return ret;
}
The getDestinataire() method is working well. The trace I'm printing out looks like this:
Dest : example#example.com new_mail : example2#example2.com toUpdate : ,
new_mail=? reqq : UPDATE compte SET show_mail=?, new_mail=? WHERE id=?
So basically I have 3 columns: show_mail, new_mail and id.
But I have an error at req.setString(2, new_mail);:
org.postgresql.util.PSQLException: L'indice de la colonne est hors limite : 2, nombre de colonnes : 1.
I tried with and without the req.close() because I usually don't use it and it always worked great.
Also, this is the variable definition:
private Connection cnx;
private PreparedStatement req;
I already wrote a hundred database calls. Is this a stupid mistake that I'm too blind to see or is there a lib bug?

Error when trying to insert new data into sql databse in java

I am trying to insert new data in a SQL database using a DAO. I have a boolean method for insert but there is a SQL error or database is missing. Database is not missing because I tested it and it displays everything from the table.
Here is the connection method
public Connection getDBConnection() {
Connection dbConnection = null;
try {
Class.forName("org.sqlite.JDBC");
} catch (ClassNotFoundException e) {
System.out.println(e.getMessage());
}
try {
String dbURL = "jdbc:sqlite:studentdb.sqlite";
dbConnection = DriverManager.getConnection(dbURL);
return dbConnection;
} catch (SQLException e) {
System.out.println(e.getMessage());
}
return dbConnection;
}
And the insert method
public boolean insertStu(Student stu) throws SQLException {
Connection dbConnection = null;
Statement statement = null;
ResultSet resultset = null;
boolean b = false;
try {
String query = "insert into studentdb (Name, Gender, DOB, Address, Postcode, StudentNumber, CourseTitle, StartDate, Bursary, Email) values (\""
+ stu.getName() + "\"," + "\"" + stu.getGender() + "\"," + "\"" + stu.getDob() + "\"," + "\""
+ stu.getAddress() + "\"," + "\"" + stu.getPostcode() + "\"," + "\"" + stu.getStudentNumber()
+ "\"," + "\"" + stu.getCourseTitle() + "\"," + "\"" + stu.getStartDate() + "\"," + "\""
+ stu.getBursary() + "\"," + "\"" + stu.getEmail() + "\")";
dbConnection = getDBConnection();
statement = dbConnection.createStatement();
b = statement.execute(query);
} catch (SQLException s) {
throw new SQLException("Contact Not Added");
} finally {
if (dbConnection != null) {
dbConnection.close();
}
if (statement != null) {
statement.close();
}
if (resultset != null){
resultset.close();
}
}
return b;
}
I have tried the SQL query in different program where the connection method was Statement type and the insert method was still boolean but now the requirement is to use Connection class. Either way it should work but I don't understand way is not working. The Student object has get and set methods for its variables.
Any help would be much appreciated.

Connecting to different schemas using prepared statement

I have the following code running fine with one sql statement selectEmpShowDocs_SQL referring to schema1. In this scenario, I have hard coded the value of empID as 2 as shown in the sql below :
private String selectEmpShowDocs_SQL =
"SELECT " +
"emp_doc " +
"FROM " +
"schema1.emp_info " +
"WHERE " +
"doc_id = ? "+
"AND"+
"empID = 2";
Now, I have another sql statement which is retrieving the emp_id value and instead of hardcoding the value just like I did above for empID, I want to pass the value of emp_id obtained from the following sql statement to the above sql statement. This is the statement which is referring to schema2.
private String selectEmpIDSQL =
"SELECT " +
"emp_id " +
"FROM " +
"schema2.emp_id " +
"WHERE " +
"company_id = 435 "
I am wondering is it possible to connect with two different schemas with one prepared statement? Here someone mentioned that prepared statement is bound to a specific database and in that case if it's not possible, what would be the best approach for me?
Here is the full code that works fine for me using only the SQL query referring to schema1.
public List<EmployeeDocument> getEmployeeDocument(String docId, Integer employeeID) throws DaoException
{
StopWatch stopWatch = new StopWatch();
stopWatch.start();
DataSource ds = null;
Connection conn = null;
PreparedStatement pstmt = null;
ResultSet rs = null;
List<EmployeeDocument> empShowDocs = new ArrayList<EmployeeDocument>();
try {
ds = jdbcTemplate.getDataSource();
conn = ds.getConnection();
pstmt = conn.prepareStatement(selectEmpShowDocs_SQL);
logger.debug("sql query :" + selectEmpShowDocs_SQL);
System.out.println(selectEmpShowDocs_SQL);
pstmt.setString(1, docId);
logger.debug("sql parameters, docId:" + docId);
rs = pstmt.executeQuery();
while(rs.next()) {
EmployeeDocument empShowDocRecord = new EmployeeDocument();
empShowDocRecord.setEmp_Content(rs.getString("emp_doc")));
empShowDocs.add(empShowDocRecord);
}
} catch(Throwable th) {
throw new DaoException(th.getMessage(), th);
} finally {
if (rs != null) {
try {
rs.close();
} catch (SQLException e) {
e.printStackTrace();
}
rs = null;
}
if (pstmt != null) {
try {
pstmt.close();
} catch(SQLException sqe) {
sqe.printStackTrace();
}
pstmt = null;
}
if (conn != null) {
try {
conn.close();
} catch (SQLException sqle) {
sqle.printStackTrace();
}
conn = null;
}
if (ds != null) {
ds = null;
}
}
return empShowDocs;
}
private String selectEmpShowDocs_SQL =
"SELECT " +
"emp_doc " +
"FROM " +
"schema1.emp_info " +
"WHERE " +
"doc_id = ? "+
"AND"+
"empID = 2";
private String selectEmpIDSQL =
"SELECT " +
"emp_id " +
"FROM " +
"schema2.emp_id " +
"WHERE " +
"company_id = 435 "

Getting SQL error 1078 Before start of result set in Java program [duplicate]

This question already has answers here:
ResultSet exception - before start of result set
(6 answers)
Closed 5 years ago.
I have a Java method that is supposed to get column values from one MySQL row and create a string with the values. When run, it generates a SQL error 1078 "Before start of result set."
Here is the the class in which the error is occuring (Problem is in listPosesInSection method:
/** Class used to access the database */
import java.sql.*;
import java.util.ArrayList;
import javax.swing.JOptionPane;
public class YogaDatabaseAccess {
String dbUrl = "jdbc:mysql://localhost/yoga";
private Connection connection;
private ResultSet rset;
private ResultSetMetaData rsMetaData;
private Statement statement;
private PreparedStatement pStatementAll = null;
private PreparedStatement pStatementPartial = null;
// Strings for queries and updates
String strListPosesNotPrimary;
String strInsertNewClass;
String strInsertNewSection;
String strInsertNewPose;
String strUpdateClass;
String strUpdateSection;
String strUpdatePose;
String strArrangePoseOrder;
private String[] poseArray;
// Constructor
YogaDatabaseAccess() {
connectToDatabase();
}
// Method that connects to database
private void connectToDatabase() {
try {
connection = DriverManager.getConnection(dbUrl, "Kyle", "Kullerstrand#2");
System.out.println("Database connected");
}
catch(SQLException e) {
System.out.println(e.getMessage());
}
}
// Query that returns lists to be used with combo boxes
public String listForBoxes(String listName) {
// List to be returned
String strList = "";
// Determine name of the database table for this list
String listTableName;
if (listName == "pose")
listTableName = listName + "s";
else if (listName == "class")
listTableName = listName + "es";
else
listTableName = listName;
// Determine the database column name for this list
String listColumnName = listName + "_name";
// Run the query
try {
statement = connection.createStatement();
rset = statement.executeQuery("SELECT DISTINCT " + listColumnName + " FROM " + listTableName +
" ORDER BY " + listColumnName);
while (rset.next()){
strList = strList + rset.getString(listColumnName) + ", ";
}
} catch (SQLException e) {
e.printStackTrace();
}
return strList;
}
// Query that returns list of primary poses for a section
public String listPrimaryPoses(String sectionName) {
// List to be returned
String strList = "";
// Run the query
try {
statement = connection.createStatement();
rset = statement.executeQuery("SELECT DISTINCT pose_name FROM poses WHERE primarily_suitable_for = '" + sectionName +
"' OR primarily_suitable_for = 'Anything' ORDER BY pose_name");
while (rset.next()){
strList = strList + rset.getString("pose_name") + ", ";
}
} catch (SQLException e) {
e.printStackTrace();
}
return strList;
}
// Query that returns list of secondary poses for a section
public String listSecondaryPoses(String sectionName) {
// List to be returned
String strList = "";
// Run the query
try {
statement = connection.createStatement();
rset = statement.executeQuery("SELECT DISTINCT pose_name FROM poses WHERE sometimes_suitable_for = '" + sectionName + "' ORDER BY pose_name");
while (rset.next()){
strList = strList + rset.getString("pose_name") + ", ";
}
} catch (SQLException e) {
e.printStackTrace();
}
return strList;
}
// Query that returns the poses within a specific section
public String listPosesInSection(String tableName, String sectionName) {
String strList;
StringBuilder strBuilderList = new StringBuilder("");
// Run the query
try {
statement = connection.createStatement();
// Query will collect all columns from one specific row
rset = statement.executeQuery("SELECT * FROM " + tableName + " WHERE " + tableName + "_name = '" + sectionName + "'");
while (rset.next()) {
for (int i = 2; i <= countColumnsInTable(tableName); i++) // First value (0) is always null, skip section name (1)
if (rset.getString(i) != null) // If column has a value
strBuilderList.append(rset.getString(i) + "\n");
}
} catch (SQLException e) {
e.printStackTrace();
}
strList = strBuilderList.toString();
return strList.replaceAll(", $",""); // Strips off the trailing comma
}
// Insert statement that inserts a new class into the classes table
public void insertNewClass(String className) {
/** String insert = "INSERT INTO poses (pose_name, primarily_suitable_for, sometimes_suitable_for) values(?, ?, ?)";
System.out.println("About to create the prepared statement");
// Run the insert
try {
pStatement = connection.prepareStatement(insert);
// statement.execute("INSERT IGNORE INTO poses VALUES ('" + poseName + "', '" + suitableFor + "', '" + suitableForSometimes + "')");
pStatement.setString(1, poseName);
pStatement.setString(2, suitableFor);
pStatement.setString(3, suitableForSometimes);
System.out.println("Created the prepared statement");
// execute query, and return number of rows created
pStatement.executeUpdate();
} catch (SQLException e) {
e.printStackTrace();
} */
}
// Insert statement that inserts a new pose into poses table
public void insertNewPose(String poseName, String suitableFor, String suitableForSometimes) {
String insertAll = "INSERT INTO poses (pose_name, primarily_suitable_for, sometimes_suitable_for) values(?, ?, ?)";
String insertPartial = "INSERT INTO poses (pose_name, primarily_suitable_for) values(?, ?)";
// Run the insert
try {
if (suitableForSometimes == "NULL") { // Insert statement contains a null value for sometimes suitable column
pStatementPartial = connection.prepareStatement(insertPartial);
pStatementPartial.setString(1, poseName);
pStatementPartial.setString(2, suitableFor);
pStatementPartial.executeUpdate();
} else { // Insert statement contains values for all three columns
pStatementAll = connection.prepareStatement(insertAll);
pStatementAll.setString(1, poseName);
pStatementAll.setString(2, suitableFor);
pStatementAll.setString(3, suitableForSometimes);
pStatementAll.executeUpdate();
}
} catch (SQLException e) {
System.err.println("SQLException: " + e.getMessage() + ":" + e.getSQLState());
JOptionPane.showMessageDialog(null, "This pose already exists.");
} finally {
SQLWarning w;
try {
for (w = connection.getWarnings(); w != null; w = w.getNextWarning())
System.err.println("WARNING: " + w.getMessage() + ":" + w.getSQLState());
} catch (SQLException e) {
e.printStackTrace();
JOptionPane.showMessageDialog(null, "An unknown error in the yoga design program has occurred.");
}
}
}
// Insert statement that inserts a new section into warmup, work or restore sections
public void insertNewSection(String sectionType, String sectionName, ArrayList<String> poses) {
System.out.println("insertNewSection method was called");
int maxColumns = countColumnsInTable(sectionType);
poseArray = new String[poses.size()];
poseArray = poses.toArray(poseArray);
if (poseArray.length == 0)
JOptionPane.showMessageDialog(null, "There are no poses in this section. Please add poses.");
// Create a list of columns of the table for the INSERT statement
StringBuilder columns = new StringBuilder(sectionType + "_name");
for (int c = 1; c < maxColumns; c++)
columns.append(", pose_" + c);
// Create a string list of poses, separated by commas, from the array
StringBuilder values = new StringBuilder();
values.append("'" + poseArray[0] + "'");
for (int v = 1; v < poseArray.length - 1; v++)
values.append(", '" + poseArray[v] + "'");
// make sure query uses correct number of columns by padding the query with NULL
for (int i = poseArray.length; i < maxColumns; i++)
values.append(", NULL");
String posesToAddToSection = values.toString();
// The string containing the entire insert statement
String insert = "INSERT INTO " + sectionType + " (" + columns + ") VALUES ('" + sectionName + "', " + posesToAddToSection + ")";
// Run the insert
try {
statement = connection.createStatement();
statement.executeUpdate(insert);
} catch (SQLException e) {
System.err.println("SQLException: " + e.getMessage() + ":" + e.getSQLState());
JOptionPane.showMessageDialog(null, "An error in the yoga design program has occurred. SQLException: " +
e.getMessage() + ":" + e.getSQLState());
} finally {
SQLWarning w;
try {
for (w = connection.getWarnings(); w != null; w = w.getNextWarning())
System.err.println("WARNING: " + w.getMessage() + ":" + w.getSQLState());
} catch (SQLException e) {
e.printStackTrace();
JOptionPane.showMessageDialog(null, "An unknown error in the yoga design program has occurred.");
}
}
}
// Statement that deletes rows from tables
public void deleteRow(String tableName, String columnName, String rowName) {
String delete = "DELETE FROM " + tableName + " WHERE " + columnName + " = '" + rowName + "'";
// Run the insert
try {
statement = connection.createStatement();
statement.executeUpdate(delete);
System.out.println("Delete statement was run on Java's end.");
} catch (SQLException e) {
System.err.println("SQLException: " + e.getMessage() + ":" + e.getSQLState());
JOptionPane.showMessageDialog(null, "Sorry, something went wrong: SQLException: " +
e.getMessage() + ":" + e.getSQLState());
} finally {
SQLWarning w;
try {
for (w = connection.getWarnings(); w != null; w = w.getNextWarning())
System.err.println("WARNING: " + w.getMessage() + ":" + w.getSQLState());
} catch (SQLException e) {
e.printStackTrace();
}
}
}
// Method for getting the number of columns in a table using metadata
public int countColumnsInTable(String sectionType) {
int count = 16;
try {
// System.out.println(sectionType);
statement = connection.createStatement();
rset = statement.executeQuery("SELECT * FROM " + sectionType);
rsMetaData = rset.getMetaData();
count = rsMetaData.getColumnCount();
// System.out.println("Column count is " + count);
} catch (SQLException e) {
e.printStackTrace();
}
return count;
}
// Close the database and release resources
public void closeDatabase() {
try {
connection.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
}
And here is the beginning of the error list:
java.sql.SQLException: Before start of result set
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1078)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:989)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:975)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:920)
at com.mysql.jdbc.ResultSetImpl.checkRowPos(ResultSetImpl.java:855)
at com.mysql.jdbc.ResultSetImpl.getStringInternal(ResultSetImpl.java:5773)
at com.mysql.jdbc.ResultSetImpl.getString(ResultSetImpl.java:5693)
at YogaDatabaseAccess.listPosesInSection(YogaDatabaseAccess.java:125)
at YogaSectionDesigner$5.actionPerformed(YogaSectionDesigner.java:229)

May be you can check this out:
ResultSet exception - before start of result set
Had the same Problem. Solved it that way.