How to Close Statements and Connection in This Method
public static ResultSet getData (String query){
try {
Connection con = ConnectionProvider.connect();
Statement st = con.createStatement();
ResultSet rs = st.executeQuery(query);
return rs;
} catch (Exception e) {
JOptionPane.showMessageDialog(null, e);
System.out.println(e);
return null;
}
You need to close connections in finally block:
try {
...
}
catch {
...
}
finally {
try { st.close(); } catch (Exception e) { /* Ignored */ }
try { con.close(); } catch (Exception e) { /* Ignored */ }
}
In Java 7 and higher you can define all your connections and statements as a part of try block:
try(Connection con = ConnectionProvider.connect();
Statement st = con.createStatement();
ResultSet rs = st.executeQuery(query);
) {
// Statements
}
catch(....){}
One should use try-with-resources to automatically close all.
Then there is the p
public static void processData (String query, Consumer<ResultSet> processor){
try (Connection con = ConnectionProvider.connect();
Statement st = con.createStatement();
ResultSet rs = st.executeQuery(query)) {
processor.accept(rs);
} catch (SQLException e) {
JOptionPane.showMessageDialog(null, e);
System.getLogger(getClass().getName()).log(Level.Error, e);
}
}
processData("SELECT * FROM USERS", rs -> System.out.println(rs.getString("NAME")));
Or
public static <T> List<T> getData (String query, UnaryOperator<ResultSet, T> convert){
try (Connection con = ConnectionProvider.connect();
Statement st = con.createStatement();
ResultSet rs = st.executeQuery(query)) {
List<T> result = new ArrayList<>();
while (rs.next()) {
result.add(convert.apply(rs));
}
return result;
} catch (SQLException e) {
System.getLogger(getClass().getName()).log(Level.Error, e);
throw new IllegalArgumentException("Error in " + query, e);
}
}
Then there is the danger with this function, that users will compose query strings like:
String query = "SELECT * FROM USERS WHERE NAME = '" + name + "'";
Which does not escape the apostrophes like in d'Alembert. It opens the gates to SQL injection, a large security breach. One needs a PreparedStatement, and then can use type-safe parameters.
As with try-with-resources the code already is reduced (no explicit closes), you should drop this kind of function. But almost most programmers make this mistake.
when i wrote function instead of procedure, it compiled.
CREATE OR REPLACE function ilce_gtr
(
p_ilkodu number
)
RETURN VARCHAR2 AS
p_geridonen varchar2(1000);
begin
for rec in(SELECT ADI FROM ILCE WHERE Y_IL=p_ilkodu)
loop
p_geridonen := p_geridonen || '|' || rec.ADI;
end loop;
return p_geridonen;
end;
/
then i created xml via web method, it was successful.
#WebMethod
public String get_ilce (int p_ilkodu) {
Statement stmt=null;
ResultSet rs=null;
Connection conn=null;
String deger=null;
try {
conn= getConnection_test();
String query = "SELECT ILCE_GTR('" + p_ilkodu + "') FROM DUAL";
stmt = conn.createStatement();
rs = stmt.executeQuery(query);
while (rs.next()) {
deger = rs.getString(1);
}
} catch (Exception e) {
return "hata";
} finally {
try {
rs.close();
stmt.close();
conn.close();
} catch (SQLException e) {
return "hata";
}
}
return deger;
}
I want to do the same for inserting to database, can u help me?
#WebMethod
public String add_ilce (int yourInput) {
Statement stmt=null;
ResultSet rs=null;
Connection conn=null;
String deger=null;
try {
conn= getConnection_test();
String query = "INSERT INTO DUAL" + "(yourAttributeName)" +"VALUES (?)";
PreparedStatement preparedStmt = conn.prepareStatement(query);
preparedStmt.setString (1, yourInput);
preparedStmt.execute();
} catch (Exception e) {
return "hata";
} finally {
try {
rs.close();
stmt.close();
conn.close();
} catch (SQLException e) {
return "hata";
}
}
return deger;
}
EDIT: I suggest you to use DAO approach for such scenarios, check here: Data access object (DAO) in Java
EDIT: I edited the post now it must work as it should be, sorry I had some mistakes
web service didnt appear on localhost, there are others.
#WebMethod
public String add_ilce (String p_no, int p_tplm) {
Statement stmt=null;
ResultSet rs=null;
Connection conn=null;
String deger=null;
try {
conn= getConnection_test();
String query = "INSERT INTO DUAL" + "TEMP_TAHAKKUK_AG(ABONENO,TOPLAM)" +"VALUES ('p_no','p_tplm')";
stmt = conn.createStatement();
rs = stmt.executeQuery(query);
while (rs.next()) {
deger = rs.getString(1);
}
} catch (Exception e) {
return "hata";
} finally {
try {
rs.close();
stmt.close();
conn.close();
} catch (SQLException e) {
return "hata";
}
}
return deger;
}
When i run my website it on glassfish server everything works fine but after some time its stop responding and I need to restart glassfish.. I think its cause I not closing the connection. Can someone tell me if this is the problem? if yes how to close it? Here is one of my function.
public Album get_album (String title)
{
try{
//creates a connection to the server
Connection cn = getCon().getConnection();
//prepare my sql string
String sql = "SELECT * FROM albums WHERE Title = ?";
//create prepared statement
PreparedStatement pst = cn.prepareStatement(sql);
//set sql parameters
pst.setString(1, title);
//call the statement and retrieve results
ResultSet rs = pst.executeQuery();
if(rs.next()) {
Album a = new Album();
a.setIdAlbum(rs.getInt("idAlbum"));
a.setTitle(rs.getString("Title"));
a.setYear(rs.getInt("Year"));
a.setIdArtist(rs.getInt("idArtist"));
a.setIdUser(rs.getInt("idUser"));
a.setLike(rs.getInt("Like"));
a.setDislike(rs.getInt("Dislike"));
a.setNeutral(rs.getInt("Neutral"));
a.setViews(rs.getInt("Views"));
return a;
}
}
catch (Exception e) {
String msg = e.getMessage();
}
return null;
}
Assumming the unique error in your application is for not closing the resources after using them, your code should change to:
public Album get_album (String title) {
Connection cn = null;
PreparedStatement pst = null;
ResultSet rs = null;
Album a = null;
try{
//creates a connection to the server
cn = getCon().getConnection();
//prepare my sql string
String sql = "SELECT * FROM albums WHERE Title = ?";
//create prepared statement
pst = cn.prepareStatement(sql);
//set sql parameters
pst.setString(1, title);
//call the statement and retrieve results
rs = pst.executeQuery();
if (rs.next()) {
a = new Album();
a.setIdAlbum(rs.getInt("idAlbum"));
a.setTitle(rs.getString("Title"));
a.setYear(rs.getInt("Year"));
a.setIdArtist(rs.getInt("idArtist"));
a.setIdUser(rs.getInt("idUser"));
a.setLike(rs.getInt("Like"));
a.setDislike(rs.getInt("Dislike"));
a.setNeutral(rs.getInt("Neutral"));
a.setViews(rs.getInt("Views"));
//don't return inside try/catch
//return a;
}
} catch (Exception e) {
String msg = e.getMessage();
//handle your exceptions
//e.g. show them in a logger at least
e.printStacktrace(); //this is not the best way
//this will do it if you have configured a logger for your app
//logger.error("Error when retrieving album.", e);
} finally {
closeResultSet(rs);
closeStatement(pst);
closeConnection(cn);
}
return a;
}
public void closeConnection(Connection con) {
if (con != null) {
try {
con.close();
} catch (SQLException e) {
//handle the exception...
}
}
}
public void closeStatement(Statement st) {
if (st!= null) {
try {
st.close();
} catch (SQLException e) {
//handle the exception...
}
}
}
public void closeResultSet(ResultSet rs) {
if (rs!= null) {
try {
rs.close();
} catch (SQLException e) {
//handle the exception...
}
}
}
I would like to be able to select a data from database and display it using the comboBox.
I have the following code but it does not display the data in the comboBox. I do realize there is codes missing to display the data and my SQL statement is not correct. I am just not sure what I can do any advise is appreciated.
try {
Statement st = db.con.createStatement();
ResultSet rs = st.executeQuery("SELECT Name, Size, Price FROM item WHERE Name=" + comboBox_1.getToolkit());
JOptionPane.showMessageDialog(frame, "displayed");
while (rs.next()) {
String name = rs.getString("Name");
String size = rs.getString("size");
String price = rs.getString("price");
textArea_Name.append(name);
textArea_size.append(size);
textArea_price.append(price);
comboBox_1.addItem(rs.getString("Name"));
comboBox_1.getSelectedItem();
}}
catch (SQLException e ) {
System.out.println("user not added");
e.printStackTrace();
}
}
});
try {
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
Connection conn= DriverManager.getConnection("jdbc:odbc:driverName");
Statement st = conn.createStatement();
ResultSet r=st.executeQuery("select * from tableName");
while (r.next()) {
JComboBox.addItem(r.getString("Key_Coloumn_Name"));
}
conn.close();
} catch (Exception e) {
JOptionPane.showMessageDialog(null,"Failed to Connect to Database","Error Connection", JOptionPane.WARNING_MESSAGE);
System.exit(0);
}
Try this tutorial. It does exactly that.
http://www.roseindia.net/tutorial/java/swing/comboboxwithdatabaseValues.html
try {
Statement stmt = db.con.createStatement();
ResultSet rs = stmt5.executeQuery("select * from tbl_your_table");
while (rs.next()) {
String pat = rs.getString("name");
jComboBox.addItem(pat);
}
} catch (Exception e) {
JOptionPane.showMessageDialog(null, e);
}
con = DriverManager.getConnection("jdbc:mysql://:3306/database","user","password");
stat = con.createStatement();
ResultSet rs = stat.executeQuery("select name from student;");
while(rs.next()){
jComboBox1.addItem(rs.getString("name"));
}
rs.close();
stat.close();
con.close();
comb = new JComboBox();
DefaultComboBoxModel dftm = (DefaultComboBoxModel) comb.getModel();
ArrayList<stock_data> list = userLists();
row = new Object[1];
for (int i = 0; i < list.size(); i++) {
row[0] = list.get(i).get_item();
dftm.addElement(row);
// comb.setModel(dftm);
}
Then create your method and also remember you need a stock_data Class
private ArrayList<stock_data> userLists() {
try {
connection = localhost.dbConnector();
ArrayList<stock_data> usersList = new ArrayList();
try {
String query = "Select * from itemlist";
Statement st = connection.createStatement();
ResultSet rs = st.executeQuery(query);
stock_data users;
while (rs.next()) {
// users = new stock_data(rs.getString("name"));
// usersList.add(users);
comb.addItem(rs.getString("name"));
}
rs.close();
} catch (Exception e) {
JOptionPane.showMessageDialog(null, "blah blah");
e.printStackTrace();
}
return usersList;
} catch (Exception e1) {
e1.printStackTrace();
}
return null;
}
org.apache.commons.dbcp.DelegatingPreparedStatement
is closed
Could i know in which situations this exception will come.
I closed all result sets and prepared statements.
How can i solve this problem.
Code :
public int UpdateMovementLines(List<MaterialRequestIssuanceVO> mlinelist,String projId,String documentno,String user){
int count = 1;
int line = 0;
String uom = null;
String projLocatorId = null;
String projWarehouseId = null;
String warehouseLocatorId = null;
String issuanceId = null;
String movementLineId =null;
String pinstanceId = null;
String sqlQry = null;
String whLocatorId = null;
PreparedStatement ps = null;
PreparedStatement ps1 = null;
PreparedStatement ps2 = null;
PreparedStatement ps3 = null;
PreparedStatement ps4 = null;
PreparedStatement ps5 = null;
ResultSet rs = null;
ResultSet rs1 = null;
ResultSet rs2 = null;
ResultSet rs3 = null;
try{
conn.setAutoCommit(false);
try{
sqlQry="INSERT INTO m_movement (m_movement_id, AD_CLIENT_ID, AD_ORG_ID, CREATED, CREATEDBY, UPDATED, UPDATEDBY," +
"name, movementdate, posted, processing, move_fromto_locator,documentno) VALUES " +
"(?,?,?,NOW(),?,NOW(),?,to_char(now(),'DD-MM-YYYY'),now(),?,?,?,?)";
ps = conn.prepareStatement(sqlQry);
for(MaterialRequestIssuanceVO movementvo:mlinelist){
issuanceId = movementvo.getIssuanceid();
ps.setString(1, issuanceId);
ps.setString(2,movementvo.getClientid());
ps.setString(3,movementvo.getOrgid());
ps.setString(4, movementvo.getCreatedby());
ps.setString(5,movementvo.getUpdatedby());
ps.setString(6,"N");
ps.setString(7,"N");
ps.setString(8,"N");
ps.setString(9, documentno);
count=ps.executeUpdate();
}
}
catch (SQLException e) {
// TODO Auto-generated catch block
log4j.info("Inside DB Line saveMRIssuanceMovementData Exception"+e);
}
finally
{
try
{
ps.close();
log4j.info("Inside Line Finally");
} catch (SQLException e) {
e.printStackTrace();
}
}
ps=conn.prepareStatement("select c_uom_id as uom from m_product where m_product_id = ?");
for(MaterialRequestIssuanceVO movementvo:mlinelist){
line = line +10;
ps.setString(1, movementvo.getMaterialid());
rs = ps.executeQuery();
while(rs.next())
{
uom = rs.getString("uom");
log4j.info("Uom: "+uom);
}
try{
ps2=conn.prepareStatement("select m_locator_id as locatorid from m_locator where m_warehouse_id = ?");
ps2.setString(1, movementvo.getWarehouseId());
rs2 = ps2.executeQuery();
while(rs2.next())
{
warehouseLocatorId = rs2.getString("locatorid");
log4j.info("warehouseLocatorId: "+warehouseLocatorId);
}
}catch(SQLException e){
log4j.info("Warehouse Locator Exception: "+e);
}
finally{
rs2.close();
ps2.close();
}
try{
ps3=conn.prepareStatement("select m_locator_id as locatorid from m_locator where m_warehouse_id=? and value like ?");
ps3.setString(1, movementvo.getWarehouseId());
ps3.setString(2, projId);
rs3 = ps3.executeQuery();
if(rs3.next())
{
projLocatorId = rs3.getString("locatorid");
log4j.info("projLocatorId: "+projLocatorId);
}
else
{
sqlQry="INSERT INTO m_locator (m_locator_id, AD_CLIENT_ID, AD_ORG_ID, CREATED, CREATEDBY, UPDATED, UPDATEDBY," +
"value, m_warehouse_id, priorityno, x,y, z) VALUES " +
"(?,?,?,NOW(),?,NOW(),?,?,?,?,?,?,?)";
ps4 = conn.prepareStatement(sqlQry);
try
{
whLocatorId = SequenceIdData.getUUID();
log4j.info("issueid: "+whLocatorId);
ps4.setString(1, whLocatorId);
log4j.info("Client Id: "+movementvo.getClientid());
ps4.setString(2,movementvo.getClientid());
log4j.info("Orgid: "+movementvo.getOrgid());
ps4.setString(3,movementvo.getOrgid());
ps4.setString(4, movementvo.getCreatedby());
ps4.setString(5,movementvo.getUpdatedby());
ps4.setString(6,projId);
ps4.setString(7,movementvo.getWarehouseId());
ps4.setInt(8,50);
ps4.setString(9,"x");
ps4.setString(10,"y");
ps4.setString(11,"z");
count=ps4.executeUpdate();
if(count == 1)
projLocatorId = whLocatorId;
}
catch(SQLException e)
{
log4j.info("M_Locator Exception: "+e);
}
finally
{
ps4.close();
}
log4j.info("whLocatorId projLocatorId: "+projLocatorId);
}
}catch(SQLException e){
log4j.info("Locator Exception: "+e);
}
finally{
rs3.close();
ps3.close();
}
try{
sqlQry="INSERT INTO m_movementline (m_movementline_id, AD_CLIENT_ID, AD_ORG_ID, CREATED, CREATEDBY, UPDATED, UPDATEDBY," +
"m_movement_id, m_locator_id, m_locatorto_id, m_product_id,line, movementqty,c_uom_id,m_attributesetinstance_id) VALUES " +
"(?,?,?,NOW(),?,NOW(),?,?,?,?,?,?,?,?,?)";
ps1 = conn.prepareStatement(sqlQry);
movementLineId = SequenceIdData.getUUID();
ps1.setString(1, movementLineId);
ps1.setString(2,movementvo.getClientid());
ps1.setString(3,movementvo.getOrgid());
ps1.setString(4, movementvo.getCreatedby());
ps1.setString(5,movementvo.getUpdatedby());
ps1.setString(6,issuanceId);
ps1.setString(7,warehouseLocatorId);
ps1.setString(8,projLocatorId);
ps1.setString(9,movementvo.getMaterialid());
ps1.setInt(10,line);
ps1.setInt(11,Integer.parseInt(movementvo.getIssuedqty()));
ps1.setString(12,uom);
ps1.setString(13,"0");
count=ps1.executeUpdate();
}
catch(SQLException e){
log4j.info("Inside DB MoveLines SQLException"+e.getMessage());
}
finally
{
try
{
ps1.close();
log4j.info("Inside movement Line Finally");
} catch (SQLException e) {
e.printStackTrace();
}
}
}
sqlQry="INSERT INTO ad_pinstance (ad_pinstance_id, AD_CLIENT_ID, AD_ORG_ID, CREATED, CREATEDBY, UPDATED, UPDATEDBY," +
"ad_process_id, record_id, isprocessing, ad_user_id,result) VALUES " +
"(?,?,?,NOW(),?,NOW(),?,?,?,?,?,?)";
ps5 = conn.prepareStatement(sqlQry);
for(MaterialRequestIssuanceVO movementvo:mlinelist){
try{
pinstanceId = SequenceIdData.getUUID();
log4j.info("pinstanceId: "+pinstanceId);
ps5.setString(1, pinstanceId);
log4j.info("Client Id: "+movementvo.getClientid());
ps5.setString(2,movementvo.getClientid());
log4j.info("Orgid: "+movementvo.getOrgid());
ps5.setString(3,movementvo.getOrgid());
ps5.setString(4, movementvo.getCreatedby());
ps5.setString(5,movementvo.getUpdatedby());
ps5.setString(6,"122");
ps5.setString(7,issuanceId);
ps5.setString(8,"N");
ps5.setString(9,user);
ps5.setInt(10, Integer.parseInt("1"));
count=ps5.executeUpdate();
}
catch(SQLException e){
log4j.info("saveMRIssuanceMovementData Line SQLException"+e.getMessage());
}
finally
{
try
{
ps5.close();
log4j.info("Inside movement Line Finally");
} catch (SQLException e) {
e.printStackTrace();
}
}
try{
ps=conn.prepareStatement("select m_movement_post(?)");
ps.setString(1, pinstanceId);
rs = ps.executeQuery();
while(rs.next()){
log4j.info("Result Set: "+rs.getString(1));
}
}catch(SQLException e){
log4j.info("Movement Post Exception: "+e);
}
finally{
ps.close();
}
}
conn.commit();
} catch (Exception e) {
try {
conn.rollback();
count = 0;
} catch (SQLException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
//Above Mensined Exception Catching hear
log4j.info("Inside DB saveMRIssuanceMovementData Line SQLException"+e.getMessage());
}
finally
{
try
{
if(conn != null)
conn.close();
}
catch(SQLException e)
{
}
}
return count;
}
PreparedStatement is closed
You can get this exception when you're trying to (re)use a PreparedStatement while it has been closed. Check the line number of the first line in the stacktrace. It should hint which PreparedStatement it is talking about. Then backtrack its use in the code and fix code accordingly.
Judging the flood of code you've posted, I suspect that it's the ps5 which is been created before a for loop and been closed inside the for loop. Here's an extract of relevance from your code:
ps5 = conn.prepareStatement(sqlQry);
for (MaterialRequestIssuanceVO movementvo : mlinelist) {
try {
ps5.setString(1, string);
ps5.executeUpdate();
} finally {
ps5.close(); // You're closing inside the loop!
}
}
The next iteration in the loop won't be able to reuse the same PreparedStatement anymore. The fix is obvious: close it after completion of the for loop.
try {
ps5 = conn.prepareStatement(sqlQry);
for (MaterialRequestIssuanceVO movementvo : mlinelist) {
ps5.setString(1, string);
ps5.executeUpdate();
}
} finally {
ps5.close();
}
That said, logging all exceptions as Info or doing only e.printStackTrace() and suppressing them and continuing the code flow isn't always a good idea. Log them as Error and then hard-throw thereafter.
} catch (Exception e) {
logger.error("Your message", e);
throw e;
}
Rethrowing isn't needed for exceptions during close, but logging them as Warn is useful.
Last but not least, consider refactoring the exceptionally large method block into separate and sensible methods (tasks) ;)