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Open CSV Performance to write data

I came through a link: https://github.com/hyee/OpenCSV which drastically improves the writing time of the JDBC ResultSet to CSV due to setAsyncMode, RESULT_FETCH_SIZE
//Extract ResultSet to CSV file, auto-compress if the fileName extension is ".zip" or ".gz"
//Returns number of records extracted
public int ResultSet2CSV(final ResultSet rs, final String fileName, final String header, final boolean aync) throws Exception {
try (CSVWriter writer = new CSVWriter(fileName)) {
//Define fetch size(default as 30000 rows), higher to be faster performance but takes more memory
ResultSetHelperService.RESULT_FETCH_SIZE=10000;
//Define MAX extract rows, -1 means unlimited.
ResultSetHelperService.MAX_FETCH_ROWS=20000;
writer.setAsyncMode(aync);
int result = writer.writeAll(rs, true);
return result - 1;
}
}
But the problem is I don't know how I can merge above into my requirement. As the link has many other classes involved which I am not sure what they do and if I even need it for my requirement. Still, I tried but it fails to compile whenever I enable 2 commented line code. Below is my code.
Any help on how I can achieve this will be greatly appreciated.
package test;
import java.io.BufferedWriter;
import java.io.FileWriter;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;
import java.util.Date;
import com.opencsv.CSVWriter;
import com.opencsv.ResultSetHelperService;
public class OpenCSVTest1
{
static Connection con =null;
static Statement stmt = null;
static ResultSet rs = null;
public static void main(String args[]) throws Exception
{
connection ();
retrieveData(con);
}
private static void connection() throws Exception
{
try
{
Class.forName("<jdbcdriver>");
con = DriverManager.getConnection("jdbc:","<username>","<pass>");
System.out.println("Connection successful");
}
catch (Exception e)
{
System.out.println("Exception while establishing sql connection");
throw e;
}
}
private static void retrieveData(Connection con) throws Exception
{
try
{
stmt=con.createStatement();
stmt = con.createStatement(ResultSet.TYPE_FORWARD_ONLY, ResultSet.CONCUR_READ_ONLY);
String query = "SELECT * FROM dbo.tablename";
rs=stmt.executeQuery(query);
CSVWriter writer = new CSVWriter(new BufferedWriter(new FileWriter("C:\\Data\\File1.csv")));
ResultSetHelperService service = new ResultSetHelperService();
/*** ResultSetHelperService.RESULT_FETCH_SIZE=10000; ***/ // to add
service.setDateTimeFormat("yyyy-MM-dd HH:mm:ss.SSS");
System.out.println("**** Started writing Data to CSV **** " + new Date());
writer.setResultService(service);
/*** writer.setAsyncMode(aync); ***/ // to add
int lines = writer.writeAll(rs, true, true, false);
writer.flush();
writer.close();
System.out.println("** OpenCSV -Completed writing the resultSet at " + new Date() + " Number of lines written to the file " + lines);
}
catch (Exception e)
{
System.out.println("Exception while retrieving data" );
e.printStackTrace();
throw e;
}
finally
{
rs.close();
stmt.close();
con.close();
}
}
}
UPDATE
I have updated my code. Right now code is writing complete resultset in CSV at once using writeAll method which is resulting in time consumption.
Now what I want to do is write resultset to CSV in batches as resultset's first column will always have dynamically generated via SELECT query Auto Increment column (Sqno) with values as (1,2,3..) So not sure how I can read result sets first column and split it accoridngly to write in CSV. may be HashMap might help, so I have also added resultset-tohashmap conversion code if required.
import com.opencsv.CSVWriter;
import com.opencsv.ResultSetHelperService;
import java.io.BufferedWriter;
import java.io.FileWriter;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.Date;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
public class OpenCSVTest1
{
static int fetchlimit_src = 100;
static Connection con =null;
static Statement stmt = null;
static ResultSet rs = null;
static String filename = "C:\\Data\\filename.csv";
static CSVWriter writer;
public static void main(String args[])
{
try
{
connection();
retrieveData(con);
}
catch(Exception e)
{
System.out.println(e);
}
}
private static void connection() throws Exception
{
try
{
Class.forName("<jdbcdriver>");
con = DriverManager.getConnection("jdbc:","<username>","<pass>");
System.out.println("Connection successful");
}
catch (Exception e)
{
System.out.println("Exception while establishing sql connection");
throw e;
}
}
private static void retrieveData(Connection con) throws Exception
{
try
{
stmt=con.createStatement();
String query = "SELECT ROWNUM AS Sqno, * FROM dbo.tablename "; // Oracle
// String query = "SELECT ROW_NUMBER() OVER(ORDER BY Id ASC) AS Sqno, * FROM dbo.tablename "; // SQLServer
System.out.println(query);
stmt = con.createStatement(ResultSet.TYPE_FORWARD_ONLY, ResultSet.CONCUR_READ_ONLY);
stmt.setFetchSize(fetchlimit_src);
System.out.println("**** Started querying src **** " + new Date());
rs=stmt.executeQuery(query);
System.out.println("**** Completing querying src **** " + new Date());
// resultset_List(rs); // If required store resultset(rs) to HashMap
writetoCSV(rs,filename);
/** How to write resultset to CSV in batches instead of writing all at once to speed up write performance ?
* Hint: resultset first column is Autoincrement [Sqno] (1,2,3...) which might help to split result in batches.
*
**/
}
catch (Exception e)
{
System.out.println("Exception while retrieving data" );
e.printStackTrace();
throw e;
}
finally
{
rs.close();
stmt.close();
con.close();
}
}
private static List<Map<String, Object>> resultset_List(ResultSet rs) throws SQLException
{
ResultSetMetaData md = rs.getMetaData();
int columns = md.getColumnCount();
List<Map<String, Object>> rows = new ArrayList<Map<String, Object>>();
while (rs.next())
{
Map<String, Object> row = new HashMap<String, Object>(columns);
for(int i = 1; i <= columns; ++i)
{
row.put(md.getColumnName(i), rs.getObject(i));
}
rows.add(row);
}
// System.out.println(rows.toString());
return rows;
}
private static void writetoCSV(ResultSet rs, String filename) throws Exception
{
try
{
writer = new CSVWriter(new BufferedWriter(new FileWriter(filename)));
ResultSetHelperService service = new ResultSetHelperService();
service.setDateTimeFormat("yyyy-MM-dd HH:mm:ss.SSS");
long batchlimit = 1000;
long Sqno = 1;
ResultSetMetaData rsmd = rs.getMetaData();
String columnname = rsmd.getColumnLabel(1); // To retrieve columns with labels (for example SELECT ROWNUM AS Sqno)
System.out.println("**** Started writing Data to CSV **** " + new Date());
writer.setResultService(service);
int lines = writer.writeAll(rs, true, true, false);
System.out.println("** OpenCSV -Completed writing the resultSet at " + new Date() + " Number of lines written to the file " + lines);
}
catch (Exception e)
{
System.out.println("Exception while writing data" );
e.printStackTrace();
throw e;
}
finally
{
writer.flush();
writer.close();
}
}
}

You should be able to use the OpenCSV sample, pretty much exactly as it is provided in the documentation. So, there should be no need for you to write any of your own batching logic.
I was able to write a 6 million record result set to a CSV file in about 10 seconds. To be clear -that was just the file-write time, not the DB data-fetch time - but I think that should be fast enough for your needs.
Here is your code, with adaptations for using OpenCSV based on its documented approach... But please see the warning at the end of my notes!
import com.opencsv.CSVWriter;
import com.opencsv.ResultSetHelperService;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;
import java.util.Date;
import java.text.SimpleDateFormat;
public class OpenCSVDemo {
static int fetchlimit_src = 100;
static Connection con = null;
static Statement stmt = null;
static ResultSet rs = null;
static String filename = "C:\\Data\\filename.csv";
public static void main(String args[]) {
try {
connection();
retrieveData(con);
} catch (Exception e) {
System.out.println(e);
}
}
private static void connection() throws Exception {
try {
final String jdbcDriver = "YOURS GOES HERE";
final String dbUrl = "YOURS GOES HERE";
final String user = "YOURS GOES HERE";
final String pass = "YOURS GOES HERE";
Class.forName(jdbcDriver);
con = DriverManager.getConnection(dbUrl, user, pass);
System.out.println("Connection successful");
} catch (Exception e) {
System.out.println("Exception while establishing sql connection");
throw e;
}
}
private static void retrieveData(Connection con) throws Exception {
try {
stmt = con.createStatement();
String query = "select title_id, primary_title from imdb.title";
System.out.println(query);
stmt = con.createStatement(ResultSet.TYPE_FORWARD_ONLY, ResultSet.CONCUR_READ_ONLY);
stmt.setFetchSize(fetchlimit_src);
System.out.println("**** Started querying src **** " + new Date());
rs = stmt.executeQuery(query);
System.out.println("**** Completing querying src **** " + new Date());
// resultset_List(rs); // If required store resultset(rs) to HashMap
System.out.println();
String timeStamp = new SimpleDateFormat("yyyy.MM.dd.HH.mm.ss").format(new Date());
System.out.println("Started writing CSV: " + timeStamp);
writeToCsv(rs, filename, null, Boolean.FALSE);
timeStamp = new SimpleDateFormat("yyyy.MM.dd.HH.mm.ss").format(new Date());
System.out.println("Finished writing CSV: " + timeStamp);
System.out.println();
} catch (Exception e) {
System.out.println("Exception while retrieving data");
e.printStackTrace();
throw e;
} finally {
rs.close();
stmt.close();
con.close();
}
}
public static int writeToCsv(final ResultSet rs, final String fileName,
final String header, final boolean aync) throws Exception {
try (CSVWriter writer = new CSVWriter(fileName)) {
//Define fetch size(default as 30000 rows), higher to be faster performance but takes more memory
ResultSetHelperService.RESULT_FETCH_SIZE = 1000;
//Define MAX extract rows, -1 means unlimited.
ResultSetHelperService.MAX_FETCH_ROWS = 2000;
writer.setAsyncMode(aync);
int result = writer.writeAll(rs, true);
return result - 1;
}
}
}
Points to note:
1) I used "async" set to false:
writeToCsv(rs, filename, null, Boolean.FALSE);
You may want to experiment with this and the other settings to see if they make any significant difference for you.
2) Regarding your comment "the link has many other classes involved": The OpenCSV library's entire JAR file needs to be included in your project, as does the related disruptor JAR:
opencsv.jar
disruptor-3.3.6.jar
To get the JAR files, go to the GitHub page, click on the green button, select the zip download, unzip the zip file, and look in the "OpenCSV-master\release" folder.
Add these two JARs to your project in the usual way (depends on how you build your project).
3) WARNING: This code runs OK when you use Oracle's Java 8 JDK/JRE. If you try to use OpenJDK (e.g. for Java 13 or similar) it will not run. This is because of some changes behind the scenes to hidden classes. If you are interested, there are more details here.
If you need to use an OpenJDK version of Java, you may therefore have better luck with the library on which this CSV library is based: see here.

Java - XLSX parse & database export

I have an excel that filled about 50k-60k rows.
I have to make that excel content uploaded into MySQL, usually I use the apache poi to read and upload it into MySQL, but this file cannot be read using apache poi cause the file was to LARGE.
Can anybody guide me how to do that? Here is my sample code to upload the content into MySQL using apache poi (it works for some little xlsx files that contains 1000-2000 rows)
public static void uploadCrossSellCorpCard(FileItem file, String dbtable) {
System.out.println("UploadUtil Running" + file.getFileName().toString());
try {
for(int i = 0; i<=sheetx.getLastRowNum(); i++){
row = sheetx.getRow(i);
try{
int oc = (int) row.getCell(0).getNumericCellValue();
if((String.valueOf(oc).matches("[A-Za-z0-9]{3}"))){
String rm_name = row.getCell(1).getStringCellValue();
String company = row.getCell(2).getStringCellValue();
String product = row.getCell(3).getStringCellValue();
String detail = row.getCell(4).getStringCellValue();
String type = row.getCell(5).getStringCellValue();
String sql = "INSERT INTO " + dbtable + " VALUES('"
+ oc + "','" + rm_name + "','" + company + "','"
+ product + "','" + detail + "','" + type + "')";
save(sql);
System.out.println("Import rows " + i);
}
} catch (IllegalStateException e) {
e.printStackTrace();
} catch (NullPointerException e) {
System.out.println(e);
}
}
System.out.println("Success import xlsx to mysql table");
} catch (NullPointerException e){
System.out.println(e);
System.out.println("Select the file first before uploading");
}
}
Note: I use hibernate method for handle upload schema.. "save(sql)" is calling my hibernate method

You can try using Apache POI SAX - read the section --> XSSF and SAX (Event API) on https://poi.apache.org/spreadsheet/how-to.html
You can read entire excel with 60k rows or even 100k rows just like reading an xml file. only thing you need to take care is empty cell since xml tag for empty cell will just skip the cell it but you may like to update null value in db table for the cell representing empty value.
Solution --> you can read each row and fire insert statement in a loop. and keep watch on empty cell by monitoring cell address if gap occurs then check respective column name and accordingly update your insert statement with null value.
I hope this helps you. below sample code read excel and store it in ArrayList of ArrayList for tabular representation. I am printing message in console - "new row begins" before start reading and printing row. and cell number of each value before printing cell value itself.
I have not taken care of cell gaps for empty cell but that you can code it based on finding cell gap since in my case I don't have empty cell.
look for cell address in the console that helps you in spotting any gap and handling it as you wish.
Run this code and works fine for me. don't forget to add xmlbeans-2.3.0.jar
other then jars required by import statements.
import java.io.InputStream;
import java.util.ArrayList;
import org.apache.commons.lang3.time.DurationFormatUtils;
import org.apache.commons.lang3.time.StopWatch;
import org.apache.poi.xssf.eventusermodel.XSSFReader;
import org.apache.poi.xssf.model.SharedStringsTable;
import org.apache.poi.xssf.usermodel.XSSFRichTextString;
import org.apache.poi.openxml4j.opc.OPCPackage;
import org.xml.sax.Attributes;
import org.xml.sax.ContentHandler;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
import org.xml.sax.XMLReader;
import org.xml.sax.helpers.DefaultHandler;
import org.xml.sax.helpers.XMLReaderFactory;
public class ExcelToStringArray implements Cloneable {
public static ArrayList<ArrayList<StringBuilder>> stringArrayToReturn = new ArrayList<ArrayList<StringBuilder>>();
public static ArrayList<StringBuilder> retainedString;
public static Integer lineCounter = 0;
public ArrayList<ArrayList<StringBuilder>> GetSheetInStringArray(String PathtoFilename, String rId)
throws Exception {
ExcelToStringArray myParser = new ExcelToStringArray();
myParser.processOneSheet(PathtoFilename, rId);
return stringArrayToReturn;
}
public void processOneSheet(String PathtoFilename, String rId) throws Exception {
OPCPackage pkg = OPCPackage.open(PathtoFilename);
XSSFReader r = new XSSFReader(pkg);
SharedStringsTable sst = r.getSharedStringsTable();
XMLReader parser = fetchSheetParser(sst);
InputStream sheet = r.getSheet(rId);
InputSource sheetSource = new InputSource(sheet);
parser.parse(sheetSource);
sheet.close();
}
public XMLReader fetchSheetParser(SharedStringsTable sst) throws SAXException {
XMLReader parser = XMLReaderFactory.createXMLReader("org.apache.xerces.parsers.SAXParser");
ContentHandler handler = new SheetHandler(sst);
parser.setContentHandler(handler);
return parser;
}
private class SheetHandler extends DefaultHandler {
private SharedStringsTable sst;
private String lastContents;
private boolean nextIsString;
private SheetHandler(SharedStringsTable sst) {
this.sst = sst;
}
public void startElement(String uri, String localName, String name, Attributes attributes) throws SAXException {
if (name.equals("row")) {
retainedString = new ArrayList<StringBuilder>();
if (retainedString.isEmpty()) {
stringArrayToReturn.add(retainedString);
retainedString.clear();
}
System.out.println("New row begins");
retainedString.add(new StringBuilder(lineCounter.toString()));
lineCounter++;
}
// c => cell
if (name.equals("c")) {
// Print the cell reference
System.out.print(attributes.getValue("r") + " - ");
// System.out.print(attributes.getValue("r") + " - ");
// Figure out if the value is an index in the SST
String cellType = attributes.getValue("t");
if (cellType != null && cellType.equals("s")) {
nextIsString = true;
} else {
nextIsString = false;
}
}
// Clear contents cache
lastContents = "";
}
public void endElement(String uri, String localName, String name) throws SAXException {
// Process the last contents as required.
// Do now, as characters() may be called more than once
if (nextIsString) {
int idx = Integer.parseInt(lastContents);
lastContents = new XSSFRichTextString(sst.getEntryAt(idx)).toString();
nextIsString = false;
}
// v => contents of a cell
// Output after we've seen the string contents
if (name.equals("v")) {
System.out.println(lastContents);
// value of cell what it string or number
retainedString.add(new StringBuilder(lastContents));
}
}
public void characters(char[] ch, int start, int length) throws SAXException {
lastContents += new String(ch, start, length);
}
}
public static void main(String[] args) throws Exception {
StopWatch watch = new StopWatch();
watch.start();
ExcelToStringArray generate = new ExcelToStringArray();
// rID1 is first sheet in my workbook for rId2 for second sheet and so
// on.
generate.GetSheetInStringArray("D:\\Users\\NIA\\Desktop\\0000_MasterTestSuite.xlsx", "rId10");
watch.stop();
System.out.println(DurationFormatUtils.formatDurationWords(watch.getTime(), true, true));
System.out.println("done");
System.out.println(generate.stringArrayToReturn);
}
}

MySQLConnection - Error on authenticateUser of "Multiple markers at this line"

I am trying to create my first MySQLConnection in Eclipse and am getting an error on authenticateUser of "Multiple markers at this line
- The return type is incompatible with
DBConnection.authenticateUser(String, String)"
I understand this means "that there is more than one error ... but I can't solve the issue...".
I am using http://altair.cs.oswego.edu/~tenberge/tenbergen.org/misc/DB-Access-in-GWT-The-Missing-Tutorial.pdf as my guide.
This is my code:
AwardTracker.gwt.xml
<module>
<inherits name="com.google.gwt.user.User"/>
<inherits name="com.google.gwt.user.theme.standard.Standard"/>
<entry-point class="org.AwardTracker.client.AwardTracker"/>
<!-- servelet context - path is arbitrary, but must match up with the rpc init inside java class -->
<!-- Tomcat will listen for this from the server and waits for rpc request in this context -->
<servelet class="org.AwardTracker.server.MySQLConnection"
path="/MySQLConnection" />
<inherits name="com.google.gwt.user.theme.standard.Standard"/>
<inherits name="com.google.gwt.user.theme.chrome.Chrome"/>
<inherits name="com.google.gwt.user.theme.dark.Dark"/>
User.java
package org.AwardTracker.client;
import com.google.gwt.user.client.rpc.IsSerializable;
public class User implements IsSerializable {
#SuppressWarnings("unused")
private String username;
#SuppressWarnings("unused")
private String password;
#SuppressWarnings("unused")
private User() {
//just here because GWT wants it.
}
public User(String username, String password) {
this.username = username;
this.password = password;
}
}
MySQLConnection.java
package org.AwardTracker.server;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.Vector;
import com.google.gwt.user.server.rpc.RemoteServiceServlet;
import org.AwardTracker.client.DBConnection;
import org.AwardTracker.client.User;
public class MySQLConnection extends RemoteServiceServlet implements DBConnection {
private Connection conn = null;
private String status;
private String url = "jbdc:mysql://localhost/awardtracker";
private String user = "DBuser";
private String pass = "DBpass";
public MySQLConnection() {
try {
Class.forName("com.mysql.jdbc.Driver").newInstance();
conn = DriverManager.getConnection(url, user, pass);
} catch (Exception e) {
//NEVER catch exceptions like this
}
}
public int authenticateUser(String user, String pass) {
User user;
try {
PreparedStatement ps = conn.prepareStatement(
"select readonly * from users where username = \"" + user + "\" AND " + "password = \"" + pass + "\"");
ResultSet result = ps.executeQuery();
while (result.next()) {
user = new User(result.getString(1), result.getString(2));
}
result.close();
ps.close();
} catch (SQLException sqle) {
//do stuff on fail
}
return user;
}
}
Any help would be greatly appreciated.
Regards,
Glyn
Hi BenvynQ,
Thanks for your help. Just goes to show that these tutorials are not perfect. I made this change and now I get an error within authenticateUser:
while (result.next()) {
user = new User(result.getString(1), result.getString(2));
}
Of "The constructor User(String, String) is undefined".
Thanks,
Glyn
Hi Bevnq,
Thanks awfully for your help. I think there were a few "}" missing so I have modified as following.
Also, you say "User user = null; // necessary unless you do something in the exception handler
". My impression of this is that we are trying to find out if the user is in the table and return an exception if they are not (i.e., verify the username and password). Therefore, the return needs to be a confirmation and therefore we are doing something with the exveption handler. I am obviously missing something; so how do we know the user has logged in successfully?
Also, Eclipse does not seem to have an issue with mixed case for the package as I am doing this in stages and all has worked up to adding this.
Regards,
Glyn
package org.AwardTracker.server;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.Vector;
import com.google.gwt.user.server.rpc.RemoteServiceServlet;
import org.AwardTracker.client.DBConnection;
import org.AwardTracker.client.User;
public class MySQLConnection extends RemoteServiceServlet implements DBConnection {
private Connection conn = null;
private String status;
private String url = "jbdc:mysql://localhost/awardtracker";
private String user = "DBuser";
private String pass = "DBpass";
public MySQLConnection() {
try {
Class.forName("com.mysql.jdbc.Driver").newInstance();
conn = DriverManager.getConnection(url, user, pass);
} catch (Exception e) {
//NEVER catch exceptions like this
}
}
public User authenticateUser(String userName, String pass) {
User user = null; // necessary unless you do something in the exception handler
ResultSet result = null;
PreparedStatement ps = null;
try {
ps = conn.prepareStatement(
"select readonly * from users where username = \"" + userName + "\" AND " + "password = \"" + pass + "\"");
result = ps.executeQuery();
while (result.next()) {
user = new User(result.getString(1), result.getString(2));
}
}
catch (SQLException sqle) {
//do stuff on fail
}
finally {
if (result != null) {
try {
result.close();
}
catch (SQLException e) {
e.printStackTrace();
}
}
if (ps != null) {
try {
ps.close();
}
catch (SQLException e) {
e.printStackTrace();
}
}
}
return user;
}
}

You have defined the method
public int authenticateUser(String user, String pass) {
yet the object you are returning is
User user;
reading the tutorial looks like you should have declared the method
public User authenticateUser(String userName, String pass) {
User user = null; // necessary unless you do something in the exception handler
ResultSet result = null;
PreparedStatement ps = null;
try {
ps = conn.prepareStatement(
"select readonly * from users where username = \"" + userName + "\" AND " + "password = \"" + pass + "\"");
result = ps.executeQuery();
while (result.next()) {
user = new User(result.getString(1), result.getString(2));
}
} catch (SQLException sqle) {
//do stuff on fail
}finally{
if (result != null) {
try {
result.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
if (ps != null) {
try {
ps.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
return user;

Why the INSERT query doesn't work in this HttpServer code

Im trying to make a little server for my homework.This is very simple project yet i cant insert some variables (which i took from the client ,in an object form ,through serialization ) into the database .
It shows no errors! That's what i find strange and also the client receive the response without problems.
my Server class is as the following :
package server;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.OutputStream;
import java.net.InetSocketAddress;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.sql.Statement;
import org.ietf.jgss.Oid;
import com.sun.net.httpserver.HttpExchange;
import com.sun.net.httpserver.HttpHandler;
import com.sun.net.httpserver.HttpServer;
public class Server {
public static void main(String[] args) throws Exception {
HttpServer server = HttpServer.create(new InetSocketAddress(3333), 0);
server.createContext("/", new MyHandler());
server.setExecutor(null); // creates a default executor
server.start();
}
static class MyHandler implements HttpHandler {
public void handle(HttpExchange t) throws IOException {
ObjectInputStream ios = new ObjectInputStream(t.getRequestBody());
final String url = "jdbc:mysql://localhost/httpServer";
final String user = "root";
final String password = "";
try {
Send oin = (Send) ios.readObject();
String response = "Kjo eshte nje pergjigje nga serveri! \n"
+ "Clienti me id "
+ oin.getId()
+ " dhe me emer "
+ oin.getName()
+ " ka pasur "
+ oin.getAmount()
+ "$ ne llogarine e tij ,por me pas ka terhequr "
+ oin.getPaid()
+ "$ nga llogaria \n"
+ "Kjo terheqe eshte ruajtur ne database dhe tani gjendja e re eshte "
+ (oin.getAmount() - oin.getPaid()) + "$ \n";
t.sendResponseHeaders(200, response.length());
OutputStream os = t.getResponseBody();
os.write(response.getBytes());
os.close();
int id = oin.getId();
String emri = oin.getName();
int amount = oin.getAmount();
int paid = oin.getPaid();
try {
Class.forName("com.mysql.jdbc.Driver");
Connection con = DriverManager.getConnection(url, user,
password);
try {
Statement s = con.createStatement();
s.executeUpdate("INSERT INTO person VALUES ('" + id
+ "','" + emri + "','" + amount + "','" + paid
+ "')");
} catch (SQLException s) {
System.out
.println("Tabel or column or data type is not found!");
}
} catch (Exception e) {
e.printStackTrace();
}
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
}
}
}
can you please help me ?
Or have any idea what the problem may is ?
Edit:
Maybe i am doing something wrong in the Client:
package server;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.ObjectOutputStream;
import java.io.Serializable;
import java.net.HttpURLConnection;
import java.net.InetAddress;
import java.net.Socket;
import java.net.URL;
class Send implements Serializable {
// duhet te implementoje interfacin serizable ne menyre qe tja dergoj
// serverit
private static final long serialVersionUID = 1L;
public int getId() {
return id;
}
public int getAmount() {
return amount;
}
public int getPaid() {
return paid;
}
int id = 1;
int amount = 2000;
int paid = 800;
String name = "Andi Domi";
public String getName() {
return name;
}
}
public class Client {
public static void main(String[] args) throws Exception {
try {
URL url = new URL("http://localhost:3333");
HttpURLConnection s = (HttpURLConnection) url.openConnection();
s.setDoOutput(true);
s.setDoInput(true);
s.setRequestMethod("POST");
s.setUseCaches(false);
Send obj = new Send();
ObjectOutputStream objOut = new ObjectOutputStream(
s.getOutputStream());
objOut.writeObject(obj);
InputStream in = s.getInputStream();
InputStreamReader isr = new InputStreamReader(in);
BufferedReader br = new BufferedReader(isr);
int c;
while ((c = br.read()) != -1) {
System.out.print((char) c);
}
objOut.close();
s.disconnect();
} catch (IOException ex) {
System.err.println(ex);
System.err.print("gabimi eshte ketu");
}
}
}

After your executeUpdate statement you need to do.
con.commit();
to save the transaction.
EDIT: Based on the chat discussion, we learned that the column named emri is actually Emri in the table and was throwing:
com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: Unknown column 'emri' in 'field list'
Changing the name resolves the issue.
Now unrelated to your problem, you should be using a PreparedStatement instead and should be closing your connection and statement
try {
PreparedStatement s = con.prepareStatement("INSERT INTO person(id, emri, amount, paid) VALUES (?,?,?,?)");
s.setInt(1,id);
s.setString(2,emri);
s.setInt(3,amount);
s.setInt(4,paid);
int count = s.executeUpdate();
con.commit();
} catch(Exception e){
e.printStackTrace();
//something bad happened rollback
//any uncommitted changes
con.rollback();
} finally {
if (con != null) {
con.close();
}
}

first, use prepared statement[docs] to avoid from SQL INJECTION
String sql = "INSERT INTO person VALUES (?,?,?,?)";
PreparedStatement prest = con.prepareStatement(sql);
prest.setString(1,id);
prest.setString(2,emri); // or use setInt for integer
prest.setString(3,amount); // or use setInt for integer
prest.setString(4,paid);
prest.executeUpdate()
second, if the the number of values does not match the total number of columns in your table, it will also fail because you are using the implicit type of INSERT statement. To solve it, just supply the column names where you want the values should be stored, eg
String sql = "INSERT INTO person (col1, col2, col3, col4) VALUES (?,?,?,?)";

Make linked directories

I have a class that pulls in an id, name and (if needed) parent-id, it converts these into objects and then links them.
If you look right at the end you will see what Im trying to fix at the moment, The folder objects know if they have a child and/or parent but if I were to run mkDirs() here it would only work for two levels (root, child-folder) but if there were multipul levels (root/folder1/folder1) it would not work.
Any Idea how I can solve this?
package stable;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.HashMap;
import java.util.Map;
public class Loop {
public static void main(String[] args) {
int PID = 0;
int RepoID = 1;
Connection con = null;
String url = "jdbc:mysql://localhost/document_manager";
String user = "root";
String password = "Pa55w0rd";
try {
con = DriverManager.getConnection(url, user, password);
} catch (SQLException e) {
e.printStackTrace();
}
Map<Integer,Folder> data = new HashMap<Integer,Folder>();
while( PID < 50 )
{
try {
Statement st = con.createStatement();
ResultSet result = st.executeQuery("SELECT name, category_id, parent_id FROM categories WHERE parent_id = '"+PID+"' AND repository_id = '"+RepoID+"'");
while (result.next ())
{
String FolderName = result.getString ("name");
String FolderId = result.getString ("category_id");
String ParentId = result.getString ("parent_id");
int intFolderId = Integer.parseInt(FolderId);
int intParentId = Integer.parseInt(ParentId);
System.out.println( FolderId+" "+FolderName+" "+ParentId );
Folder newFolder = new Folder(FolderName, intFolderId, intParentId);
data.put(newFolder.getId(), newFolder);
}
} catch (SQLException ex) {
System.out.println(ex.getMessage());
}
PID++;
}
for(Folder folder : data.values()) {
int parentId = folder.getParentFolderId();
Folder parentFolder = data.get(parentId);
if(parentFolder != null)
parentFolder.addChildFolder(folder);
//Added
System.out.print("\n"+folder.getName());
if(parentFolder != null)
System.out.print(" IS INSIDE "+parentFolder.getName());
else
System.out.print(" HAS NO PARENT!");
}
}
}

Looks like you could/should break out the directory creation logic into its own function and then make it recursive. That should get you the ability to make 'infinite' depth directory hierarchies.
Side note: Its horribly inefficient to make repeated DB calls in a loop. Try a single Select and then loop thru results. If needbe, you can use SQL's 'IN' operator to filter results:
http://www.w3schools.com/sql/sql_in.asp