Connect to mySQL using eclipse

Question

I am trying to run a JAVA program which inserts values into mySQL database. When I run the program, it says

 Connection refused: connect 

I have included mySQL jars also. What is the problem? Can anyone help me out

 import java.sql.Connection;
 import java.sql.DriverManager;
 import java.sql.SQLException;
 import java.sql.Statement;
 import java.text.DateFormat;
 import java.text.SimpleDateFormat;
 import java.util.Calendar;
 import java.util.Date;

 public class DataLogs {
  public static void main(String[] args) throws SQLException,ClassNotFoundException {
      Connection connection = null;
      try {
          //int i=0;
          String strDate="", strTime="";
          // Register MySQL JDBC driver to be known by
          // the DriverManager object.
          Class.forName("com.mysql.jdbc.Driver");
          // Get a connection to database. We prepare the
          // connection information here such as database
          // url, user and password.
          String url = "jdbc:mysql://localhost:8080/sampledatabase";
          String user = "root";
          String password = "root";
          connection = DriverManager.getConnection(url, user, password);
          // Create a statement object instance from the
          // connection
          Statement stmt = connection.createStatement();
          // We are going to execute an insert statement.
          // First you have to create a table that has an
          // ID, NAME and ADDRESS field. For ID you can use
          // an auto number, while NAME and ADDRESS are
          // VARCHAR fields.                   

              for(int i=1;i<=100;i++){
                  Date date = new Date();
                  SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd hh:mm:ss");
                  String formattedDate = sdf.format(date);
                  strDate=getFormatedDate();
                  strTime=getTime();
                  String mm=strDate.substring(3, 5);
                  String yy=strDate.substring(8, 10);
                  String hh=strTime.substring(0, 2);
                  String mi=strTime.substring(3, 5);
                  String ss=strTime.substring(6, 8);
                  String dd=strDate.substring(0, 2);
                  String date1 = ""+yy+"-"+mm+"-"+dd+" "+hh+":"+mi+":"+ss;
                  String sql= "INSERT INTO `site_values_"+i+"` VALUES("+i+",5316,0,0,130,89,904,171,1006,96,4000,"+ss+","+mi+","+hh+","+dd+","+mm+","+yy+",84753,0,0,0,0,0,0,0,0,0,'Short Circuit Shutdown','Shutdown',1,'"+date1+"')";
                  // Call an execute method in the statement object
                  // and passed the sql or query string to it.
                  stmt.execute(sql);

              }

          // After this statement is executed you'll have a
          // record in your users table.
      } catch (ClassNotFoundException e) {
          System.err.println("Could not load database driver!"+e);
      } catch (SQLException e) {
          e.printStackTrace();
      } finally {
          if (connection != null) {
              connection.close();
          }
      }
  }
  public static String getFormatedDate() {
      String strDate="";
      Calendar cal = Calendar.getInstance();
      SimpleDateFormat sdfdate = new SimpleDateFormat("dd/MM/yyyy");
      strDate= sdfdate.format(cal.getTime());
      return strDate;
  }//getFormatedDate

  public static String getTime() {
      DateFormat dateFormat = new SimpleDateFormat("HH:mm:ss");
      java.util.Date date = new java.util.Date();
      String datetime = dateFormat.format(date);
      return datetime;
  } //getTime

}

This is what I see in the console

            com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure

  The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
at java.lang.reflect.Constructor.newInstance(Unknown Source)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:411)
at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:1116)
at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:344)
at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2332)
at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2369)
at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2153)
at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:792)
at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:47)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
at java.lang.reflect.Constructor.newInstance(Unknown Source)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:411)
at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:381)
at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:305)
at java.sql.DriverManager.getConnection(Unknown Source)
at java.sql.DriverManager.getConnection(Unknown Source)
at solarnmsstandard.DataLogs.main(DataLogs.java:27)
Caused by: java.net.ConnectException: Connection refused: connect
at java.net.DualStackPlainSocketImpl.connect0(Native Method)
at java.net.DualStackPlainSocketImpl.socketConnect(Unknown Source)
at java.net.AbstractPlainSocketImpl.doConnect(Unknown Source)
at java.net.AbstractPlainSocketImpl.connectToAddress(Unknown Source)
at java.net.AbstractPlainSocketImpl.connect(Unknown Source)
at java.net.PlainSocketImpl.connect(Unknown Source)
at java.net.SocksSocketImpl.connect(Unknown Source)
at java.net.Socket.connect(Unknown Source)
at java.net.Socket.connect(Unknown Source)
at java.net.Socket.<init>(Unknown Source)
at java.net.Socket.<init>(Unknown Source)
at com.mysql.jdbc.StandardSocketFactory.connect(StandardSocketFactory.java:257)
at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:294)
... 15 more

Answer 1

Check if your connection parameters are correct (username, password) and especially the port where the MySql server is running.

Answer 2

check whether your mysql server is running or not, if it is not running then you will get this exception

java.net.ConnectException: Connection refused: connect

to run server

go to <mysql installation path>/bin/ and run mysqld.. to start the mysql server.

even after if you get the same error, provide the full stack trace.

Answer 3

check your port 8080 is free or not

if you are use linux run the follwing command and restart your server.

sudo kill sudo lsof -t -i:8080 sudo kill sudo lsof -t -i:8005 sudo kill sudo lsof -t -i:8009

Answer 4

I would be very suspicious of port 8080 being used as the port for MySQL; it really should be port 3306. So that would have to be checked properly as 8080 is usually the port number for an Application Server instance (such as GlassFish or Tomcat).