Using JDBC to write a DAT file with delimiters to a database

Question

Hi Everybody
I am new to JDBC and i am trying out some small applications: I downloaded this small program and tried to compile it and and I got the following errors: ( I have MySql installed). I have to set the classpath for the driver. But I am not sure why I am gettting the NullPointerException though)
I will be very gratefull to your help. Thanks a lot..
Loading JDBC Driver -> oracle.jdbc.driver.OracleDriver
java.lang.ClassNotFoundException: oracle.jdbc.driver.OracleDriver
     at java.net.URLClassLoader$1.run(Unknown Source)
     at java.security.AccessController.doPrivileged(Native Method)
     at java.net.URLClassLoader.findClass(Unknown Source)
     at java.lang.ClassLoader.loadClass(Unknown Source)
     at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
     at java.lang.ClassLoader.loadClass(Unknown Source)
     at java.lang.ClassLoader.loadClassInternal(Unknown Source)
     at java.lang.Class.forName0(Native Method)
     at java.lang.Class.forName(Unknown Source)
     at us.ilango.WriteFileToTable.<init>(WriteFileToTable.java:69)
     at us.ilango.WriteFileToTable.main(WriteFileToTable.java:367)
java.lang.NullPointerException
     at us.ilango.WriteFileToTable.createTable(WriteFileToTable.java:97)
     at us.ilango.WriteFileToTable.main(WriteFileToTable.java:368)
Exception in thread "main"
the Program is as follows:
package us.ilango;
import java.sql.DriverManager;
import java.sql.Connection;
import java.sql.Statement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.StringTokenizer;
import java.io.FileReader;
import java.io.BufferedReader;
import java.io.IOException;
import java.util.Date;
import java.text.SimpleDateFormat;
import java.text.NumberFormat;
import java.text.ParseException;
* The following class provides an example of how to read a simple text file
* of records and then insert them into a table in a database. A text file
* named Employee.txt will contain employee records to be inserted into the
* following table:
*      SQL> desc emp
*      Name              Null?    Type
*      EMP_ID              NOT NULL NUMBER
*      DEPT_ID                      NUMBER
*      NAME                NOT NULL VARCHAR2(30)
*      DATE_OF_BIRTH       NOT NULL DATE
*      DATE_OF_HIRE        NOT NULL DATE
*      MONTHLY_SALARY      NOT NULL NUMBER(15,2)
*      POSITION            NOT NULL VARCHAR2(100)
*      EXTENSION                    NUMBER
*      OFFICE_LOCATION              VARCHAR2(100)
* NOTE: This example will provide and call a method that creates the EMP
*       table. The name of the method is called createTable() and is called
*       from the main() method.
public class WriteFileToTable {
    final static String driverClass    = "oracle.jdbc.driver.OracleDriver";
    final static String connectionURL  = "jdbc:oracle:thin:@localhost:1521:CUSTDB";
    final static String userID         = "scott";
    final static String userPassword   = "tiger";
    final static String inputFileName  = "Employee.txt";
    final static String TABLE_NAME     = "EMP";
    final static String DELIM          = ",";
    Connection   con                   = null;
     * Construct a WriteFileToTable object. This constructor will create an
     * Oracle database connection.
    public WriteFileToTable() {
        try {
            System.out.print("  Loading JDBC Driver  -> " + driverClass + "\n");
            Class.forName(driverClass).newInstance();
            System.out.print("  Connecting to        -> " + connectionURL + "\n");
            this.con = DriverManager.getConnection(connectionURL, userID, userPassword);
            System.out.print("  Connected as         -> " + userID + "\n");
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (InstantiationException e) {
            e.printStackTrace();
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        } catch (SQLException e) {
            e.printStackTrace();
     * Method used to create the initial EMP table. Before attempting to create
     * the table, this method will first try to drop the table.
    public void createTable() {
        Statement stmt = null;
        try {
            stmt = con.createStatement();
            System.out.print("  Dropping Table: " + TABLE_NAME + "\n");
            stmt.executeUpdate("DROP TABLE " + TABLE_NAME);
            System.out.print("    - Dropped Table...\n");
            System.out.print("  Closing Statement...\n");
            stmt.close();
        } catch (SQLException e) {
            System.out.print("    - Table " + TABLE_NAME + " did not exist.\n");
        try {
            stmt = con.createStatement();
            System.out.print("  Creating Table: " + TABLE_NAME + "\n");
            stmt.executeUpdate("CREATE TABLE emp (" +
                             "    emp_id           NUMBER NOT NULL " +
                             "  , dept_id          NUMBER " +
                             "  , name             VARCHAR2(30)  NOT NULL " +
                             "  , date_of_birth    DATE          NOT NULL " +
                             "  , date_of_hire     DATE          NOT NULL " +
                             "  , monthly_salary   NUMBER(15,2)  NOT NULL " +
                             "  , position         VARCHAR2(100) NOT NULL " +
                             "  , extension        NUMBER " +
                             "  , office_location  VARCHAR2(100))");
            System.out.print("    - Created Table...\n");
            System.out.print("  Closing Statement...\n");
            stmt.close();
        } catch (SQLException e) {
            e.printStackTrace();
     * Method used to read records from Employee.txt file then write the records
     * to an Oracle table within the database named "EMP".
    public void performLoadWrite() {
        Statement stmt          = null;
        int       insertResults = 0;
        StringTokenizer st = null;
        String  emp_id;
        String  dept_id;
        String  name;
        String  date_of_birth;
        String  date_of_hire;
        String  monthly_salary;
        String  position;
        String  extension;
        String  office_location;
        try {
            System.out.print("  Creating Statement...\n");
            stmt = con.createStatement ();
            System.out.print("  Create FileReader Object for file: " + inputFileName + "...\n");
            FileReader inputFileReader = new FileReader(inputFileName);
            System.out.print("  Create BufferedReader Object for FileReader Object...\n");
            BufferedReader inputStream   = new BufferedReader(inputFileReader);
            String inLine = null;
            while ((inLine = inputStream.readLine()) != null) {
                st = new StringTokenizer(inLine, DELIM);
                emp_id   = st.nextToken();
                dept_id  = st.nextToken();
                name     = st.nextToken();
                date_of_birth = st.nextToken();
                date_of_hire = st.nextToken();
                monthly_salary = st.nextToken();
                position = st.nextToken();
                extension = st.nextToken();
                office_location = st.nextToken();
                System.out.print("  Inserting value for [" + name + "]\n");
                insertResults = stmt.executeUpdate(
                        "INSERT INTO " + TABLE_NAME + " VALUES (" +
                                  emp_id +
                        "  ,  " + dept_id +
                        "  , '" + name + "'" +
                        "  , '" + date_of_birth + "'" +
                        "  , '" + date_of_hire + "'" +
                        "  ,  " + monthly_salary +
                        "  , '" + position + "'" +
                        "  ,  " + extension +
                        "  , '" + office_location + "')");
                System.out.print("    " + insertResults + " row created.\n");
            System.out.print("  Commiting Transaction...\n");
            con.commit();
            System.out.print("  Closing inputString...\n");
            inputStream.close();
            System.out.print("  Closing Statement...\n");
            stmt.close();
        } catch (SQLException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
     * Method used to query records from the database table EMP. This method
     * can be used to verify all records have been correctly loaded from the
     * example text file "Employee.txt".
    public void queryRecords() {
        Statement stmt           = null;
        ResultSet rset           = null;
        int       deleteResults  = 0;
        int       rowNumber      = 0;
        int     emp_id;
        int     dept_id;
        String  name;
        String  date_of_birth;
        Date    date_of_birth_p;
        String  date_of_hire;
        Date    date_of_hire_p;
        float   monthly_salary;
        String  position;
        int     extension;
        String  office_location;
        try {
            SimpleDateFormat formatter      = new SimpleDateFormat("yyyy-MM-dd");
            NumberFormat     defaultFormat  =     NumberFormat.getCurrencyInstance();
            System.out.print("  Creating Statement...\n");
            stmt = con.createStatement ();
            System.out.print("  Opening query for table: " + TABLE_NAME + "...\n");
            rset = stmt.executeQuery ("SELECT * FROM emp ORDER BY emp_id");
            while (rset.next ()) {
                rowNumber = rset.getRow();
                emp_id = rset.getInt(1);
                if ( rset.wasNull() )   {emp_id = -1;}
                dept_id = rset.getInt(2);
                if ( rset.wasNull() )   {dept_id = -1;}
                name = rset.getString(3);
                if ( rset.wasNull() )   {name = "<null>";}
                date_of_birth = rset.getString(4);
                if ( rset.wasNull() ) {date_of_birth = "1900-01-01";}
                try {
                    date_of_birth_p = formatter.parse(date_of_birth);
                } catch (ParseException e) {
                    date_of_birth_p = new Date(0);
                date_of_hire = rset.getString(5);
                if ( rset.wasNull() ) {date_of_hire = "1900-01-01";}
                try {
                    date_of_hire_p = formatter.parse(date_of_hire);
                } catch (ParseException e) {
                    date_of_hire_p = new Date(0);
                monthly_salary = rset.getFloat(6);
                if ( rset.wasNull() ) {monthly_salary = 0;}
                position = rset.getString(7);
                if ( rset.wasNull() ) {position = "<null>";}
                extension = rset.getInt(8);
                if ( rset.wasNull() )   {extension = -1;}
                office_location = rset.getString(9);
                if ( rset.wasNull() ) {office_location = "<null>";}
                System.out.print(
                    "\n" +
                    "  RESULTS -> [R" + rowNumber + "] " + "\n" +
                    "      Employee ID     : " + emp_id + "\n" +
                    "      Department ID   : " + dept_id + "\n" +
                    "      Employee Name   : " + name + "\n" +
                    "      D.O.B.          : " + date_of_birth_p + "\n" +
                    "      Date of Hire    : " + date_of_hire_p + "\n" +
                    "      Monthly Salary  : " + defaultFormat.format(monthly_salary) + "\n" +
                    "      Position        : " + position + "\n" +
                    "      Extension       : x" + extension + "\n" +
                    "      Office Location : " + office_location +
                    "\n");
            System.out.print("  Closing ResultSet...\n");
            rset.close();
            System.out.print("  Closing Statement...\n");
            stmt.close();
        } catch (SQLException e) {
            e.printStackTrace();
     * Close down Oracle connection.
    public void closeConnection() {
        try {
            System.out.print("  Closing Connection...\n");
            con.close();
        } catch (SQLException e) {
            e.printStackTrace();
     * Sole entry point to the class and application.
     * @param args Array of String arguments.
     * @exception java.lang.InterruptedException
     *            Thrown from the Thread class.
    public static void main(String[] args)
            throws java.lang.InterruptedException {
        WriteFileToTable runExample = new WriteFileToTable();
        runExample.createTable();
        runExample.performLoadWrite();
        runExample.queryRecords();
        runExample.closeConnection();
    }

Answer 1

Hi
Thanks a lot. I ran the program with the MySql driver as follows:
The errors are as follows: I will ttry to place the Driver in the Classpath. As far as I know the driver has been specified correctly this time.
java.lang.ClassNotFoundException: com.mysql.jdbc.Driver
     at java.net.URLClassLoader$1.run(Unknown Source)
     at java.security.AccessController.doPrivileged(Native Method)
     at java.net.URLClassLoader.findClass(Unknown Source)
     at java.lang.ClassLoader.loadClass(Unknown Source)
     at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
     at java.lang.ClassLoader.loadClass(Unknown Source)
     at java.lang.ClassLoader.loadClassInternal(Unknown Source)
     at java.lang.Class.forName0(Native Method)
     at java.lang.Class.forName(Unknown Source)
     at us.ilango.WriteAntennas.<init>(WriteAntennas.java:41)
     at us.ilango.WriteAntennas.main(WriteAntennas.java:377)
java.lang.NullPointerException
     at us.ilango.WriteAntennas.createTable(WriteAntennas.java:70)
     at us.ilango.WriteAntennas.main(WriteAntennas.java:378)
Exception in thread "main" Loading JDBC Driver -> com.mysql.jdbc.Driver
The program is as follows:
package us.ilango;
* @author ilango
import java.sql.DriverManager;
import java.sql.Connection;
import java.sql.Statement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.StringTokenizer;
import java.io.FileReader;
import java.io.BufferedReader;
import java.io.IOException;
public class WriteAntennas {
    final static String driverClass    = "com.mysql.jdbc.Driver";
    final static String connectionURL  = "jdbc:mysql://localhost/test2";
    final static String userID         = "brian";
    final static String userPassword   = " ";
    final static String inputFileName  = "CO.DAT";
    final static String TABLE_NAME     = "CELL";
    final static String DELIM          = "|";
    Connection   con                   = null;
    public WriteAntennas() {
        try {
            System.out.print("  Loading JDBC Driver  -> " + driverClass + "\n");
            Class.forName(driverClass).newInstance();
            System.out.print("  Connecting to        -> " + connectionURL + "\n");
            this.con = DriverManager.getConnection(connectionURL, userID, userPassword);
            System.out.print("  Connected as         -> " + userID + "\n");
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (InstantiationException e) {
            e.printStackTrace();
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        } catch (SQLException e) {
            e.printStackTrace();
     * Method used to create the initial EMP table. Before attempting to create
     * the table, this method will first try to drop the table.
    public void createTable() {
        Statement stmt=null;
        try {
            stmt = con.createStatement();
            System.out.print("  Dropping Table: " + TABLE_NAME + "\n");
            stmt.executeUpdate("DROP TABLE " + TABLE_NAME);
            System.out.print("    - Dropped Table...\n");
            System.out.print("  Closing Statement...\n");
            stmt.close();
        } catch (SQLException e) {
            System.out.print("    - Table " + TABLE_NAME + " did not exist.\n");
        try {
            stmt = con.createStatement();
            System.out.print("  Creating Table: " + TABLE_NAME + "\n");
            stmt.executeUpdate("create table TOWER_PUBACC_CO (" +
     "record_type               char(2)              null" +
     ", content_indicator         char(3)              null" +
     ", file_number               char(8)              null" +
     ", registration_number       char(7)              null" +
     ", unique_system_identifier  long(9,0)         not null" +
     ", coordinate_type           char(1)              not null" +
     ",latitude_degrees          int                  null" +
     ",latitude_minutes          int                  null" +
     ",latitude_seconds          int(4,1)         null" +
     ",latitude_direction        char(1)              null" +
     ",latitude_total_seconds    int(8,1)         null" +
     ",longitude_degrees         int                  null" +
     ",longitude_minutes         int                  null" +
     ",longitude_seconds         int(4,1)         null" +
     ",longitude_direction       char(1)              null" +
     ",longitude_total_seconds   int(8,1)         null)" );
            System.out.print("   created Table...\n");
            System.out.print("  closing Statement...\n");
            stmt.close();
        } catch (SQLException e) {
            e.printStackTrace();
    public void performLoadWrite() {
        Statement stmt          = null;
        int       insertResults = 0;
        StringTokenizer st = null;
        String record_type ;
        String  content_indicator;
        String file_number ;
        String registration_number;
         String unique_system_identifier ;
        String coordinate_type;
        String latitude_degrees;
        String  latitude_minutes;
        String latitude_seconds;
        String latitude_direction;
        String latitude_total_seconds;
        String longitude_degrees;
       String longitude_minutes;
       String longitude_seconds;
       String longitude_direction;
       String longitude_total_seconds;
        try {
            System.out.print("  Creating Statement...\n");
            stmt = con.createStatement ();
            System.out.print("  Create FileReader Object for file: " + inputFileName + "...\n");
            FileReader inputFileReader = new FileReader(inputFileName);
            System.out.print("  Create BufferedReader Object for FileReader Object...\n");
            BufferedReader inputStream   = new BufferedReader(inputFileReader);
            String inLine = null;
            while ((inLine = inputStream.readLine()) != null) {
                st = new StringTokenizer(inLine, DELIM);
                record_type   = st.nextToken();
               content_indicator = st.nextToken();
                file_number    = st.nextToken();
                registration_number = st.nextToken();
                unique_system_identifier = st.nextToken();
               coordinate_type =st.nextToken();
               latitude_degrees  = st.nextToken();
               latitude_minutes = st.nextToken();
                latitude_seconds=st.nextToken();
               latitude_direction = st.nextToken();
                latitude_total_seconds =st.nextToken();
                longitude_degrees= st.nextToken();
                longitude_minutes = st.nextToken();
                longitude_seconds = st.nextToken();
                longitude_direction=st.nextToken();
                longitude_total_seconds =st.nextToken();
                System.out.print("  Inserting value for [" + unique_system_identifier + "]\n");
                insertResults = stmt.executeUpdate(
                        "INSERT INTO " + TABLE_NAME + " VALUES (" +
                                  record_type +
                        "  ,  " + content_indicator +
                        "  , '" + file_number + "'" +
                        "  , '" + registration_number + "'" +
                        "  , '" + unique_system_identifier + "'" +
                        "  ,  " + coordinate_type + "'" +
                        "  , '" + latitude_degrees + "'" +
                        "  ,  " + latitude_minutes + "'" +
                        "  , '" + latitude_seconds + "'" +
                        "  , '" + latitude_direction + "'" +
                        "  , '" + latitude_total_seconds + "'" +
                       "  , '" + longitude_minutes + "'" +
                       "  , '" + longitude_seconds + "'" +
                      "  , '" + longitude_direction + "'" +
                       "  , '" + longitude_total_seconds + "')");
                System.out.print("    " + insertResults + " row created.\n");
            System.out.print("  Commiting Transaction...\n");
            con.commit();
            System.out.print("  Closing inputString...\n");
            inputStream.close();
            System.out.print("  Closing Statement...\n");
            stmt.close();
        } catch (SQLException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
    public void queryRecords() {
        Statement stmt           = null;
        ResultSet rset           = null;
        int       deleteResults  = 0;
        int       rowNumber      = 0;
        String   record_type;
        String   content_indicator;
        String  file_number;
        String registration_number ;
        long  unique_system_identifier;
        String coordinate_type ;
        int   latitude_degrees ;
        int latitude_minutes ;
        int latitude_seconds;
        String latitude_direction;
        int  latitude_total_seconds;
        int     longitude_degrees;
         int longitude_minutes;
           int     longitude_seconds;
             String longitude_direction;
       int  longitude_total_seconds;
        try {
            System.out.print("  Creating Statement...\n");
            stmt = con.createStatement ();
            System.out.print("  Opening query for table: " + TABLE_NAME + "...\n");
            rset = stmt.executeQuery ("SELECT * FROM cell ORDER BY unique_system_identifier");
            while (rset.next ()) {
                rowNumber = rset.getRow();
                unique_system_identifier = rset.getInt (1);
                if ( rset.wasNull() )   {unique_system_identifier = -1;}
                record_type = rset.getString (2);
                if ( rset.wasNull() )   {record_type = "<null>";}
                content_indicator = rset.getString(3);
                if ( rset.wasNull() )   {content_indicator = "<null>";}
                file_number = rset.getString(4);
                if ( rset.wasNull() ) {file_number = "<null>";}
                registration_number = rset.getString(5);
                if ( rset.wasNull() ) {registration_number = "<null>";}
                coordinate_type = rset.getString(6);
                if ( rset.wasNull() )   {coordinate_type = "<null>";}
                latitude_degrees = rset.getInt(7);
                if ( rset.wasNull() ) {latitude_degrees = 1;}
latitude_minutes = rset.getInt(8);
                if ( rset.wasNull() ) {latitude_minutes = 1;}
latitude_seconds = rset.getInt(9);
                if ( rset.wasNull() ) {latitude_seconds = 1;}
latitude_direction = rset.getString(10);
                if ( rset.wasNull() ) {latitude_direction = "<null>";}
latitude_total_seconds = rset.getInt(11);
                if ( rset.wasNull() ) {latitude_total_seconds = 1;}
longitude_degrees = rset.getInt(12);
                if ( rset.wasNull() ) {longitude_degrees = 1;}
longitude_minutes = rset.getInt(13);
                if ( rset.wasNull() ) {longitude_minutes = 1;}
longitude_seconds = rset.getInt(14);
                if ( rset.wasNull() ) {longitude_seconds = 1;}
longitude_direction = rset.getString(15);
                if ( rset.wasNull() ) {longitude_direction = "<null>";}
longitude_total_seconds = rset.getInt(16);
                if ( rset.wasNull() ) {longitude_total_seconds = 1;}
                System.out.print(
                    "\n" +
                    "  RESULTS -> [R" + rowNumber + "] " + "\n" +
                    "  Unique_System_Identifier         : " + unique_system_identifier  + "\n" +
                    "  Record_type     : " + record_type   + "\n" +
                    "  Content_Indicator      : " + content_indicator   + "\n" +
                    "  Registration_Number              : " + registration_number   + "\n" +
                    "  File_Number        : " +  file_number  + "\n" +
                    "  Coordinate_Type     : " + coordinate_type  + "\n" +
                    "  Latitude_Degrees          : " + latitude_degrees + "\n" +
                    "  Latitude_Minutes          : " + latitude_minutes + "\n" +
                    "  Latitude_Seconds           : " + latitude_seconds + "\n" +
                    " Latitude_Direction            : " + latitude_direction + "\n" +
                    "  Latitude_Total_Seconds           : " + latitude_total_seconds + "\n" +
                    "  Longitude_Degrees           : " + longitude_degrees + "\n" +
                    "  longitude_minutes           : " + longitude_minutes + "\n" +
                    "  Longitude_Seconds           : " + longitude_seconds + "\n" +
                   "     longitude_direction        : " + longitude_direction + "\n" +
                   "  Longitude_Total_Seconds           : " + longitude_total_seconds +
                   "\n");
            System.out.print("  Closing ResultSet...\n");
            rset.close();
            System.out.print("  Closing Statement...\n");
            stmt.close();
        } catch (SQLException e) {
            e.printStackTrace();
    public void closeConnection() {
        try {
            System.out.print("  Closing Connection...\n");
            con.close();
        } catch (SQLException e) {
            e.printStackTrace();
    public static void main(String[] args)
            throws java.lang.InterruptedException {
        WriteAntennas runJob = new WriteAntennas();
        runJob.createTable();
        runJob.performLoadWrite();
        runJob.queryRecords();
        runJob.closeConnection();
}