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  1. #1
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    Set a classpath for mysql and java connectivity

    hi,

    when i run a java program for to store data and retrive using mysql datatabse i got the following errors.I think in that one of error is due to set the class path.I placed my mysql-connector-java-3.0.11-stable-bin jar in lib directory.What is the command to set a classpath in windows for java mysql connectivity.plz tell that .And also how i avoid these errors.

    Code:
    import java.sql.*;
    import java.util.*;
    import java.net.*;
    import java.io.*;
    import java.sql.Connection;
    import java.sql.DriverManager;
    import java.sql.SQLException;
    import java.sql.*;
    class Test
    {
    public static void main(String args[])
    {
    Class.forName("org.gjt.mm.mysql.Driver").newInstance();
    //dbCon = DriverManager.getConnection("jdbc:mysql://194.230.33.43/databasename", "phoneliv_root", "root");
    dbCon = DriverManager.getConnection("jdbc:mysql://localhost:3306/DataMiningdb","root","root");
    Connection dbCon;
    ResultSet rsGroups;
    Statement stmtSql;
    String strSql="", strToMobileNo = "", strMemberName = "", groupId = "";
    
    /*
    ** The Statement enables the resultset obtained from it to be scrollable and read only.
    */
    stmtSql = dbCon.createStatement(ResultSet.TYPE_SCROLL_INSENS ITIVE, ResultSet.CONCUR_READ_ONLY);
    /*
    ** The List of the groups are retrieved and displayed.
    */
    stmtSql = dbCon.createStatement(ResultSet.TYPE_SCROLL_INSENS ITIVE, ResultSet.CONCUR_READ_ONLY);
    strSql = "Select * from vehicles";
    rsGroups = stmtSql.executeQuery(strSql);
    while(rsGroups.next()){
    strMemberName = rsGroups.getInt("vehicle_id");
    strToMobileNo = rsGroups.getString("vehicle_stockno");
    groupId = rsGroups.getString("vehicle_make");
    }
    System.out.println("strToMobileNo");
    System.out.println("strMemberName");
    System.out.println("groupId");
    }
    }
    errors :

    C:\j2sdk1.4.0\bin>javac dbcon.java
    dbcon.java:15: cannot resolve symbol
    symbol : variable dbCon
    location: class Test
    dbCon = DriverManager.getConnection("jdbc:mysql://localhost:3306/DataMiningdb","root
    ","root");
    ^
    dbcon.java:32: incompatible types
    found : int
    required: java.lang.String
    strMemberName = rsGroups.getInt("vehicle_id");
    ^
    2 errors

    plz help me.
    Last edited by Aradon; 08-04-2008 at 10:40 AM.

  • #2
    ess
    ess is offline
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    see this howto to configure java installation on windows
    http://www.cs.ucsb.edu/~teliot/Path_and_Classpath.htm

    and this guide (at the bottom) for mysql etc
    http://eil.stanford.edu/neesgrid/dat...src/README.txt

    cheers
    ~E
    Last edited by ess; 08-04-2008 at 08:01 AM.

  • #3
    Senior Coder shyam's Avatar
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    Quote Originally Posted by swethak View Post
    when i run a java program for to store data and retrive using mysql datatabse i got the following errors.I think in that one of error is due to set the class path.I placed my mysql-connector-java-3.0.11-stable-bin jar in lib directory.What is the command to set a classpath in windows for java mysql connectivity.plz tell that .And also how i avoid these errors.
    from your example you haven't actually run ur program...u have just compiled it. heres how you set the classpath in windows...
    Code:
    set CLASSPATH=%CLASSPATH%;c:\my-app\lib\driver.jar;
    or you could also add an entry in the My Computer->properties->advanced->environment variables

    Quote Originally Posted by swethak View Post
    Code:
    import java.sql.*;
    import java.util.*;
    import java.net.*;
    import java.io.*;
    import java.sql.Connection;
    import java.sql.DriverManager;
    import java.sql.SQLException;
    import java.sql.*;
    class Test
    {
    public static void main(String args[])
    {
    Class.forName("org.gjt.mm.mysql.Driver").newInstance();
    //dbCon = DriverManager.getConnection("jdbc:mysql://194.230.33.43/databasename", "phoneliv_root", "root");
    dbCon = DriverManager.getConnection("jdbc:mysql://localhost:3306/DataMiningdb","root","root");
    Connection dbCon;
    ResultSet rsGroups;
    Statement stmtSql;
    String strSql="", strToMobileNo = "", strMemberName = "", groupId = "";
    
    /*
    ** The Statement enables the resultset obtained from it to be scrollable and read only.
    */
    stmtSql = dbCon.createStatement(ResultSet.TYPE_SCROLL_INSENS ITIVE, ResultSet.CONCUR_READ_ONLY);
    /*
    ** The List of the groups are retrieved and displayed.
    */
    stmtSql = dbCon.createStatement(ResultSet.TYPE_SCROLL_INSENS ITIVE, ResultSet.CONCUR_READ_ONLY);
    strSql = "Select * from vehicles";
    rsGroups = stmtSql.executeQuery(strSql);
    while(rsGroups.next()){
    strMemberName = rsGroups.getInt("vehicle_id");
    strToMobileNo = rsGroups.getString("vehicle_stockno");
    groupId = rsGroups.getString("vehicle_make");
    }
    System.out.println("strToMobileNo");
    System.out.println("strMemberName");
    System.out.println("groupId");
    }
    }

    Quote Originally Posted by swethak View Post
    C:\j2sdk1.4.0\bin>javac dbcon.java
    dbcon.java:15: cannot resolve symbol
    symbol : variable dbCon
    location: class Test
    dbCon = DriverManager.getConnection("jdbc:mysql://localhost:3306/DataMiningdb","root
    ","root");
    ^
    you are using dbConn before even declaring it...see above the code highlighted in red

    Quote Originally Posted by swethak View Post
    dbcon.java:32: incompatible types
    found : int
    required: java.lang.String
    strMemberName = rsGroups.getInt("vehicle_id");
    ^
    2 errors
    here again you are trying to assign an int to a string variable...

    if you had just read the errors thrown by the compiler you could have solved these problems, please find a good java tutorial and learn
    You never have to change anything you got up in the middle of the night to write. -- Saul Bellow


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