简单数据库中更新数据出错 牛人们看下啊

[colie_li]

package com.test.zhuce;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

public class Cshi {

	  
	public static void main(String[] args) throws ClassNotFoundException 
	{
	 	Connection con = null;
	    Statement sql=null;
	     ResultSet rs=null;
	     String  uid="12092401";
	     String  sid="2221";
		    Class.forName( "sun.jdbc.odbc.JdbcOdbcDriver");
	        try {
				con=DriverManager.getConnection("jdbc:odbc:lib","","");
			} catch (SQLException e) {
				
				System.out.println("执行2");
			}
			 String sqle="UPDATE yonghu set id1='"+sid+"' WHERE id="+"\'"+uid+"\'";
				try {
					sql.executeUpdate(sqle);
				} catch (SQLException e)
				{
					System.out.println("执行");
				}

	}

}

错误信息是：java.lang.NullPointerException

[likgui]

Statement sql=null;

sql= conn.createStament