dbclass.java

自己写的一个JAVA实现的学生成绩管理系统

import java.sql.*;
import java.util.Iterator;
import java.sql.ResultSet;
import java.sql.Connection;
import java.sql.Statement;
import java.sql.SQLException;
import java.sql.DriverManager;

public class DBClass
{
   String url = "jdbc:oracle:thin:@127.0.0.1:1521:oracle";
   //url="jdbc:microsoft:sqlserver://localhost:1433;DatabaseName=pubs";
   private Connection sqlCon;//连接
   private Statement pstmt;//连接状态
   ResultSet rs;//结果集
   public DBClass ()
   {
      sqlCon = null;
      pstmt = null;
      rs = null;
   }
   public ResultSet executeSQL(String SQLString, String databaseString)
   {
      try
      {
         Class.forName("oracle.jdbc.driver.OracleDriver").newInstance();//注册
         sqlCon = DriverManager.getConnection(url, "scott", "tiger");
         //sqlCon.setCatalog(studentdb);
         sqlCon.setAutoCommit(true);
         String sqlString = SQLString.trim();
         //pstmt = sqlCon.prepareStatement(sqlString);
         pstmt = sqlCon.createStatement();
         if(sqlString.substring(0, 1).equals("s"))
         {
            rs = pstmt.executeQuery(sqlString);
            return rs;
         }
         else
         {
            pstmt.executeUpdate(sqlString);
         }
      }
      catch(InstantiationException e)
      {
         e.printStackTrace();//To change body of catch statement use Options | File Templates.
      }
      catch(IllegalAccessException e)
      {
         e.printStackTrace();//To change body of catch statement use Options | File Templates.
      }
      catch(ClassNotFoundException e)
      {
         e.printStackTrace();//To change body of catch statement use Options | File Templates.
      }
      catch(SQLException e)
      {
         e.printStackTrace();//To change body of catch statement use Options | File Templates.
      }
      return null;
   }
   public void closeDatabase() throws SQLException
   {
      if(rs != null)
         rs.close();
      if(pstmt != null)
         pstmt.close();
      if(sqlCon != null)
         sqlCon.close();
   }
   public static void main(String[] args) throws Exception
   {
      DBClass a = new DBClass();
      a.executeSQL("select * from student", "studentdatabase");
      if(a.rs.next())
         System.out.println(a.rs.getString("name"));
   }
}