学生管理系统 源代码

http://www.blogjava.net/chenglu/archive/2009/06/08/Student_Manager.html
DB.java

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package opera.DB;
import java.sql.*;
import java.util.logging.Level;
import java.util.logging.Logger;
/**
*
* @author soft
*/
public class DB {
    private String sName;
    private String Sno;
    private String Sgrade;
    private String Ssex;
    private String QSql;
    private Statement stm= null ;
    private ResultSet rs = null ;
    private int i = 0 ;
    private String ex;
    private String usn;
    private String pwd;
   
    public Connection getCon (){
      Connection con= null ;
      try {
        Class.forName ( "com.mysql.jdbc.Driver" ) ;
         con = DriverManager.getConnection ( "jdbc:mysql://localhost:3306/stu" , "root" , "" ) ;
      } catch ( SQLException ex ) {
        ex.printStackTrace () ;
      } catch ( ClassNotFoundException ex ) {
        ex.printStackTrace () ;
      }
      return con;
    }
    /**
     * @return the sName
     */
    public String getSName () {
        return sName;
    }

    /**
     * @param sName the sName to set
     */
    public void setSName ( String sName ) {
        this .sName = sName;
    }

    /**
     * @return the Sno
     */
    public String getSno () {
        return Sno;
    }

    /**
     * @param Sno the Sno to set
     */
    public void setSno ( String Sno ) {
        this .Sno = Sno;
    }

    /**
     * @return the Sgrade
     */
    public String getSgrade () {
        return Sgrade;
    }

    /**
     * @param Sgrade the Sgrade to set
     */
    public void setSgrade ( String Sgrade ) {
        this .Sgrade = Sgrade;
    }
    /**
     * @return the Ssex
     */
        public String getSsex () {
        return Ssex;
    }

    /**
     * @param Ssex the Ssex to set
     */
    public void setSsex ( String Ssex ) {
        this .Ssex = Ssex;
    }


    public int DBinsert ( int choice ) throws SQLException {
        //Connection con =null;

            //Class.forName("com.mysql.jdbc.Driver");
            //con = DriverManager.getConnection("jdbc:mysql://localhost:3306/stu","root","");
            stm = getCon () .createStatement () ;
            if ( choice== 1 ){
            i = stm.executeUpdate ( "insert into stu values('" +getSno () + "','" +getSName () + "','" +getSsex () + "','" +getSgrade () + "')" ) ;
            }
            else if ( choice== 2 ){
            i = stm.executeUpdate ( "insert into user values('" +getUsn () + "','" +getPwd () + "')" ) ;
            } //关闭
            getCon () .close () ;
            stm.close () ;
           stm = null ;
        return i;
    }
    public void DBQuery ( int check ) throws SQLException { //throws Exception{
  
      //ResultSet rs = null;
      //Statement stm = null;
      stm = getCon () .createStatement () ;
      rs = stm.executeQuery ( getQSql ()) ;
      //select * from stu where sno = getSno()getQSql()
      if ( check== 1 ){
        //获取
      while ( rs.next ()){
      setSno ( rs.getString ( "sno" )) ;
      setSName ( rs.getString ( "sName" )) ;
      setSsex ( rs.getString ( "ssex" )) ;
      setSgrade ( rs.getString ( "sGrade" )) ;
      }
      /*关闭
      getCon().close();
        stm.close();
        stm = null;
      rs.close();
      rs = null;
*/         
      }
      else if ( check== 2 ){
        while ( rs.next ()){
        setPwd ( rs.getString ( "pwd" )) ;
        setUsn ( rs.getString ( "usn" )) ;
      }
      }
    }
   
    public int DBUpdate (){
   
      try {
      //Statement stm = null;
      stm = getCon () .createStatement () ;
      String sq = "update stu set sName = '" +getSName () + "',ssex = '" +getSsex () + "',sGrade = '" +getSgrade () + "'where sno ='" +getSno () + "'" ;
      i = stm.executeUpdate ( sq ) ;
      //UPDATE Store_Information SET Sales = 500 WHERE store_name = "Los Angeles"  AND Date = "Jan-08-1999"
      //关闭
      getCon () .close () ;
      stm.close () ;
      stm = null ;
    } catch ( SQLException ex ) {
      Logger.getLogger ( DB. class .getName ()) .log ( Level.SEVERE, null, ex ) ;
    }
    return i;
    }
    public int DBdelete (){
    //Statement stm = null;
    try {
      getCon () .createStatement () ;
      String dsql= "DELETE FROM stu WHERE sno = '" +getSno () + "'" ;
      //DELETE FROM Store_Information WHERE store_name = "Los Angeles"
      //娘啊，user里的表忘删除了……晕……2009.6.4 18：50 铭记！
      stm.executeUpdate ( "delete from user where usn = '" +getSno () + "'" ) ;
      i = stm.executeUpdate ( dsql ) ;
      //关闭
      getCon () .close () ;
      stm.close () ;
      stm = null ;
    } catch ( SQLException ex ) {
      ex.printStackTrace () ;
    }
    return i;
    }
  /**
   * @return the QSql
   */
  public String getQSql () {
    return QSql;
  }

  /**
   * @param QSql the QSql to set
   */
  public void setQSql ( String QSql ) {
    this .QSql = QSql;
  }

  /**
   * @return the usn
   */
  public String getUsn () {
    return usn;
  }

  /**
   * @param usn the usn to set
   */
  public void setUsn ( String usn ) {
    this .usn = usn;
  }

  /**
   * @return the pwd
   */
  public String getPwd () {
    return pwd;
  }

  /**
   * @param pwd the pwd to set
   */
  public void setPwd ( String pwd ) {
    this .pwd = pwd;
  }
}

完整NetBeans项目代码：
http://www.blogjava.net/chenglu//Files/chenglu/Student_NetBeana_Src.zip