updatedbframe.java

《Java实例入门》所有实例的源代码。所有的源文件都是.java文件

import java.net.URL;
import java.sql.*;
import java.util.Vector;
import java.awt.*;
import java.awt.event.*;

public class UpdateDBFrame extends Frame
  implements ActionListener{
  Vector fields;
  Button first,previous,next,last,insert,update,delete,commite,cancel,quit;
  Panel dataView,commandPanel,pUp,pDown;
  Connection con;
  Statement stm;
  ResultSet rs;
  boolean isInsert;
  public UpdateDBFrame() {
     setTitle("数据库更新");
     setSize(400,400);
     setBackground(Color.lightGray);
     addWindowListener(new WindowAdapter(){
                   public void windowClosing(WindowEvent e){
                           System.exit(0);
                    }
                                            }
                        );
     dataView=new Panel();
     commandPanel=new Panel();
     add("Center",dataView);
     dataView.setLayout(new GridBagLayout());
     setButton();
     add("South",commandPanel);

     fields=new Vector();
     openTable();
     loadField();
     loadData();
     isInsert=true;
     pack();
  }
  private void setButton(){
     commandPanel.setLayout(new GridLayout(2,1));
     pUp=new Panel();
     first=new Button("First");
     first.addActionListener(this);
     previous=new Button("Previous");
     previous.addActionListener(this);
     next=new Button("Next");
     next.addActionListener(this);
     last=new Button("Last");
     last.addActionListener(this);
     first.setEnabled(false);
     previous.setEnabled(false);
     pUp.add(first);
     pUp.add(previous);
     pUp.add(next);
     pUp.add(last);
     insert=new Button("Insert");
     insert.addActionListener(this);
     update=new Button("Update");
     update.addActionListener(this);
     delete=new Button("Delete");
     delete.addActionListener(this);
     commite=new Button("Commite");
     commite.addActionListener(this);
     cancel=new Button("Cancel");
     cancel.addActionListener(this);
     quit=new Button("Quit");
     commite.setEnabled(false);
     cancel.setEnabled(false);
     pDown=new Panel();
     pDown.add(insert);
     pDown.add(update);
     pDown.add(delete);
     pDown.add(commite);
     pDown.add(cancel);
     pDown.add(quit);
     commandPanel.add(pUp);
     commandPanel.add(pDown);
     quit.addActionListener(new ActionListener(){
                        public  void actionPerformed(ActionEvent evt){
                                   System.exit(0);
                          }
                                                }
                           );
  }
  public void openTable(){
     try{
          Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
          con=DriverManager.getConnection("jdbc:odbc:JDBCTEST;pwd=java");
          stm=con.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,ResultSet.CONCUR_UPDATABLE);
          rs=stm.executeQuery("select * from publishers");
          rs.first();
     }catch(Exception e){
          return;
     }
  }
   public void loadField(){
     GridBagConstraints gbc=new GridBagConstraints();
     gbc.weighty=100;
     try{
         ResultSetMetaData rsmd=rs.getMetaData();
        for(int i=1;i<=rsmd.getColumnCount() ;i++){
             String fieldName=rsmd.getColumnName(i);
            int  fieldSize=rsmd.getColumnDisplaySize(i) ;
             TextField txtField=new TextField();
             txtField.setEditable(false) ;
             fields.add(txtField);
             gbc.weightx=0;
             gbc.anchor=GridBagConstraints.EAST;
             gbc.fill=GridBagConstraints.NONE;
             gbc.gridx=0;
             gbc.gridy=i-1;
             gbc.gridwidth=1;
             gbc.gridheight=1;
             dataView.add(new Label(fieldName),gbc);

             gbc.weightx=100;
             gbc.anchor=GridBagConstraints.WEST;
             gbc.fill=GridBagConstraints.HORIZONTAL;
             gbc.gridx=1;
             dataView.add(txtField,gbc);
         }
     }catch(Exception e){
          return;
     }
   }
     public void loadData(){
     try{
          ResultSetMetaData rsmd=rs.getMetaData();
         for(int i=1;i<=fields.size() ;i++){
             String value="";
             String name=rsmd.getColumnName(i).trim();
             value=rs.getString(name);
             TextField txtField=(TextField)fields.get(i-1);
             txtField.setText(value);
          }
     }catch(Exception e){
          System.out.println(e);
     }
  }
   public void actionPerformed(ActionEvent e){
       Object obj = e.getSource();
      if(obj==first) showfirst();
      if(obj==previous) showprevious();
      if(obj==next) shownext();
      if(obj==last) showlast();
      if(obj==insert) insertData();
      if(obj==update) updateData();
      if(obj==delete) delData();
      if(obj==commite) commiteData();
      if(obj==cancel) cancelCommand();
   }
   private void showfirst(){
       try{
            rs.first();
            loadData();
            enableButtons();
       }catch(Exception e){
       }
   }
   private void showprevious(){
       try{
            rs.previous();
            loadData();
            enableButtons();
       }catch(Exception e){
       }
   }
   private void shownext(){
       try{
            rs.next();
            loadData();
            enableButtons();
       }catch(Exception e){
       }
   }
   private void showlast(){
       try{
            rs.last();
            loadData();
            enableButtons();
       }catch(Exception e){
       }
   }
   private void  insertData(){
        isInsert=true;
        pUp.setVisible(false);
        update.setEnabled(false);
        delete.setEnabled(false);
        commite.setEnabled(true);
        cancel.setEnabled(true);
       for(int i=1;i<=fields.size() ;i++){
             TextField txtField=(TextField)fields.get(i-1);
             txtField.setText("");
             txtField.setEditable(true);
        }
        insert.setEnabled(false);
        try{
          //  rs.moveToInsertRow();
       }catch(Exception e){
             System.out.println(e);
       }

   }
   private void  updateData(){
        isInsert=false;
        pUp.setVisible(false);
        insert.setEnabled(false);
        update.setEnabled(false);
        delete.setEnabled(false);
        commite.setEnabled(true);
        cancel.setEnabled(true);
       for(int i=1;i<=fields.size() ;i++){
             TextField txtField=(TextField)fields.get(i-1);
             txtField.setEditable(true);
        }
        try{
          //  rs.moveToInsertRow();
       }catch(Exception e){
             System.out.println(e);
       }

   }
   private void  commiteData(){
    try{
        ResultSetMetaData rsmd=rs.getMetaData();
       for(int i=1;i<=fields.size() ;i++){
             TextField txtField=(TextField)fields.get(i-1);
             String value=txtField.getText().trim();
             String name=rsmd.getColumnName(i).trim().toUpperCase();
             rs.updateString(name,value );
             txtField.setEditable(false);
        }
         String value;
      if (isInsert)
            rs.insertRow() ;
      else
            rs.updateRow();
      rs.moveToCurrentRow();
      pUp.setVisible(true);
      insert.setEnabled(true);
      update.setEnabled(true);
      delete.setEnabled(true);
      commite.setEnabled(false);
      cancel.setEnabled(false);
      rs.refreshRow();
      loadData();
      enableButtons();
    }catch(SQLException e){
       System.out.println(e);
    }
   }
   private void  cancelCommand(){
      try{
           for(int i=1;i<=fields.size() ;i++){
               TextField txtField=(TextField)fields.get(i-1);
               txtField.setEditable(false);
            }
           rs.moveToCurrentRow();
           rs.refreshRow();
           pUp.setVisible(true);
           insert.setEnabled(true);
           update.setEnabled(true);
           delete.setEnabled(true);
           commite.setEnabled(false);
           cancel.setEnabled(false);
           loadData();
           enableButtons();
       }catch(Exception e){
             System.out.println(e);
       }
   }
   private void  delData(){
      try{
           int CursorPos=rs.getRow();
            rs.deleteRow();
            rs.absolute(CursorPos-1);
            loadData();
            enableButtons();
       }catch(Exception e){
       }
   }
   private void enableButtons(){
       try{
            first.setEnabled(!rs.isFirst());
            previous.setEnabled(!rs.isFirst());
            next.setEnabled(!rs.isLast());
            last.setEnabled(!rs.isLast());
       }catch(Exception e){
       }
   }
   static public void  main(String[] args){
      UpdateDBFrame db=new  UpdateDBFrame();
      db.show();
   }
}