import java.awt.*;import java.awt.event.*;import java.sql.*;import javax.swing.*;import javax.swing.border.EmptyBorder;public class databd extends JFrame implements ActionListener{    static frameDemo a=null;  String getuser="";  String getpd="";  String sql = "select * from dl where id='";  String sql1 = "select password from dl where password='";  JButton btnNewButton = new JButton("登錄");  JButton btnNewButton_1 = new JButton("注冊");   JTextField show=new JTextField("/t  請選擇按鈕",10);    private JPanel contentPane;  private JTextField userField;  private JPasswordField pwdField;  private Statement statement = null; //查詢賬號  private Statement statement2 = null; //注冊賬戶    private static databd frame;      //  ResultSet rst2=null;  public static void main(String[] args) {    EventQueue.invokeLater(new Runnable() {      public void run() {        try {          frame = new databd();          frame.setVisible(true);        } catch (Exception e) {          e.printStackTrace();        }      }    });  }  public databd() {    String driver = "com.mysql.jdbc.Driver";       String url = "jdbc:mysql://localhost:8088/library?useUnicode=true&characterEncoding=utf-8&useSSL=false";     String user = "root";            String password = "11111";    try{    Class.forName(driver);        Connection conn = DriverManager.getConnection(url, user, password);    Connection conn2 = DriverManager.getConnection(url, user, password);    statement = conn.createStatement();    statement2 = conn2.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,ResultSet.CONCUR_UPDATABLE);    rst2=statement2.executeQuery("select * from dl");    show.setEditable(false);    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);    setSize(250, 200);           setLocationRelativeTo(null);      contentPane = new JPanel();    contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));    contentPane.setLayout(null);    add(contentPane);    JLabel lblUsername = new JLabel("賬號");    lblUsername.setBounds(12, 13, 54, 15);    contentPane.add(lblUsername);    JLabel lblPassword = new JLabel("密碼");    lblPassword.setBounds(12, 38, 54, 15);    contentPane.add(lblPassword);    userField = new JTextField();    userField.setBounds(76, 10, 144, 21);    contentPane.add(userField);    userField.setColumns(10);    pwdField = new JPasswordField();    pwdField.setEchoChar('*');  //密碼回顯字符    pwdField.setBounds(76, 35, 144, 21);    contentPane.add(pwdField);    pwdField.setColumns(10);    add(show,BorderLayout.SOUTH);    btnNewButton.addActionListener(this); //登錄    btnNewButton.setBounds(10, 92, 93, 23);    contentPane.add(btnNewButton);    btnNewButton_1.addActionListener(this); //注冊    btnNewButton_1.setBounds(127, 92, 93, 23);    contentPane.add(btnNewButton_1);    show.addActionListener(this);    }catch(ClassNotFoundException e){System.out.print("不能找到驅動器");    }catch(Exception e){System.out.print("出現錯誤");e.printStackTrace();}    }   public void actionPerformed(ActionEvent e) {    getuser=userField.getText().trim()+"'";    String pd=String.valueOf(pwdField.getPassword());    try{              ResultSet rs=statement.executeQuery(sql+getuser);      if(e.getSource()==btnNewButton){ //登錄         if(rs.next()){                    if(rs.getString(2).equals(pd)){            frame.setVisible(false);            JOptionPane.showMessageDialog(null, "登錄成功");            UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());            a=frameDemo.a; //生成靜態對象            }else show.setText("/t  密碼錯誤");          }          else           show.setText("/t  賬號不存在");        }      else if(e.getSource()==btnNewButton_1){ //注冊          if(userField.getText().equals("")){            show.setText("/t 注冊賬號不能為空");}          else {            if((String.valueOf(pwdField.getPassword())).equals(""))              show.setText("/t 注冊密碼不能為空");            else {register();}            }      }    }catch(Exception c){c.printStackTrace();}            }   private void register(){       String name=userField.getText(),         passwd=String.valueOf(pwdField.getPassword());     try{     rst2.moveToInsertRow();     rst2.updateString(1, name);     rst2.updateString(2, passwd);     rst2.insertRow();     rst2.moveToCurrentRow();     show.setText("/t  注冊成功");     }catch(Exception e){show.setText("/t  注冊失敗");}   }}

package database;import javax.swing.*;import javax.swing.border.TitledBorder;import java.awt.*;import java.awt.event.*;import java.sql.*;import java.util.Calendar;import java.util.GregorianCalendar;public class frameDemo extends JFrame implements ActionListener{  public static frameDemo a=new frameDemo();   JPanel panel=new JPanel(),      panel1=new JPanel(),      panel2=new JPanel(),      panel3=new JPanel(),      panel4=new JPanel(),      panel5=new JPanel();  String[] adds={"請選擇操作","添加館藏記錄","添加借書記錄","添加學生記錄"};  String[] deletes={"請選擇操作","刪除館藏記錄","刪除借書記錄","刪除學生記錄"};  String[] changes={"請選擇操作","修改庫存記錄","修改應還日期"};  String[] querys={"請選擇操作","查詢書籍","查詢書號","查詢學生借書記錄","查詢學生信息"};  String[] shows={"請選擇操作","顯示所有館藏記錄","顯示借書記錄","顯示學生記錄"};  String[] record=new String[4];  JTextArea ta=new JTextArea("-->歡迎使用系統/n",11,60);  JScrollPane pane=new JScrollPane(ta);  Connection conn=null;  Statement stmt=null;  Statement stmt1=null;  Statement stmt2=null;  ResultSet rst=null;  ResultSet rst1=null;  ResultSet rst2=null;  static boolean key;  private JFrame big=new JFrame("請選擇操作");  private JComboBox add=new JComboBox(adds);  private JComboBox delete=new JComboBox(deletes);  private JComboBox change=new JComboBox(changes);  private JComboBox query=new JComboBox(querys);  private JComboBox show=new JComboBox(shows);  public frameDemo(){    super("圖書館管理系統");    try{      Class.forName("com.mysql.jdbc.Driver");      String url="jdbc:mysql://localhost:8088/library?useUnicode=true&characterEncoding=utf-8&useSSL=false";      String user="root";      String password="11111";      conn=DriverManager.getConnection(url, user, password);           panel4.setLayout(new GridLayout(3,1,30,10));      panel4.setBorder(new TitledBorder("選擇管理:"));      panel1.add(new JLabel("添加記錄:"));      panel1.add(add);      panel1.add(new JLabel("刪除記錄:"));      panel1.add(delete);      panel2.add(new JLabel("修改記錄:"));      panel2.add(change);      panel2.add(new JLabel("查詢記錄:"));      panel2.add(query);      panel3.add(new JLabel("顯示記錄:"));      panel3.add(show);      panel4.add(panel1);panel4.add(panel2);panel4.add(panel3);          panel5.add(pane);      panel.add(panel5,BorderLayout.SOUTH);      panel.add(panel4,BorderLayout.CENTER);       add(panel);      //pack();      stmt=conn.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,ResultSet.CONCUR_UPDATABLE);//可滾可更            stmt1=conn.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,ResultSet.CONCUR_UPDATABLE);           stmt2=conn.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,ResultSet.CONCUR_UPDATABLE);      add.addActionListener(this);      delete.addActionListener(this);      change.addActionListener(this);      query.addActionListener(this);      show.addActionListener(this);      setSize(470,440);      //setResizable(false);      setLocationRelativeTo(null);      setVisible(true);      setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);      }catch(Exception e){e.printStackTrace();}  }  public void actionPerformed(ActionEvent ae){    try{      //if(key){   //數據庫非空       if(add.getSelectedIndex()==1){                 ta.append("-->添加館藏記錄/n");        addinformation a1=new addinformation("圖書編號", "書名", "庫存",1);              }       else if(add.getSelectedIndex()==2){        ta.append("-->添加借書記錄/n");        addinformation a1=new addinformation("圖書編號", "學號",2);       }       else if(add.getSelectedIndex()==3){         ta.append("-->添加學生記錄/n");         addinformation a1=new addinformation("學生學號", "學生姓名",3);       }       add.setSelectedItem("請選擇操作");       if(delete.getSelectedIndex()==1){        ta.append("-->刪除館藏記錄/n");        addinformation a1=new addinformation("圖書編號",4);       }       else if(delete.getSelectedIndex()==2){         ta.append("-->刪除借書記錄/n");         addinformation a1=new addinformation("圖書編號","學生學號",5);       }       else if(delete.getSelectedIndex()==3){        ta.append("-->刪除學生記錄/n");        addinformation a1=new addinformation("學生學號",6);       }       delete.setSelectedItem("請選擇操作");       if(change.getSelectedIndex()==1){        ta.append("-->修改庫存記錄/n");        addinformation a1=new addinformation("圖書編號","庫存數目",7);       }       else if(change.getSelectedIndex()==2){        ta.append("-->修改應還日期/n");        addinformation a1=new addinformation("圖書編號","學生學號","應還日期",8);         }       change.setSelectedItem("請選擇操作");       if(query.getSelectedIndex()==1){        ta.append("-->按書名查詢/n");        addinformation a1=new addinformation("書名",9);         }       else if(query.getSelectedIndex()==2){        ta.append("-->按書籍編號查詢/n");        addinformation a1=new addinformation("書籍編號",10);       }       else if(query.getSelectedIndex()==3){        ta.append("-->查詢學生借書記錄/n");        addinformation a1=new addinformation("學生學號",11);       }       else if(query.getSelectedIndex()==4){        ta.append("-->查詢學生信息/n");        addinformation a1=new addinformation("學生學號",12);         }       query.setSelectedItem("請選擇操作");       if(show.getSelectedIndex()==1){         ta.append("-->顯示所有館藏記錄/n");         try{          rst=stmt.executeQuery("SELECT * FROM book");          rst.first();          ta.append("------------------------------------/n");          int id=rst.getInt(1);          String name=rst.getString(2);          int num=rst.getInt(3);           ta.append("/t書籍編號/t書籍名稱/t在館庫存/n");          ta.append("/t"+id+"/t"+name+"/t"+num+"/n");          while(rst.next()){              id=rst.getInt(1);              name=rst.getString(2);              num=rst.getInt(3);              ta.append("/t"+id+"/t"+name+"/t"+num+"/n");            }//執行后游標指向最后一行的后一個位置            rst.first();            ta.append("------------------------------------/n");          }catch(Exception e){ta.append("-->顯示錯誤");}       }       else if(show.getSelectedIndex()==2){         ta.append("-->顯示借書記錄/n");                 rst1=stmt1.executeQuery("SELECT * FROM bs");         Calendar calendar =new GregorianCalendar();         try{          rst1.first();          ta.append("----------------------------------------------------/n");          int bookid=rst1.getInt(2);          int stdid=rst1.getInt(3);          Date x=rst1.getDate(4);                calendar.setTime(x);           calendar.add(calendar.DATE, 30);           java.util.Date utilDate = (java.util.Date)calendar.getTime();           utilDate = (java.util.Date)calendar.getTime();           Date newDate =new Date(utilDate.getTime());            ta.append("/t書籍編號/t學生學號/t借書日期/t/t應還日期/n");          ta.append("/t"+bookid+"/t"+stdid+"/t"+x+"/t"+newDate+"/n");                 while(rst1.next()){              bookid=rst1.getInt(2);              stdid=rst1.getInt(3);              x=rst1.getDate(4);              calendar.setTime(x);              calendar.add(calendar.DATE, 30);              utilDate = (java.util.Date)calendar.getTime();              utilDate = (java.util.Date)calendar.getTime();              newDate =new Date(utilDate.getTime());              ta.append("/t"+bookid+"/t"+stdid+"/t"+x+"/t"+newDate+"/n");            }//執行后游標指向最后一行的后一個位置            rst1.first();            ta.append("----------------------------------------------------/n");          }catch(Exception e){ta.append("-->顯示錯誤");e.printStackTrace();}       }       else if(show.getSelectedIndex()==3){         ta.append("-->顯示學生記錄/n");         try{          rst2=stmt2.executeQuery("SELECT * FROM std");          rst2.first();          ta.append("------------------------------------/n");          int id=rst2.getInt(1);          String name=rst2.getString(2);          ta.append("/t學生學號/t學生姓名/n");          ta.append("/t"+id+"/t"+name+"/t"+"/n");          while(rst2.next()){              id=rst2.getInt(1);              name=rst2.getString(2);              ta.append("/t"+id+"/t"+name+"/t"+"/n");            }//執行后游標指向最后一行的后一個位置          rst2.first();          ta.append("------------------------------------/n");          }catch(Exception e){ta.append("-->顯示錯誤");}       }       show.setSelectedItem("請選擇操作");       ta.setCaretPosition(ta.getText().length()); //滾動條保持在最后一條         }catch(Exception e){e.printStackTrace();}   }  public void showMessage(){    try{      int a=rst.getRow();      ta.append(a+"/n");      rst.first();      ta.append("---------------------------/n");      String id=rst.getString(1),          name=rst.getString(2),          brand=rst.getString(3),          price=rst.getString(4),          stock=rst.getString(5);           ta.append(id+" "+name+" "+brand+" "+price+" "+stock+"/n");      while(rst.next()){        id=rst.getString(1);        name=rst.getString(2);        brand=rst.getString(3);        price=rst.getString(4);        stock=rst.getString(5);        ta.append(id+" "+name+" "+brand+" "+price+" "+stock+"/n");      }//執行后游標指向最后一行的后一個位置      rst.absolute(a);      ta.append("---------------------------/n");    }catch(Exception e){ta.append("-->顯示錯誤");}  }// public static void main(String[] args){   //       try{//UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());     //       }catch(Exception e){System.out.print("1111111111");}//       a=new frameDemo();//     }  }

package database;import javax.swing.*;import java.util.Calendar;import java.util.GregorianCalendar;import java.awt.*;import java.awt.event.*;import java.sql.*;public class addinformation extends JFrame implements ActionListener{  JButton sure=new JButton("確定"),      quxiao=new JButton("取消");  JTextField jtf1=new JTextField(10),      jtf2=new JTextField(10),      jtf3=new JTextField(10);  Connection conn=null;  static{    try{    Class.forName("com.mysql.jdbc.Driver");    }catch(Exception e){e.printStackTrace();}      }  int x=0;  public Connection getConnection() throws SQLException{    if(conn==null){      conn=DriverManager.getConnection("jdbc:mysql://localhost:8088/library?useUnicode=true&characterEncoding=utf-8&useSSL=false","root","11111");    }    return conn;  }  addinformation(String s1,String s2,String s3,int m){    JPanel p=new JPanel();    p.setLayout(new FlowLayout());     p.add(new JLabel(s1));    p.add(jtf1);    p.add(new JLabel(s2));    p.add(jtf2);    p.add(new JLabel(s3));    p.add(jtf3);      p.add(sure);    p.add(quxiao);    add(p);    if(m==8){      JOptionPane.showMessageDialog(null, "圖書日期應為 XXXX-XX-XX 格式！","警告",JOptionPane.WARNING_MESSAGE);    }    setSize(500, 100);     setVisible(true);     setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);           setLocationRelativeTo(null);     sure.addActionListener(this);    quxiao.addActionListener(this);    x=m;  }  addinformation(String s1,String s2,int m){       JPanel p=new JPanel();    p.setLayout(new FlowLayout());     p.add(new JLabel(s1));    p.add(jtf1);    p.add(new JLabel(s2));    p.add(jtf2);      p.add(sure);    p.add(quxiao);    add(p);    setSize(500, 100);     setVisible(true);     setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);           setLocationRelativeTo(null);     sure.addActionListener(this);    quxiao.addActionListener(this);    x=m;  }  addinformation(String s1,int m){    JPanel p=new JPanel();    p.setLayout(new FlowLayout());     p.add(new JLabel(s1));    p.add(jtf1);    if(m==4){    JOptionPane.showMessageDialog(null, "若存在借閱記錄則不能刪除書籍信息！","警告",JOptionPane.WARNING_MESSAGE);    }    if(m==6){    JOptionPane.showMessageDialog(null, "若學生存在借閱記錄則不能刪除該學生信息！","警告",JOptionPane.WARNING_MESSAGE);    }    p.add(sure);    p.add(quxiao);    add(p);     setSize(500, 80);     setVisible(true);     setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);           setLocationRelativeTo(null);     sure.addActionListener(this);    quxiao.addActionListener(this);    x=m;  }  public void actionPerformed(ActionEvent ae){    if(ae.getSource()==sure){      if(x==1){  //添加 館藏記錄        String sql="INSERT INTO book VALUES(?,?,?)";        try(          Connection conn=getConnection();        PreparedStatement stmt=conn.prepareStatement(sql)){        int id=Integer.parseInt(jtf1.getText());        String name=jtf2.getText();        int num=Integer.parseInt(jtf3.getText());        stmt.setInt(1, id);        stmt.setString(2, name);        stmt.setInt(3, num);        stmt.executeUpdate();        frameDemo.a.ta.append("-->添加成功/n");              }catch(Exception x){frameDemo.a.ta.append("-->插入出錯/n");x.printStackTrace();}        addinformation.this.dispose();       }      if(x==2){  //添加借書記錄          String sql="INSERT INTO bs(bookid,stdid,date) VALUES(?,?,?)";          String sql1="SELECT id,num FROM book WHERE id=?";          String sql2="SELECT id FROM std WHERE id=?";          try{          Connection conn1=getConnection();          PreparedStatement stmt1=conn1.prepareStatement(sql1,ResultSet.TYPE_SCROLL_SENSITIVE,ResultSet.CONCUR_UPDATABLE);          stmt1.setInt(1,Integer.parseInt(jtf1.getText()));                    ResultSet rst1=stmt1.executeQuery();//找有沒有這本書和庫存是否為0          if(rst1.next()&&(rst1.getInt(2)>0)){            int n=rst1.getInt(2);n-=1;            int m=rst1.getInt(1);            rst1.updateInt(1, m);            rst1.updateInt(2, n);            rst1.updateRow();            Connection conn2=getConnection();            PreparedStatement stmt2=conn2.prepareStatement(sql2);            stmt2.setInt(1,Integer.parseInt(jtf2.getText()));            ResultSet rst2=stmt2.executeQuery();//有人            if(rst2.next()){              Connection conn=getConnection();              PreparedStatement stmt=conn.prepareStatement(sql);              int bookid=Integer.parseInt(jtf1.getText());              int stdid=Integer.parseInt(jtf2.getText());               stmt.setInt(1, bookid);              stmt.setInt(2, stdid);              stmt.setDate(3, new Date(System.currentTimeMillis()));              stmt.executeUpdate();              frameDemo.a.ta.append("-->添加成功/n");            }            else{frameDemo.a.ta.append("-->無該學生記錄，不能添加借閱記錄/n");}          }else{frameDemo.a.ta.append("-->無此書或已全部借出/n");}                        }catch(Exception x){frameDemo.a.ta.append("-->插入出錯/n");x.printStackTrace();}          addinformation.this.dispose();              }      if(x==3){  //添加學生記錄        String sql="INSERT INTO std VALUES(?,?)";        try(          Connection conn=getConnection();        PreparedStatement stmt=conn.prepareStatement(sql)){        int id=Integer.parseInt(jtf1.getText());        String name=jtf2.getText();         stmt.setInt(1, id);        stmt.setString(2, name);        stmt.executeUpdate();        frameDemo.a.ta.append("-->添加成功/n");            }catch(Exception x){frameDemo.a.ta.append("-->插入出錯/n");x.printStackTrace();}        addinformation.this.dispose();             }      if(x==4){  //刪除圖書記錄        String sql="DELETE FROM book WHERE id=?";        String sql1="SELECT * FROM bs WHERE bookid=?";        try{        Connection conn1=getConnection();        PreparedStatement stmt1=conn1.prepareStatement(sql1);        stmt1.setInt(1,Integer.parseInt(jtf1.getText()));        ResultSet rst1=stmt1.executeQuery();        if(rst1.next()){  //借閱記錄中有書          JOptionPane.showMessageDialog(null, "借閱記錄中有該書的借閱記錄！","警告",JOptionPane.WARNING_MESSAGE);        }        else{    //借閱記錄無書，可以刪掉          Connection conn=getConnection();          PreparedStatement stmt=conn.prepareStatement(sql);          int id=Integer.parseInt(jtf1.getText());          stmt.setInt(1, id);          int t=stmt.executeUpdate();          if(t==0){          frameDemo.a.ta.append("-->刪除出錯/n");          JOptionPane.showMessageDialog(null, "不存在該圖書信息！","警告",JOptionPane.WARNING_MESSAGE);          }          else frameDemo.a.ta.append("-->刪除記錄成功/n");         }                  }catch(Exception x){frameDemo.a.ta.append("-->刪除失敗/n");x.printStackTrace();}        addinformation.this.dispose();      }      if(x==5){  //刪除借書記錄        String sql="DELETE FROM bs WHERE bookid=? AND stdid=?";        String sql1="SELECT id,num FROM book WHERE id=?";        try{              Connection conn=getConnection();        PreparedStatement stmt=conn.prepareStatement(sql);        int bookid=Integer.parseInt(jtf1.getText());        int stdid=Integer.parseInt(jtf2.getText());        stmt.setInt(1, bookid);        stmt.setInt(2, stdid);        int t=stmt.executeUpdate();        if(t!=0){          Connection conn1=getConnection();          PreparedStatement stmt1=conn1.prepareStatement(sql1,ResultSet.TYPE_SCROLL_SENSITIVE,ResultSet.CONCUR_UPDATABLE);          stmt1.setInt(1,Integer.parseInt(jtf1.getText()));            ResultSet rst1=stmt1.executeQuery();rst1.next();          int m=rst1.getInt(1);          int n=rst1.getInt(2);n+=1;          rst1.updateInt(1, m);          rst1.updateInt(2, n);          rst1.updateRow();          frameDemo.a.ta.append("-->刪除借閱記錄成功/n");        }        else{          frameDemo.a.ta.append("-->刪除出錯/n");          JOptionPane.showMessageDialog(null, "不存在這條借閱記錄！","警告",JOptionPane.WARNING_MESSAGE);        }                   }catch(Exception x){frameDemo.a.ta.append("-->刪除出錯/n");x.printStackTrace();}        addinformation.this.dispose();      }      if(x==6){ //刪除學生記錄        String sql="DELETE FROM std WHERE id=?";        String sql1="SELECT * FROM bs WHERE stdid=?";        try {          Connection conn1=getConnection();          PreparedStatement stmt1=conn1.prepareStatement(sql1);          stmt1.setInt(1,Integer.parseInt(jtf1.getText()));          ResultSet rst1=stmt1.executeQuery();          if(rst1.next()){  //借閱記錄中有該人            JOptionPane.showMessageDialog(null, "借閱記錄中有該人的借閱記錄！","警告",JOptionPane.WARNING_MESSAGE);          }          else{            Connection conn=getConnection();            PreparedStatement stmt=conn.prepareStatement(sql);            int stdid=Integer.parseInt(jtf1.getText());            stmt.setInt(1, stdid);            int t=stmt.executeUpdate();            if(t==0){              frameDemo.a.ta.append("-->刪除出錯/n");              JOptionPane.showMessageDialog(null, "不存在該學生記錄！","警告",JOptionPane.WARNING_MESSAGE);              }            else frameDemo.a.ta.append("-->刪除記錄成功/n");            }                     }catch(Exception x){frameDemo.a.ta.append("-->刪除出錯/n");x.printStackTrace();}        addinformation.this.dispose();      }      if(x==7){  //修改圖書庫存記錄        String sql="UPDATE book SET num=? WHERE id=?";        try(          Connection conn=getConnection();        PreparedStatement stmt=conn.prepareStatement(sql)){        int num=Integer.parseInt(jtf2.getText());        int bookid=Integer.parseInt(jtf1.getText());        stmt.setInt(1, num);        stmt.setInt(2, bookid);        int t=stmt.executeUpdate();        if(t==0){          frameDemo.a.ta.append("-->修改出錯/n");          JOptionPane.showMessageDialog(null, "不存在該圖書記錄！","警告",JOptionPane.WARNING_MESSAGE);        }        else frameDemo.a.ta.append("-->修改記錄成功/n");            }catch(Exception x){frameDemo.a.ta.append("-->修改出錯/n");x.printStackTrace();}        addinformation.this.dispose();      }      if(x==8){  //修改應還日期        String sql="UPDATE bs SET date=? WHERE bookid=? AND stdid=?";        try(          Connection conn=getConnection();        PreparedStatement stmt=conn.prepareStatement(sql)){        Date date = Date.valueOf(jtf3.getText());        Calendar calendar =new GregorianCalendar();        calendar.setTime(date);        calendar.add(calendar.DATE, -30);        java.util.Date utilDate = (java.util.Date)calendar.getTime();        utilDate = (java.util.Date)calendar.getTime();        Date newDate =new Date(utilDate.getTime());        int stdid=Integer.parseInt(jtf2.getText());        int bookid=Integer.parseInt(jtf1.getText());        stmt.setDate(1, newDate);                stmt.setInt(2, bookid);        stmt.setInt(3, stdid);        int t=stmt.executeUpdate();        if(t==0){          frameDemo.a.ta.append("-->修改出錯/n");          JOptionPane.showMessageDialog(null, "不存在該借書記錄！","警告",JOptionPane.WARNING_MESSAGE);        }        else frameDemo.a.ta.append("-->修改記錄成功/n");            }catch(Exception x){frameDemo.a.ta.append("-->修改出錯/n");x.printStackTrace();}        addinformation.this.dispose();      }      if(x==9){  //按書名查詢        String sql="SELECT * from book WHERE name=?";        ResultSet rst=null;        try(          Connection conn=getConnection();        PreparedStatement stmt=conn.prepareStatement(sql)){        String name=jtf1.getText();        stmt.setString(1, name);                rst=stmt.executeQuery();        if(rst.next()){          frameDemo.a.ta.append("---------------------------------------/n");          frameDemo.a.ta.append("/t圖書編號/t書名/t在館數/n");          frameDemo.a.ta.append("/t"+rst.getInt(1)+"/t"+rst.getString(2)+"/t"+rst.getInt(3)+"/n");          frameDemo.a.ta.append("---------------------------------------/n");        }        else{          frameDemo.a.ta.append("-->查詢出錯/n");          JOptionPane.showMessageDialog(null, "不存在該書！","警告",JOptionPane.WARNING_MESSAGE);          }        }catch(Exception x){frameDemo.a.ta.append("-->查詢出錯/n");x.printStackTrace();}        addinformation.this.dispose();      }        if(x==10){  //按書籍編號查詢        String sql="SELECT * from book WHERE id=?";        ResultSet rst=null;        try(          Connection conn=getConnection();        PreparedStatement stmt=conn.prepareStatement(sql)){        stmt.setInt(1, Integer.parseInt(jtf1.getText()));                rst=stmt.executeQuery();        if(rst.next()){          frameDemo.a.ta.append("---------------------------------------/n");          frameDemo.a.ta.append("/t圖書編號/t書名/t在館數/n");          frameDemo.a.ta.append("/t"+rst.getInt(1)+"/t"+rst.getString(2)+"/t"+rst.getInt(3)+"/n");          frameDemo.a.ta.append("---------------------------------------/n");        }        else{          frameDemo.a.ta.append("-->查詢出錯/n");          JOptionPane.showMessageDialog(null, "不存在該書！","警告",JOptionPane.WARNING_MESSAGE);          }        }catch(Exception x){frameDemo.a.ta.append("-->查詢出錯/n");x.printStackTrace();}        addinformation.this.dispose();      }      if(x==11){  //按學生借書記錄查詢        String sql="SELECT bookid,stdid,date from bs WHERE stdid=?";        ResultSet rst=null;        try(          Connection conn=getConnection();        PreparedStatement stmt=conn.prepareStatement(sql)){        stmt.setInt(1, Integer.parseInt(jtf1.getText()));                rst=stmt.executeQuery();        Calendar calendar =new GregorianCalendar();        if(rst.next()){          frameDemo.a.ta.append("----------------------------------------------------/n");          frameDemo.a.ta.append("/t圖書編號/t學生學號/t借書時間/t/t應還時間/n");          Date x=rst.getDate(3);                   calendar.setTime(x);           calendar.add(calendar.DATE, 30);           java.util.Date utilDate = (java.util.Date)calendar.getTime();           utilDate = (java.util.Date)calendar.getTime();           Date newDate =new Date(utilDate.getTime());           frameDemo.a.ta.append("/t"+rst.getInt(1)+"/t"+rst.getInt(2)+"/t"+x+"/t"+newDate+"/n");          while(rst.next()){                  x=rst.getDate(3);           calendar.setTime(x);           calendar.add(calendar.DATE, 30);           utilDate = (java.util.Date)calendar.getTime();           utilDate = (java.util.Date)calendar.getTime();           newDate =new Date(utilDate.getTime());           frameDemo.a.ta.append("/t"+rst.getInt(1)+"/t"+rst.getInt(2)+"/t"+x+"/t"+newDate+"/n");           }           frameDemo.a.ta.append("----------------------------------------------------/n");          }          else{          frameDemo.a.ta.append("-->查詢出錯/n");          JOptionPane.showMessageDialog(null, "不存在該借書記錄！","警告",JOptionPane.WARNING_MESSAGE);           }        }catch(Exception x){frameDemo.a.ta.append("-->查詢出錯/n");x.printStackTrace();}        addinformation.this.dispose();      }      if(x==12){  //查詢學生信息        String sql="SELECT * from std WHERE id=?";        ResultSet rst=null;        try(          Connection conn=getConnection();        PreparedStatement stmt=conn.prepareStatement(sql)){        stmt.setInt(1, Integer.parseInt(jtf1.getText()));                rst=stmt.executeQuery();        if(rst.next()){          frameDemo.a.ta.append("---------------------------------------/n");          frameDemo.a.ta.append("/t學生學號/t學生姓名/t/n");                frameDemo.a.ta.append("/t"+rst.getInt(1)+"/t"+rst.getString(2)+"/n");          frameDemo.a.ta.append("---------------------------------------/n");          }          else{          frameDemo.a.ta.append("-->查詢出錯/n");          JOptionPane.showMessageDialog(null, "不存在該學生！","警告",JOptionPane.WARNING_MESSAGE);            }        }catch(Exception x){frameDemo.a.ta.append("-->查詢出錯/n");x.printStackTrace();}        addinformation.this.dispose();      }    }    if(ae.getSource()==quxiao){      addinformation.this.dispose();      frameDemo.a.ta.append("-->操作取消/n");    }  }}