我正在进行出勤申请。现在，我正在努力建立一个可以容纳学生的桌子，并允许用户将学生标记为缺席/在场。
下面的可编译和可运行代码显示了我当前的JTable。它看起来我想要它，但我不确定如何使复选框可选，以及如何收集复选框的布尔值。在此表中，数据将来自数据库表
student(std_id,Std_name,total_class,present_class,att_status);
我想在表中只显示3列：std_id，std_name和present / absent（jCheckBox）。
如何根据jcheckbox是选中还是取消选中来更改数据库total_class，present_class？我的意思是，如果学生缺席，那么总课程将增加+1，如果学生在场，则总课程将保持相同，而且两者都将+1.means我必须通过total_class（int）和present_class（int）计算出勤率并将其存储在浮动att_status。 我真的不明白。有人能解释一下吗？`package my.stdams;
import java.sql.*;
import java.util.*;
import javax.swing.table.DefaultTableModel;
public class Vatt1 extends javax.swing.JFrame {
static Connection conn;
public Vatt1() {
initComponents();
try {
String userName = "root";
String password = "aditya";
String url = "jdbc:mysql://localhost:3306/sams";
Class.forName("com.mysql.jdbc.Driver").newInstance();
conn = DriverManager.getConnection(url, userName, password);
} catch (Exception e) {
System.out.println("Unable to connect to database.");
}
}
/**
* This method is called from within the constructor to initialize the form.
* WARNING: Do NOT modify this code. The content of this method is always
* regenerated by the Form Editor.
*/
@SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">
private void initComponents() {
entityManager = java.beans.Beans.isDesignTime() ? null : javax.persistence.Persistence.createEntityManagerFactory("sams?zeroDateTimeBehavior=convertToNullPU").createEntityManager();
studentQuery = java.beans.Beans.isDesignTime() ? null : entityManager.createQuery("SELECT s FROM Student s");
studentList = java.beans.Beans.isDesignTime() ? java.util.Collections.emptyList() : studentQuery.getResultList();
studentQuery1 = java.beans.Beans.isDesignTime() ? null : entityManager.createQuery("SELECT s FROM Student s");
studentList1 = java.beans.Beans.isDesignTime() ? java.util.Collections.emptyList() : studentQuery1.getResultList();
jPanel1 = new javax.swing.JPanel();
jScrollPane1 = new javax.swing.JScrollPane();
jTable1 = new javax.swing.JTable();
jComboBox1 = new javax.swing.JComboBox();
jLabel1 = new javax.swing.JLabel();
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
jPanel1.setBackground(new java.awt.Color(0, 204, 204));
jTable1.setModel(new javax.swing.table.DefaultTableModel(
new Object [][] {
{null, null, null},
{null, null, null},
{null, null, null},
{null, null, null},
{null, null, null},
{null, null, null},
{null, null, null},
{null, null, null},
{null, null, null},
{null, null, null},
{null, null, null},
{null, null, null},
{null, null, null},
{null, null, null},
{null, null, null},
{null, null, null},
{null, null, null},
{null, null, null},
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{null, null, null},
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{null, null, null},
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{null, null, null},
{null, null, null},
{null, null, null},
{null, null, null},
{null, null, null},
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{null, null, null},
{null, null, null},
{null, null, null},
{null, null, null},
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{null, null, null},
{null, null, null},
{null, null, null},
{null, null, null},
{null, null, null},
{null, null, null},
{null, null, null},
{null, null, null},
{null, null, null},
{null, null, null},
{null, null, null},
{null, null, null},
{null, null, null},
{null, null, null},
{null, null, null},
{null, null, null},
{null, null, null},
{null, null, null},
{null, null, null},
{null, null, null},
{null, null, null},
{null, null, null},
{null, null, null},
{null, null, null},
{null, null, null},
{null, null, null},
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{null, null, null},
{null, null, null},
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{null, null, null},
{null, null, null},
{null, null, null},
{null, null, null},
{null, null, null}
},
new String [] {
"Enroll NO.", "Name", "Present"
}
) {
Class[] types = new Class [] {
java.lang.Object.class, java.lang.Object.class, java.lang.Boolean.class
};
public Class getColumnClass(int columnIndex) {
return types [columnIndex];
}
});
jTable1.setGridColor(new java.awt.Color(0, 204, 204));
jTable1.setName("Attendance "); // NOI18N
jTable1.setRowSelectionAllowed(false);
jTable1.addMouseListener(new java.awt.event.MouseAdapter() {
public void mouseClicked(java.awt.event.MouseEvent evt) {
jTable1MouseClicked(evt);
}
});
jTable1.addPropertyChangeListener(new java.beans.PropertyChangeListener() {
public void propertyChange(java.beans.PropertyChangeEvent evt) {
jTable1PropertyChange(evt);
}
});
jScrollPane1.setViewportView(jTable1);
jComboBox1.setModel(new javax.swing.DefaultComboBoxModel(new String[] { "1", "2", "3", "4", "5", "6", "7", "8" }));
jComboBox1.setSelectedItem(null);
jComboBox1.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jComboBox1ActionPerformed(evt);
}
});
jLabel1.setText("Sem");
javax.swing.GroupLayout jPanel1Layout = new javax.swing.GroupLayout(jPanel1);
jPanel1.setLayout(jPanel1Layout);
jPanel1Layout.setHorizontalGroup(
jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(jPanel1Layout.createSequentialGroup()
.addContainerGap()
.addComponent(jScrollPane1, javax.swing.GroupLayout.DEFAULT_SIZE, 533, Short.MAX_VALUE)
.addGap(15, 15, 15))
.addGroup(jPanel1Layout.createSequentialGroup()
.addGap(173, 173, 173)
.addComponent(jLabel1)
.addGap(35, 35, 35)
.addComponent(jComboBox1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
);
jPanel1Layout.setVerticalGroup(
jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(javax.swing.GroupLayout.Alignment.TRAILING, jPanel1Layout.createSequentialGroup()
.addContainerGap()
.addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jComboBox1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(jLabel1))
.addGap(18, 18, 18)
.addComponent(jScrollPane1, javax.swing.GroupLayout.DEFAULT_SIZE, 244, Short.MAX_VALUE)
.addContainerGap())
);
javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
getContentPane().setLayout(layout);
layout.setHorizontalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(jPanel1, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(jPanel1, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
);
pack();
}// </editor-fold>
private void jComboBox1ActionPerformed(java.awt.event.ActionEvent evt) {
Vatt1 p = new Vatt1();
String sem = (String) jComboBox1.getSelectedItem();
Vector rows = p.getRecords(sem);
Vector columns = p.getColumns();
DefaultTableModel dm = (DefaultTableModel) jTable1.getModel();
dm.setDataVector(rows, columns);
}
private void jTable1PropertyChange(java.beans.PropertyChangeEvent evt) {
// TODO add your handling code here:
}
private void jTable1MouseClicked(java.awt.event.MouseEvent evt) {
// TODO add your handling code here:
}
public Vector getColumns() {
Vector columns = new Vector();
columns.add("Roll No");
columns.add("Name");
columns.add("Present");
return columns;
}
public Vector getRecords(String sem) {
Vector rows = new Vector();
try {
Statement stmt = conn.createStatement();
String sql = "SELECT std_id,std_name FROM student where sem=" + sem;
ResultSet rs = stmt.executeQuery(sql);
while (rs.next()) {
Vector temp = new Vector();
temp.addElement(rs.getString(1));
temp.addElement(rs.getString(2));
temp.addElement(Boolean.FALSE);
rows.addElement(temp);
}
} catch (Exception e) {
System.out.println(e);
System.out.println("Here One");
return null;
}
return rows;
}
/**
* @param args the command line arguments
*/
public static void main(String args[]) {
/* Set the Nimbus look and feel */
//<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
/* If Nimbus (introduced in Java SE 6) is not available, stay with the default look and feel.
* For details see http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html
*/
try {
for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
if ("Nimbus".equals(info.getName())) {
javax.swing.UIManager.setLookAndFeel(info.getClassName());
break;
}
}
} catch (ClassNotFoundException ex) {
java.util.logging.Logger.getLogger(Vatt1.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (InstantiationException ex) {
java.util.logging.Logger.getLogger(Vatt1.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (IllegalAccessException ex) {
java.util.logging.Logger.getLogger(Vatt1.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (javax.swing.UnsupportedLookAndFeelException ex) {
java.util.logging.Logger.getLogger(Vatt1.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
}
//</editor-fold>
/* Create and display the form */
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
new Vatt1().setVisible(true);
}
});
}
// Variables declaration - do not modify
private javax.persistence.EntityManager entityManager;
private javax.swing.JComboBox jComboBox1;
private javax.swing.JLabel jLabel1;
private javax.swing.JPanel jPanel1;
private javax.swing.JScrollPane jScrollPane1;
private javax.swing.JTable jTable1;
private java.util.List<my.stdams.Student> studentList;
private java.util.List<my.stdams.Student> studentList1;
private javax.persistence.Query studentQuery;
private javax.persistence.Query studentQuery1;
// End of variables declaration
}