本文介绍了没有列名的 DefaultTableModel的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
这个类与我的数据库通信，检索数据并将它们投影到 JTable.我使用了 DefaultTableModel，但列名不会出现.我在另一个类中实例化这个类，我通过 用数据检索表getTable().
This class communicates with my database retrieves data and project them to a JTable.I used the DefaultTableModel but the column names won't appear.I instantiate this class in another class where i retrieve the table with the data through getTable( ).
package jtable;
import javax.swing.*;
import javax.swing.table.*;
import java.sql.*;
public class ControlDatabase
{
private JTable table;
private Statement stmt;
private DefaultTableModel model;
private String all = "SELECT * FROM Players ORDER BY id ASC";
public ControlDatabase( )
{
String dbUsername = "root";
String dbPassword = "*****";
String dbHost = "localhost";
String dbPort = "3306";
String dbName = "oop_project_database";
String url = "jdbc:mysql://" + dbHost + ":" + dbPort + "/" + dbName;
try {
Connection con = DriverManager.getConnection(url, dbUsername, dbPassword);
model = new DefaultTableModel();
model.addColumn("Id");
model.addColumn("Onoma");
model.addColumn("Epwnimo");
model.addColumn("Age");
model.addColumn("Nickname");
table = new JTable(model);
stmt = con.createStatement();
updateStatement( all );
} catch (SQLException ex) {
ex.printStackTrace(System.out);
}
}
public void addStatement(String name,String surname,Integer age,String nickname )
{
String query = "INSERT INTO Players (name,surname,age,nickname) VALUES ('"
+ name +
"','"
+ surname +
"',"
+ age +
",'"
+ nickname +
"')";
try {
int x = stmt.executeUpdate( query );
if (x > 0) {
lastStatement(all);
// updateStatement(all , true );
}
} catch (SQLException e) {
e.printStackTrace();
}
}
public Boolean deleteStatement(String id , int row )
{
String query = "DELETE FROM Players WHERE id = " + id ;
try {
int x = stmt.executeUpdate( query );
if (x > 0) {
model.removeRow(row);
return true;
}
return false;
} catch (SQLException e) {
e.printStackTrace();
return false;
}
}
public void updateStatement(String query , Boolean flag )
{
try {
ResultSet rs = stmt.executeQuery( query );
while (rs.next()) {
int currentId = rs.getInt("id");
String currentName = rs.getString("name");
String currentSurname = rs.getString("surname");
int currentAge = rs.getInt("age");
String currentNick = rs.getString("nickname");
Object[] currentRow = { currentId ,currentName, currentSurname, currentAge, currentNick };
model.addRow(currentRow);
}
} catch (SQLException ex) {
ex.printStackTrace(System.out);
}
}
public void updateStatement(String query) {
updateStatement(query , false );
}
public void lastStatement(String query )
{
try {
ResultSet rs = stmt.executeQuery( query );
rs.last();
int currentId = rs.getInt("id");
String currentName = rs.getString("name");
String currentSurname = rs.getString("surname");
int currentAge = rs.getInt("age");
String currentNick = rs.getString("nickname");
Object[] currentRow = { currentId ,currentName, currentSurname, currentAge, currentNick };
model.addRow(currentRow);
} catch (SQLException ex) {
ex.printStackTrace(System.out);
}
}
public JTable getTable( ) {
return table;
}
}
主类
package jtable;
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class MainD extends JFrame{
private JPanel p;
//private JPanel pa;
private JScrollPane pa; //<-- change
private JSplitPane splitPane;
private JButton b,ba;
private JLabel ln,ls,la,lc;
private JTextField txs,txn,txa,txc;
private ControlDatabase data;
private JTable table;
public MainD()
{
super("Split");
p = new JPanel(new GridLayout(5,2));
//pa = new JPanel(new GridLayout(1,1));
pa = new JScrollPane( ); //<--
ln = new JLabel("Name");
txn = new JTextField();
ls = new JLabel("Surname");
txs = new JTextField();
la = new JLabel("Age");
txa = new JTextField();
ba = new JButton("Add");
lc = new JLabel("Nickname");
txc = new JTextField();
ba.addActionListener(new ActionListener() { //Add
public void actionPerformed(ActionEvent e){
String name = txn.getText();
String surname = txs.getText();
String sage = txa.getText();
String nickname = txc.getText();
if (!( name.isEmpty() || surname.isEmpty() || nickname.isEmpty() || sage.isEmpty() )) {
try {
Integer age = Integer.parseInt( sage );
data.addStatement(name,surname,age,nickname);
txn.setText("");
txs.setText("");
txa.setText("");
txc.setText("");
}catch(NumberFormatException ex){
System.out.println("Age must be an Integer");
}
}
else{
System.out.println("Empty Fields");
}
}
}
);
b = new JButton("Remove");
data = new ControlDatabase();
table = data.getTable();
pa.add(table);
b.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e){
int row = table.getSelectedRow();
String value = String.valueOf( table.getValueAt( row ,0 ) );
data.deleteStatement( value , row );
}
}
);
p.add(ln);
p.add(txn);
p.add(ls);
p.add(txs);
p.add(la);
p.add(txa);
p.add(lc);
p.add(txc);
p.add(ba);
p.add(b);
splitPane = new JSplitPane(JSplitPane.HORIZONTAL_SPLIT, p, pa);
splitPane.setDividerLocation(280);
add(splitPane);
setBounds(200,200,800,400);
setDefaultCloseOperation(EXIT_ON_CLOSE);
setVisible(true);
}
public static void main(String[] args) {
new MainD();
}
}
推荐答案
您可能没有将表格放在 JScrollPane 中，这就是它不绘制标题的原因.或者调用 getTableHeader() 并单独添加.引用自 JTable javadoc:
You probably didn't put the table in a JScrollPane, which is why it does not draw the header. Or call getTableHeader() and add it separately. Quoting from JTable javadoc:
请注意，如果您希望在独立视图中使用 JTable(在一个 JScrollPane) 并希望显示标题，您可以使用getTableHeader() 并单独显示.
要将组件添加到 JScrollPane 要么将组件提供给 JScrollPane 的构造函数，要么调用 JScrollPane.setViewportView(component)
To add a component to a JScrollPane either give the component to the constructor of the JScrollPane, or call JScrollPane.setViewportView(component)
这篇关于没有列名的 DefaultTableModel的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！