我创建了一个 JFrame，里面有一个 JTable，我可以在单元格上写入信息。我可以单击 Save JMenuItem Save 并将信息写入 txt 文件。 但是，当我尝试读取该文件并将其带回到表中时，我面临三个问题。
- JTable 由 30 行组成。当代码读取 txt 文件时，在第 30 行下方添加行。有没有办法从第一行而不是第 31 行开始填充输入？ -- 已解决
- 数据写入不正确。所有这些都写在第一栏——已解决
- 如何去掉“null”字符串？ --已解决
我的txt文件格式是这样的:
Number;Type;IP;Protocol;Line;
49897223040;WE4;192.168.12.98;TCP;Single;
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;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;
我的代码如下:
public class PhoneOrganiser extends JFrame {
public static void main(String[] args){
//creation of the Window
JFrame frame = new JFrame ("Phone Organiser");
frame.setSize(200, 300);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
//declaring the type of Table, Number of columns and rows
String col[] ={"Number", "Type", "IP", "Protocol", "Line"};
DefaultTableModel tableModel = new DefaultTableModel (col,30);
//create the table
JTable table = new JTable(tableModel);
//add the Table to the scrollpane
JScrollPane scrollpane = new JScrollPane(table);
frame.add(scrollpane);
//creating the Menu bar
JMenuBar menubar = new JMenuBar();
frame.setJMenuBar(menubar);
//adding menus
JMenu file = new JMenu ("File");
menubar.add(file);
JMenu help = new JMenu ("Help");
menubar.add(help);
//adding items inside the menus
JMenuItem open = new JMenuItem ("Open");
file.add(open);
JMenuItem save = new JMenuItem ("Save");
file.add(save);
JMenuItem exit = new JMenuItem ("Exit");
file.add(exit);
exit.addActionListener(new Exit());
JMenuItem readMe = new JMenuItem ("Read me file");
help.add(readMe);
readMe.addActionListener(new ReadMe());
JMenuItem about = new JMenuItem ("About");
help.add(about);
about.addActionListener(new About());
//When the program starts for the first time, it creates a new txt file
Path path = Paths.get("/Users/PhoneData.txt");
try{
Files.createFile(path);
System.out.println("file created");
}catch (IOException e1){
System.out.println("file already exists");
}
//saving data from TABLE -> TO TXT - It can be done with FileChooser in V2
class SaveData extends JFrame implements ActionListener {
public void actionPerformed (ActionEvent e){
try{
File file = new File ("C:\\Users\\PhoneData.txt"); //declaring the path of the file
FileWriter fw = new FileWriter (file.getAbsoluteFile());
BufferedWriter bw = new BufferedWriter (fw);
//rows
for (int i =0; i < table.getRowCount(); i++){
//columns
for (int j=0; j < table.getColumnCount(); j++){
bw.write((String)table.getModel().getValueAt(i, j)+ ";"); //write the contents to the file
}
bw.write("/");
bw.newLine();
}
bw.close();
fw.close();
}catch (IOException e2){
}//end catch
}//end action method
}save.addActionListener(new SaveData()); //end SaveData class
//reading data from TXT -> TO TABLE
class OpenData extends JFrame implements ActionListener{
public void actionPerformed (ActionEvent e){
String line = null;
try{
File file = new File ("C:\\Users\\PhoneData.txt");
FileReader fr = new FileReader (file.getAbsoluteFile());
BufferedReader br = new BufferedReader (fr);
while((line = br.readLine()) != "null;")
{
String [] splitData = line.split("/");
Values values = new Values();
values.setNumber(splitData[0]);
//values.setType(splitData[1]);
//values.setIP(splitData[2]);
//values.setProtocol(splitData[3]);
//values.setLine(splitData[4]);
tableModel.addRow(line.split(""));
}
br.close();
}catch (IOException e3){
}//end catch
}//end action method
}open.addActionListener(new OpenData());//end OpenData class
}//end main
}//end class
public class Values{
private String Number;
private String Type;
private String IP;
private String Protocol;
private String Line;
public String getNumber(){
return Number;
}
public void setNumber(String Number){
this.Number = Number;
}
public String getType(){
return Type;
}
public void setType(String Type){
this.Type = Type;
}
public String getIP(){
return IP;
}
public void setIP(String IP){
this.IP = IP;
}
public String getProtocol(){
return Protocol;
}
public void setProtocol(String Protocol){
this.Protocol = Protocol;
}
public String getLine(){
return Line;
}
public void setLine(String Line){
this.Line = Line;
}
}//end class Values
最佳答案
广告.3 代码非常清晰:
for (int j=0; j < table.getColumnCount(); j++){
String value = (String)table.getModel().getValueAt(i, j);
if((value == null || "null".equals(value)){
value = "";
}
bw.write(value+";"); //write the contents to the file
}
广告.2 需要对代码进行简单修改:
StringBuilder builder = new StringBuilder();
while ((line = bufferedReader.readLine()) != null) {
builder.append(line);
}
String[] lineArray= builder.toString().split("/");
for(String line: lineArray){
String[] dataArray = line.split(";");
tableModel.addRow(dataArray);
}
广告.1 希望这是您想要实现的目标。完整代码如下:
public class PhoneOrganiser extends JFrame {
public static void main(String[] args){
//creation of the Window
JFrame frame = new JFrame ("Phone Organiser");
frame.setSize(200, 300);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
//declaring the type of Table, Number of columns and rows
final String col[] ={"Number", "Type", "IP", "Protocol", "Line"};
final DefaultTableModel tableModel = new DefaultTableModel (col,30);
//create the table
final JTable table = new JTable(tableModel);
//add the Table to the scrollpane
JScrollPane scrollpane = new JScrollPane(table);
frame.add(scrollpane);
//creating the Menu bar
JMenuBar menubar = new JMenuBar();
frame.setJMenuBar(menubar);
//adding menus
JMenu file = new JMenu ("File");
menubar.add(file);
JMenu help = new JMenu ("Help");
menubar.add(help);
//adding items inside the menus
JMenuItem open = new JMenuItem ("Open");
file.add(open);
JMenuItem save = new JMenuItem ("Save");
file.add(save);
JMenuItem exit = new JMenuItem ("Exit");
file.add(exit);
//When the program starts for the first time, it creates a new txt file
Path path = Paths.get("/Users/PhoneData.txt");
try{
Files.createFile(path);
System.out.println("file created");
}catch (IOException e1){
System.out.println("file already exists");
}
//saving data from TABLE -> TO TXT - It can be done with FileChooser in V2
class SaveData extends JFrame implements ActionListener {
public void actionPerformed (ActionEvent e){
try{
File file = new File ("C:\\Inne\\PhoneData.txt"); //declaring the path of the file
FileWriter fw = new FileWriter (file.getAbsoluteFile());
BufferedWriter bw = new BufferedWriter (fw);
//rows
for (int i =0; i < table.getRowCount(); i++){
for (int j=0; j < table.getColumnCount(); j++){
String value = (String)table.getModel().getValueAt(i, j);
if((value == null || "null".equals(value))) {
value = "";
}
bw.write(value+";"); //write the contents to the file
}
bw.write("/");
bw.newLine();
}
bw.close();
fw.close();
}catch (IOException e2){
}//end catch
}//end action method
}
save.addActionListener(new SaveData()); //end SaveData class
//reading data from TXT -> TO TABLE
class OpenData extends JFrame implements ActionListener{
public void actionPerformed (ActionEvent e){
String line = null;
try{
File file = new File ("C:\\Inne\\PhoneData.txt");
FileReader fr = new FileReader (file.getAbsoluteFile());
BufferedReader br = new BufferedReader (fr);
StringBuilder builder = new StringBuilder();
while ((line = br.readLine()) != null) {
builder.append(line);
}
String[] lineArray= builder.toString().split("/");
table.setModel(new DefaultTableModel(col,0));
for(String currentLine: lineArray){
String[] dataArray = currentLine.split(";");
((DefaultTableModel)table.getModel()).addRow(dataArray);
}
br.close();
}catch (IOException e3){
}//end catch
}//end action method
}open.addActionListener(new OpenData());//end OpenData class
}
}
关于java - 我想从 txt 文件读取数据并写入现有的 JTable，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/31318587/