我是 Java 的新手，在编译时总是遇到错误，特别是“找不到符号错误”。我试图让表中的字符串作为文件目标进入，但我无法调用该表，所以我尝试使用变量 holder，结果再次出错。
与此同时，我试图更改可以在文件选择器上打开的文件类型，但我找不到可行的解决方案。
最后，有人可以解释什么是缺失符号吗？因为我觉得我误解了它，因为我已经尝试修复它很多次但都没有成功。
//C:\\Users\\Andrew\\Downloads\\never gonna give you up.wav
//Andrew Douglas
//Imports
import javax.swing.*;
import javax.swing.event.*;
import java.awt.*;
import java.awt.event.*;
import java.io.*;
import javax.sound.sampled.*;
import javax.swing.filechooser.*;
import javax.swing.JTable;
//Creates class
public class jPlayer extends JFrame implements ActionListener {
//Sets up form items and necessary globals
JButton save, play, stop, loop;
JFileChooser dialog;
String Artist, Song, Album, Loc;
Object[][] data;
int n = 1;
String holder;
//Makes the library, with a 51 song limit.
jLibrary[] addedSong = new jLibrary[50];
public jPlayer() {
//Creates frame
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
this.setTitle("jPlayer");
this.setSize(800, 600);
//Makes titles for table
String[] columnNames = {"Artist",
"Song",
"Album",
"Location"};
//Gives one value for array
addedSong[0] = new jLibrary("Rick Astley", "NGGYU", "UnKnown", "C:\\Users\\Andrew\\Downloads\\never gonna give you up.wav");
//Adds it to table array
Object[][] data = {
{
addedSong[0]
}
};
//Creates table
final Jtable table = new JTable(data, columnNames);
table.setPreferredScrollableViewportSize(new Dimension(500, 70));
table.setFillsViewportHeight(true);
//Lets it sort the rows
table.setAutoCreateRowSorter(true);
//Creates the scroller
JScrollPane scrollPane = new JScrollPane(table);
//Makes the save file dialog and the play and save buttons
dialog = new JFileChooser();
play = new JButton ("Play Song");
save = new JButton ("Save a file");
//Adds the button listeners
save.addActionListener(this);
play.addActionListener(this);
//Adds buttons to panel
JPanel buttons = new JPanel();
buttons.add(save);
buttons.add(play);
//Puts the buttons at the bottom
add(buttons, BorderLayout.SOUTH);
add(scrollPane);
this.setVisible(true);
holder = table.getselectedRows[3];
}
//Creates action listener for button
public void actionPerformed(ActionEvent e) {
if (e.getSource() == save) {
dialog.setFileFilter(new FileNameExtensionFiler("Wave File (*.wav)"));
int returnVal = dialog.showSaveDialog(jPlayer.this);
if (returnVal == dialog.APPROVE_OPTION) {
File file = dialog.getSelectedFile();
addToLibrary("", "", "", file.getName());
}
}
else if (e.getSource() == play) {
try {
File soundFile = new File(holder);
System.out.println(soundFile);
AudioInputStream audioIn = AudioSystem.getAudioInputStream(soundFile);
Clip clip = AudioSystem.getClip();
clip.open(audioIn);
clip.start();
} catch (UnsupportedAudioFileException f) {
f.printStackTrace();
} catch (IOException f) {
f.printStackTrace();
} catch (LineUnavailableException f) {
f.printStackTrace();
}
} }
public static void main(String[]args) {
new jPlayer();
}
public void addToLibrary(String art, String song, String alb, String file) {
addedSong[n] = new jLibrary(art, song, alb, file);
int j = 0;
while (n >= 0) {
Object[][] data = {
{
addedSong[(n-j)],
}
};
j = j+1;
}
n = n +1;
}
}
错误:
--------------------Configuration: <Default>--------------------
C:\Users\Andrew\Documents\ICS4U Final\jPlayer.java:47: error: cannot find symbol
final Jtable table = new JTable(data, columnNames);
^
symbol: class Jtable
location: class jPlayer
C:\Users\Andrew\Documents\ICS4U Final\jPlayer.java:75: error: cannot find symbol
dialog.setFileFilter(new FileNameExtensionFiler("Wave File (*.wav)"));
^
symbol: class FileNameExtensionFiler
location: class jPlayer
2 errors
Process completed.
抱歉所有问题，感谢您的帮助!
编辑:我已将 Jtable 更改为 JTable，并将 t 添加到过滤器中，并删除了 holder，因为我不再需要它了。
代码现在看起来像:
//C:\\Users\\Andrew\\Downloads\\never gonna give you up.wav
//Andrew Douglas
//Imports
import javax.swing.*;
import javax.swing.event.*;
import java.awt.*;
import java.awt.event.*;
import java.io.*;
import javax.sound.sampled.*;
import javax.swing.filechooser.*;
import javax.swing.JTable;
//Creates class
public class JPlayer extends JFrame implements ActionListener {
//Sets up form items and necessary globals
JButton save, play, stop, loop;
JFileChooser dialog;
String Artist, Song, Album, Loc;
Object[][] data;
int n = 1;
//Makes the library, with a 51 song limit.
jLibrary[] addedSong = new jLibrary[50];
public JPlayer() {
//Creates frame
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
this.setTitle("jPlayer");
this.setSize(800, 600);
//Makes titles for table
String[] columnNames = {"Artist",
"Song",
"Album",
"Location"};
//Gives one value for array
addedSong[0] = new jLibrary("Rick Astley", "NGGYU", "UnKnown", "C:\\Users\\Andrew\\Downloads\\never gonna give you up.wav");
//Adds it to table array
Object[][] data = {
{
addedSong[0]
}
};
//Creates table
final JTable table = new JTable(data, columnNames);
table.setPreferredScrollableViewportSize(new Dimension(500, 70));
table.setFillsViewportHeight(true);
//Lets it sort the rows
table.setAutoCreateRowSorter(true);
//Creates the scroller
JScrollPane scrollPane = new JScrollPane(table);
//Makes the save file dialog and the play and save buttons
dialog = new JFileChooser();
play = new JButton ("Play Song");
save = new JButton ("Save a file");
//Adds the button listeners
save.addActionListener(this);
play.addActionListener(this);
//Adds buttons to panel
JPanel buttons = new JPanel();
buttons.add(save);
buttons.add(play);
//Puts the buttons at the bottom
add(buttons, BorderLayout.SOUTH);
add(scrollPane);
this.setVisible(true);
}
//Creates action listener for button
public void actionPerformed(ActionEvent e) {
if (e.getSource() == save) {
dialog.setFileFilter(new FileNameExtensionFilter("Wave File (*.wav)"));
int returnVal = dialog.showSaveDialog(JPlayer.this);
if (returnVal == dialog.APPROVE_OPTION) {
File file = dialog.getSelectedFile();
addToLibrary("", "", "", file.getName());
}
}
else if (e.getSource() == play) {
try {
File soundFile = new File(table.getSelectedRows[3]);
System.out.println(soundFile);
AudioInputStream audioIn = AudioSystem.getAudioInputStream(soundFile);
Clip clip = AudioSystem.getClip();
clip.open(audioIn);
clip.start();
} catch (UnsupportedAudioFileException f) {
f.printStackTrace();
} catch (IOException f) {
f.printStackTrace();
} catch (LineUnavailableException f) {
f.printStackTrace();
}
} }
public static void main(String[]args) {
new jPlayer();
}
public void addToLibrary(String art, String song, String alb, String file) {
addedSong[n] = new jLibrary(art, song, alb, file);
int j = 0;
while (n >= 0) {
Object[][] data = {
{
addedSong[(n-j)],
}
};
j = j+1;
}
n = n +1;
}
}
但现在我收到了这个错误:
--------------------Configuration: <Default>--------------------
C:\Users\Andrew\Documents\ICS4U Final\JPlayer.java:83: error: cannot find symbol
File soundFile = new File(table.getSelectedRows[3]);
^
symbol: variable table
location: class JPlayer
1 error
Process completed.
有什么帮助吗？
最佳答案
你需要的类是JTable，不是Jtable
该错误基本上意味着您正在使用不存在的符号。您尝试使用的类存在于 package javax.swing(您已导入)中:javax.swing.JTable，带有一个大的 T
IDE 会帮助您找到它，但对于初学者来说，从文本编辑器开始并一个一个地查看错误也是一件好事 ;)
关于java - Java新手，找不到符号报错，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/17168670/