使用sort方法對陣列進行排序（split（）出現錯誤的解決）
原本的程式碼：
import java.awt.BorderLayout;
import java.awt.EventQueue;
import java.util.Arrays;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.border.EmptyBorder;
import javax.swing.JLabel;
import javax.swing.JTextField;
import javax.swing.JButton;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.UIManager;
import javax.swing.event.CaretListener;
import javax.swing.event.CaretEvent;
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;
public class SortArray extends JFrame {
private JPanel contentPane;
private JTextField arrayField;
private JTextArea sortArea;
/**
* Launch the application.
*/
public static void main(String[] args) {
try {
UIManager
.setLookAndFeel("com.sun.java.swing.plaf.nimbus.NimbusLookAndFeel");
} catch (Throwable e) {
e.printStackTrace();
}
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
SortArray frame = new SortArray();
frame.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
/**
* Create the frame.
*/
public SortArray() {
setTitle("\u4F7F\u7528Sort\u65B9\u6CD5\u5BF9\u6570\u7EC4\u8FDB\u884C\u6392\u5E8F");
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setBounds(100, 100, 450, 300);
contentPane = new JPanel();
contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
setContentPane(contentPane);
contentPane.setLayout(null);
JLabel label = new JLabel(
"\u8F93\u5165\u6570\u7EC4\u5185\u5BB9\uFF0C\u7A7A\u683C\u4E3A\u6570\u7EC4\u5143\u7D20\u5206\u9694\u7B26");
label.setBounds(6, 6, 265, 18);
contentPane.add(label);
arrayField = new JTextField();
arrayField.addKeyListener(new KeyAdapter() {
@Override
public void keyPressed(KeyEvent e) {
}
@Override
public void keyTyped(KeyEvent e) {
char key = e.getKeyChar();
String mask = "0123456789 " + (char) 8;
if (mask.indexOf(key) == -1) {
e.consume();
}
}
});
arrayField.setBounds(6, 36, 422, 30);
contentPane.add(arrayField);
arrayField.setColumns(10);
JButton button = new JButton("\u6392\u5E8F");
button.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
do_button_actionPerformed(e);
}
});
button.setBounds(164, 78, 90, 30);
contentPane.add(button);
JScrollPane scrollPane = new JScrollPane();
scrollPane.setBounds(6, 118, 422, 138);
contentPane.add(scrollPane);
sortArea = new JTextArea();
sortArea.setLineWrap(true);
scrollPane.setViewportView(sortArea);
}
protected void do_button_actionPerformed(ActionEvent e) {
String text = arrayField.getText();// 獲取使用者輸入
String[] arrayStr = text.split(" {1,}");// 拆分輸入為陣列
int[] array = new int[arrayStr.length];// 建立整數型別陣列
sortArea.setText("陣列原有內容：\n");
for (String string : arrayStr) {// 輸出原有陣列內容
sortArea.append(string + " ");
}
for (int i = 0; i < array.length; i++) {// 初始化整形陣列
array[i] = Integer.parseInt(arrayStr[i]);
}
sortArea.append("\n");
Arrays.sort(array);// 使用sort方法對整形陣列進行排序
sortArea.append("陣列排序後的內容：\n");
for (int value : array) {// 輸出排序後的陣列內容
sortArea.append(value + " ");
}
}
protected void do_arrayField_keyPressed(KeyEvent e) {
char key = e.getKeyChar();// 獲取使用者按鍵字元
String mask = "0123456789 " + (char) 8;// 定義規範化字元模板
if (mask.indexOf(key) == -1) {// 判斷按鍵字元是否屬於規範化字元範圍
e.consume();// 取消非規範化字元的輸入有效性
}
}
}
學習的程式碼：
import java.awt.BorderLayout;
import java.awt.EventQueue;
import java.util.Arrays;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.border.EmptyBorder;
import javax.swing.JLabel;
import javax.swing.JTextField;
import javax.swing.JButton;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.UIManager;
import javax.swing.event.CaretListener;
import javax.swing.event.CaretEvent;
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;
public class SortArray extends JFrame {
private JPanel contentPane;
private JTextField arrayField;
private JTextArea sortArea;
/**
* Launch the application.
*/
public static void main(String[] args) {
try {
UIManager
.setLookAndFeel("com.sun.java.swing.plaf.nimbus.NimbusLookAndFeel");
} catch (Throwable e) {
e.printStackTrace();
}
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
SortArray frame = new SortArray();
frame.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
/**
* Create the frame.
*/
public SortArray() {
setTitle("\u4F7F\u7528Sort\u65B9\u6CD5\u5BF9\u6570\u7EC4\u8FDB\u884C\u6392\u5E8F");
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setBounds(100, 100, 450, 300);
contentPane = new JPanel();
contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
setContentPane(contentPane);
contentPane.setLayout(null);
JLabel label = new JLabel(
"\u8F93\u5165\u6570\u7EC4\u5185\u5BB9\uFF0C\u7A7A\u683C\u4E3A\u6570\u7EC4\u5143\u7D20\u5206\u9694\u7B26");
label.setBounds(6, 6, 265, 18);
contentPane.add(label);
arrayField = new JTextField();
arrayField.addKeyListener(new KeyAdapter() {
@Override
public void keyPressed(KeyEvent e) {
}
@Override
public void keyTyped(KeyEvent e) {
char key = e.getKeyChar();
String mask = "0123456789 " + (char) 8;
if (mask.indexOf(key) == -1) {
e.consume();
}
}
});
arrayField.setBounds(6, 36, 422, 30);
contentPane.add(arrayField);
arrayField.setColumns(10);
JButton button = new JButton("\u6392\u5E8F");
button.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
do_button_actionPerformed(e);
}
});
button.setBounds(164, 78, 90, 30);
contentPane.add(button);
JScrollPane scrollPane = new JScrollPane();
scrollPane.setBounds(6, 118, 422, 138);
contentPane.add(scrollPane);
sortArea = new JTextArea();
sortArea.setLineWrap(true);
scrollPane.setViewportView(sortArea);
}
protected void do_button_actionPerformed(ActionEvent e) {
String text = arrayField.getText();// 獲取使用者輸入
String[] arrayStr = text.split("{1,}");// 拆分輸入為陣列
int[] array = new int[arrayStr.length];// 建立整數型別陣列
sortArea.setText("陣列原有內容：\n");
for (String string : arrayStr) {// 輸出原有陣列內容
sortArea.append(string + " ");
}
for (int i = 0; i < array.length; i++) {// 初始化整形陣列
array[i] = Integer.parseInt(arrayStr[i]);
}
sortArea.append("\n");
Arrays.sort(array);// 使用sort方法對整形陣列進行排序
sortArea.append("陣列排序後的內容：\n");
for (int value : array) {// 輸出排序後的陣列內容
sortArea.append(value + " ");
}
}
protected void do_arrayField_keyPressed(KeyEvent e) {
char key = e.getKeyChar();// 獲取使用者按鍵字元
String mask = "0123456789 " + (char) 8;// 定義規範化字元模板
if (mask.indexOf(key) == -1) {// 判斷按鍵字元是否屬於規範化字元範圍
e.consume();// 取消非規範化字元的輸入有效性
}
}
}
結果：
出現錯誤提示：
Exception in thread "AWT-EventQueue-0" java.lang.NumberFormatException: For input string: " "
at java.lang.NumberFormatException.forInputString(Unknown Source)
at java.lang.Integer.parseInt(Unknown Source)
at java.lang.Integer.parseInt(Unknown Source)
at san.SortArray.do_button_actionPerformed(SortArray.java:105)
at san.SortArray$3.actionPerformed(SortArray.java:81)
at javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
at javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.setPressed(Unknown Source)
at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(Unknown Source)
at java.awt.Component.processMouseEvent(Unknown Source)
at javax.swing.JComponent.processMouseEvent(Unknown Source)
at java.awt.Component.processEvent(Unknown Source)
。。。。。
原因：
對split（）理解不透徹。
將字串按照括號內的內容分割成字元陣列
這裡括號內是正則表示式，X{m,n}代表X至少重複m次，至多重複n次
這裡空格至少重複1次，就是將字串以一個或多個空格分割
解決：
split( "{1,}")中的括號內有一個空格，自己忘了寫了，添加了之後就可以了。