Question

哪位高手帮忙改一下这个JAVA程序,现在在eclipse运行不成功,谢谢！

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.JFrame;
import javax.swing.JPanel;
import java.awt.Dimension;
import javax.swing.JTextField;
import javax.swing.JButton;
import javax.swing.JLabel;
import java.awt.Rectangle;
import javax.swing.JTextArea;
class Num extends JFrame implements ActionListener {

private JFrame jFrame = null;
private JPanel jContentPane = null;
private JLabel jLabel = null;
private JTextField jTextField = null;
private JButton jButton = null;
private JTextArea jTextArea = null;
private JFrame getJFrame() {
if (jFrame == null) {
jFrame = new JFrame();
jFrame.setSize(new Dimension(450, 210));
jFrame.setTitle("提取数字");
jFrame.setContentPane(getJContentPane());
}
return jFrame;
}
private JPanel getJContentPane() {
if (jContentPane == null) {
jLabel = new JLabel();
jLabel.setBounds(new Rectangle(10, 5, 65, 30));
jLabel.setText("输入字符串");
jContentPane = new JPanel();
jContentPane.setLayout(null);
jContentPane.add(jLabel, null);
jContentPane.add(getJTextField(), null);
jContentPane.add(getJButton(), null);
jContentPane.add(getJTextArea(), null);
}
return jContentPane;
}
private JTextField getJTextField() {
if (jTextField == null) {
jTextField = new JTextField();
jTextField.setBounds(new Rectangle(90, 4, 220, 35));
}
return jTextField;
}
private JButton getJButton() {
if (jButton == null) {
jButton = new JButton();
jButton.setBounds(new Rectangle(325, 4, 80, 35));
jButton.setText("确定");
jButton.addActionListener(this) ;

}
return jButton;
}
private JTextArea getJTextArea() {
if (jTextArea == null) {
jTextArea = new JTextArea();
jTextArea.setBounds(new Rectangle(2, 45,430, 125));
jTextArea.setText("");
}
return jTextArea;
}

public void actionPerformed(ActionEvent e)
{

String str;
str=jTextField.getText();
char s[]={};
int a[]={0};
int i,k,m;
i=0;k=0;m=0;

char p[]=str.toCharArray();
while(p[m]!='\0')
{
if(p[m]>='0'&&p[m]<='9')
{
s[i]=p[m];
a[k]=10*a[k]+s[i]-'0';
i++;

}
else
{
if(i>0)
{
k++;
i=0;
}

}
m++;

}
if(i>0)
k++;
jTextArea.append("字符串中有"+k+"个数字，分别为：\n");
for(i=0;i<k;i++)
jTextArea.append(a[i]+"n");
}
}
public class Java
{
public static void main(String args[])
{
JFrame Num=new JFrame();
}
}

Answer 1

一下代码是我在你写的代码基础上修改的：
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.JFrame;
import javax.swing.JPanel;
import java.awt.Dimension;
import javax.swing.JTextField;
import javax.swing.JButton;
import javax.swing.JLabel;
import java.awt.Rectangle;
import javax.swing.JTextArea;
class Num extends JFrame implements ActionListener {

private JFrame jFrame = null; //删掉
private JPanel jContentPane = null;
private JLabel jLabel = null;
private JTextField jTextField = null;
private JButton jButton = null;
private JTextArea jTextArea = null;
private JFrame getJFrame() { //修改成： public Num(){
if (jFrame == null) { //删掉
jFrame = new JFrame(); //删掉
jFrame.setSize(new Dimension(450, 210)); //修改成： this.setSize(new Dimension(450, 210));
jFrame.setTitle("提取数字"); //修改成： this.setTitle("提取数字");
jFrame.setContentPane(getJContentPane()); //修改成： this.setContentPane(getJContentPane());
} //删掉
return jFrame; //删掉
//增加： this.setVisible(true);
}
private JPanel getJContentPane() {
if (jContentPane == null) {
jLabel = new JLabel();
jLabel.setBounds(new Rectangle(10, 5, 65, 30));
jLabel.setText("输入字符串");
jContentPane = new JPanel();
jContentPane.setLayout(null);
jContentPane.add(jLabel, null);
jContentPane.add(getJTextField(), null);
jContentPane.add(getJButton(), null);
jContentPane.add(getJTextArea(), null);
}
return jContentPane;
}
private JTextField getJTextField() {
if (jTextField == null) {
jTextField = new JTextField();
jTextField.setBounds(new Rectangle(90, 4, 220, 35));
}
return jTextField;
}
private JButton getJButton() {
if (jButton == null) {
jButton = new JButton();
jButton.setBounds(new Rectangle(325, 4, 80, 35));
jButton.setText("确定");
jButton.addActionListener(this) ;

}
return jButton;
}
private JTextArea getJTextArea() {
if (jTextArea == null) {
jTextArea = new JTextArea();
jTextArea.setBounds(new Rectangle(2, 45,430, 125));
jTextArea.setText("");
}
return jTextArea;
}

public void actionPerformed(ActionEvent e)
{

String str;
str=jTextField.getText();
char s[]={};
/* //删掉整个注释里的内容：
int a[]={0};
int i,k,m;
i=0;k=0;m=0;

char p[]=str.toCharArray();
while(p[m]!='\0')
{
if(p[m]>='0'&&p[m]<='9')
{
s[i]=p[m];
a[k]=10*a[k]+s[i]-'0';
i++;

}
else
{
if(i>0)
{
k++;
i=0;
}

}
m++;

}
if(i>0)
k++;
jTextArea.append("字符串中有"+k+"个数字，分别为：\n");
for(i=0;i<k;i++)
jTextArea.append(a[i]+"n");
}
*/

//增加下面的内容：
int k;
k=0;

char p[]=str.toCharArray();
s = p;
for(int j = 0; j < p.length; j++)
{
if(p[j] >= '0' && p[j] <= '9')
{
s[k] = p[j];
k++;
}
}
if(k == 0)
{
jTextArea.setText("字符串中有"+k+"个数字\n");
}
else
{
jTextArea.setText("字符串中有"+k+"个数字，分别为：\n");
for(int z = 0; z < k; z++)
{
jTextArea.append(s[z]+"\n");
}
}
}
public class Java
{
public static void main(String args[])
{
JFrame Num=new JFrame();//删掉
//增加： Num JFrame = new Num();
}
}

而下面的代码是我修改后可直接运行的代码：
他们有不同之处，请自己看看：

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.JFrame;
import javax.swing.JPanel;
import java.awt.Dimension;
import javax.swing.JTextField;
import javax.swing.JButton;
import javax.swing.JLabel;
import java.awt.Rectangle;
import javax.swing.JTextArea;
class Num extends JFrame implements ActionListener {

private JPanel jContentPane = null;
private JLabel jLabel = null;
private JTextField jTextField = null;
private JButton jButton = null;
private JTextArea jTextArea = null;
public Num() {
this.setSize(new Dimension(450, 210));
this.setTitle("提取数字");
this.setContentPane(getJContentPane());
this.setVisible(true);
}
private JPanel getJContentPane() {
if (jContentPane == null) {
jLabel = new JLabel();
jLabel.setBounds(new Rectangle(10, 5, 65, 30));
jLabel.setText("输入字符串");
jContentPane = new JPanel();
jContentPane.setLayout(null);
jContentPane.add(jLabel, null);
jContentPane.add(getJTextField(), null);
jContentPane.add(getJButton(), null);
jContentPane.add(getJTextArea(), null);
}
return jContentPane;
}
private JTextField getJTextField() {
if (jTextField == null) {
jTextField = new JTextField();
jTextField.setBounds(new Rectangle(90, 4, 220, 35));
}
return jTextField;
}
private JButton getJButton() {
if (jButton == null) {
jButton = new JButton();
jButton.setBounds(new Rectangle(325, 4, 80, 35));
jButton.setText("确定");
jButton.addActionListener(this) ;

}
return jButton;
}
private JTextArea getJTextArea() {
if (jTextArea == null) {
jTextArea = new JTextArea();
jTextArea.setBounds(new Rectangle(2, 45,430, 125));
jTextArea.setText("");
}
return jTextArea;
}

public void actionPerformed(ActionEvent e)
{

String str;
str=jTextField.getText();

char s[]={};
int k;
k=0;

char p[]=str.toCharArray();
s = p;
for(int j = 0; j < p.length; j++)
{
if(p[j] >= '0' && p[j] <= '9')
{
s[k] = p[j];
k++;
}
}
if(k == 0)
{
jTextArea.setText("字符串中有"+k+"个数字\n");
}
else
{
jTextArea.setText("字符串中有"+k+"个数字，分别为：\n");
for(int z = 0; z < k; z++)
{
jTextArea.append(s[z]+"\n");
}
}
}
}
public class Java
{
public static void main(String args[])
{
Num JFrame = new Num();
}
}
首先你在main函数当中应该创建你自己的写的类Num，不然怎么
会运行Num类当中的方法，而你在main函数中创建JFrame类是可以编译的，但是根本无法调用Num类中的方法getJFrame（），而这个getJFrame()，你的意图是将它设为构造函数，但是这样的写法不对，构造函数应该是public修饰，函数名即为类名Num。
这里的Num因为继承了JFrame类，可以认为他就可以行使JFrame类
权利，当所有容器都放入JFrame类后要将它显示出来，因为，
默认的它是不显示的，即写出this.setVisible(true);

Answer 2

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.JFrame;
import javax.swing.JPanel;
import java.awt.Dimension;
import javax.swing.JTextField;
import javax.swing.JButton;
import javax.swing.JLabel;
import java.awt.Rectangle;
import javax.swing.JTextArea;
class Num extends JFrame implements ActionListener {

private JPanel jContentPane = null;
private JLabel jLabel = null;
private JTextField jTextField = null;
private JButton jButton = null;
private JTextArea jTextArea = null;
//原来的getJFrame函数改成现在的Num构造函数
public Num() {
super("提取数字");
setSize(new Dimension(450, 210));
setContentPane(getJContentPane());
setVisible(true);
}
private JPanel getJContentPane() {
if (jContentPane == null) {
jLabel = new JLabel();
jLabel.setBounds(new Rectangle(10, 5, 65, 30));
jLabel.setText("输入字符串");
jContentPane = new JPanel();
jContentPane.setLayout(null);
jContentPane.add(jLabel, null);
jContentPane.add(getJTextField(), null);
jContentPane.add(getJButton(), null);
jContentPane.add(getJTextArea(), null);
}
return jContentPane;
}
private JTextField getJTextField() {
if (jTextField == null) {
jTextField = new JTextField();
jTextField.setBounds(new Rectangle(90, 4, 220, 35));
}
return jTextField;
}
private JButton getJButton() {
if (jButton == null) {
jButton = new JButton();
jButton.setBounds(new Rectangle(325, 4, 80, 35));
jButton.setText("确定");
jButton.addActionListener(this) ;
}
return jButton;
}
private JTextArea getJTextArea() {
if (jTextArea == null) {
jTextArea = new JTextArea();
jTextArea.setBounds(new Rectangle(2, 45,430, 125));
jTextArea.setText("");
}
return jTextArea;
}

public void actionPerformed(ActionEvent e)
{
//算法太差，下标一个劲越界，懒的给你看了，重给你写一个
int count=0,i;
String strNumber="";
char[] chars=jTextField.getText().toCharArray();
for(char ch:chars){
if(ch>='0'&&ch<='9'){
strNumber+=ch;
count++;
}
}
jTextArea.append(String.format("字符串中有%1$d个数字，分别为：\n%2$s\n",count,strNumber));
}
}
public class Java
{
public static void main(String args[])
{
//原来创建JFrame实例现在改成创建Num实例
Num num=new Num();
}
}

Answer 3

JFrame Num=new JFrame();后面加一句
Num.setVisible(true);试一下