简单程序停止编译过程的Java错误，请帮助 [英] Java Errors for simple program stop compiling process, please help
问题描述
我是这里的初学者，但我已经处理这个未知问题有一段时间了.请查看我编写的这个简单程序并解释为什么它不能为我编译.问题是我从一位老师那里复制了这段代码，并且在他的机器上运行良好.然后当我试图在我的机器上运行这个例子时，我得到了 13 个错误！
I am a beginner here, but I have been dealing with this unknown issue for a while now. Please view this simple program that I have coded and explain why it will not compile for me. The thing is that I have copied this code from a teacher and it works fine on his machine. Then when I tried to run the example on my machine I get 13 errors!
这是第一堂课:
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
class radio extends JFrame{
private JTextField tf;
private Font pf;
private Font bf;
private Font itf;
private Font bif;
private JRadioButton pb;
private JRadioButton bb;
private JRadioButton ib;
private JRadioButton bib;
private ButtonGroup group;
public radio(){
super("raido buttonseses");
setLayout(new FlowLayout());
tf = new JTextField("buggedy buggedy boo", 25);
add(tf);
pb = new JRadioButton("plain", true);
bb = new JRadioButton("bold", false);
ib = new JRadioButton("italic", false);
bib = new JRadioButton("bold and italic", false);
add(pb);
add(bb);
add(ib);
add(bib);
group = new ButtonGroup();
group.add(pb);
group.add(bb);
group.add(ib);
group.add(bib);
pf = new Font("Serif", Font.PLAIN, 14);
bf = new Font("Serif", Font.BOLD, 14);
itf = new Font("Serif", Font.ITALIC, 14);
bif = new Font("Serif", Font.BOLD + Font.ITALIC, 14);
tf.setFont(pf);
//wait for event to happen pass in font obj to constructor
pb.addItemListener(new HandlerClass(pf));
bb.addItemListener(new HandlerClass(bf));
ib.addItemListener(new HandlerClass(itf));
bib.addItemListener(new HandlerClass(bif));
}
private class HandlerClass implements ItemListener{
private Font font;
// font obj gets variable font
public HandlerClass(Font f){
font = f;
}
//sets font to font obj that was passed in
public void itemStateChanged(ItemEvent event){
tf.setFont(font);
}
}
}
然后这是我一直在尝试运行的第二个主类:
Then here is the second main class that I have been trying to run:
import javax.swing.JFrame;
public class radiobutton{
public static void main(String[] args) {
radio go = new radio();
go.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
go.setSize(300,200);
go.setVisible(true);
}
}
我知道有人在看这个并认为答案是如此明显，但对于像我这样的初学者来说并不是很清楚.以下是我尝试编译时返回给我的错误:
I know someone is looking at this and thinking that the answer is so obvious, but to a beginner like me it is not very clear. Here are the errors that I have returned to me when I try to compile:
javac radiobutton.java
./JFrame.java:1: JFrame is already defined in this compilation unit
import javax.swing.JFrame;
^
radiobutton.java:7: cannot find symbol
symbol : method setDefaultCloseOperation(int)
location: class radio
go.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
^
radiobutton.java:8: cannot find symbol
symbol : method setSize(int,int)
location: class radio
go.setSize(300,200);
^
radiobutton.java:9: cannot find symbol
symbol : method setVisible(boolean)
location: class radio
go.setVisible(true);
^
./JFrame.java:8: cannot find symbol
symbol : variable EXIT_ON_CLOSE
location: class JFrame
go.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
^
./radio.java:19: cannot find symbol
symbol : constructor JFrame(java.lang.String)
location: class JFrame
super("raido buttonseses");
^
./radio.java:20: cannot find symbol
symbol : method setLayout(java.awt.FlowLayout)
location: class radio
setLayout(new FlowLayout());
^
./radio.java:22: cannot find symbol
symbol : class JTExtField
location: class radio
tf = new JTExtField("buggedy buggedy boo", 25);
^
./radio.java:23: cannot find symbol
symbol : method add(javax.swing.JTextField)
location: class radio
add(tf);
^
./radio.java:30: cannot find symbol
symbol : method add(javax.swing.JRadioButton)
location: class radio
add(pb);
^
./radio.java:31: cannot find symbol
symbol : method add(javax.swing.JRadioButton)
location: class radio
add(bb);
^
./radio.java:32: cannot find symbol
symbol : method add(javax.swing.JRadioButton)
location: class radio
add(ib);
^
./radio.java:33: cannot find symbol
symbol : method add(javax.swing.JRadioButton)
location: class radio
add(bib);
^
13 errors
我的猜测是这与java函数导入中的星号有关.我在正确的轨道上吗?感谢您查看这个愚蠢的问题，非常感谢您的帮助.
My guess is that this has something to do with the asterisk in the import of the java functions. Am I on the right track here? Thank you for having a look at this silly problem and any help is much appreciated.
推荐答案
它对我来说编译得很好.
It compiles just fine for me.
错误可能是这样的:您的源目录中有另一个名为 JFrame.java 的文件.删除此文件！JFrame 已在 API 中定义.
The error is probably this: You have another file called JFrame.java in your source directory. Remove this file! JFrame is already defined in the API.
错误信息...
./JFrame.java:1: JFrame is already defined in this compilation unit
import javax.swing.JFrame;
...表明 ./JFrame.java 与 radiobutton 存在于同一个包中.
...reveals that ./JFrame.java exists in the same package as radiobutton.
(作为旁注，我想提一下，根据 Java 编码约定，您应该始终以大写字母开头类名.)
(As a side note I want to mention that according to the Java coding conventions, you should always start your class names with a capital letter.)
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