回到主要班级 [英] Going back to main class
问题描述
这里我有我的终端项目，在终端内部，我可以输入创建，这将带我进入创建提示，在那里我可以创建一个程序。我现在的问题是我无法返回Main类（我可以选择一个命令来运行）。我有想法尝试使用System.exit（0）;但是，正如我没有意识到的那样，它只会杀死整个程序。如果有人能帮助我，我的文件在下面。如果需要，我可以发布任何其他文件。
Here I have my terminal project, and inside the terminal, I can type "create", which will take me to the create prompt, where I can create a program. My problem right now is the fact that I can't get back to the Main class (Where I can select a command to run). I had the idea of trying to use the System.exit(0); but, as I didn't realise, it just kills the entire program. If anyone is able to help me, my file is below. I can post any other files if requested.
import java.util.*;
import java.io.*;
public class commandCreate {
boolean _active = true;
String _username = System.getProperty("user.name").toLowerCase();
String _os = System.getProperty("os.name").trim().toLowerCase();
String fileName, create, option;
public commandCreate() {
try {
while(_active) {
System.out.print(_username + "@" + _os + ":~/create$ ");
Scanner kbd = new Scanner(System.in);
String userLine = kbd.nextLine();
if(java.util.regex.Pattern.matches(".*\\S\\s+\\S.*", userLine)) {
Scanner read = new Scanner(userLine);
option = read.next();
fileName = read.next();
}
FileWriter create = new FileWriter(new File("Created Files/" + fileName + ".java"));
if(userLine.equals(option + " " + fileName)) {
if(option.equals("-a")) {
// Option = -a, creates standard file with main class.
create.write("public class " + fileName + " {\n");
create.write(" public static void main(String[] args) {\n");
create.write(" System.out.println(\"Welcome to your new program!\");\n");
create.write(" }\n");
create.write("}");
} else if(option.equals("-c")) {
// Option = -c , creates standard file with overloaded constructor & main class.
create.write("public class " + fileName + " {\n");
create.write(" public " + fileName + "() {\n");
create.write(" System.out.println(\"Welcome to your new program!\");\n");
create.write(" }\n");
create.write("\n");
create.write(" public static void main(String[] args) {\n");
create.write(" new " + fileName + "();\n");
create.write(" }\n");
create.write("}");
} else if(option.equals("-j")) {
// Option = -j, creates GUI within constructor w/ single JLabel.
create.write("import javax.swing.*;\n");
create.write("import java.awt.*;\n");
create.write("import java.awt.event.*;\n");
create.write("\n");
create.write("public class " + fileName + " extends JFrame {\n");
create.write(" private static final int HEIGHT = 50;\n");
create.write(" private static final int WIDTH = 400;\n");
create.write("\n");
create.write(" private JLabel welcomeJ;\n");
create.write("\n");
create.write(" public " + fileName + "() {\n");
create.write(" super(\"Welcome to your program - " + fileName + "\");\n");
create.write(" Container pane = getContentPane();\n");
create.write(" setLayout(new FlowLayout());\n");
create.write("\n");
create.write(" welcomeJ = new JLabel(\"Welcome To Your Program!\", SwingConstants.CENTER);\n");
create.write("\n");
create.write(" pane.add(welcomeJ);\n");
create.write("\n");
create.write(" setSize(WIDTH, HEIGHT);\n");
create.write(" setVisible(true);\n");
create.write(" setResizable(false);\n");
create.write(" setDefaultCloseOperation(EXIT_ON_CLOSE);\n");
create.write(" }\n");
create.write("\n");
create.write(" public static void main(String[] args) {\n");
create.write(" new " + fileName + "();\n");
create.write(" }\n");
create.write("}");
}
} else if(userLine.equalsIgnoreCase("help")) {
System.out.println("Commands");
System.out.println(" Syntax: [-option] [filename]");
System.out.println(" -a [filename] [Program: main class]");
System.out.println(" -c [filename] [Program: overloaded constructor, main class]");
System.out.println(" -j [filename] [Program: GUI: overloaded constructor, main class]");
} else if(userLine.equalsIgnoreCase("exit")) {
System.exit(0);
} else {
System.out.println("Error in syntax. Please review the \"help\" menu");
}
create.close();
}
} catch(IOException e) {
System.out.println("There was an error: " + e);
} catch(InputMismatchException ex) {
System.out.println("There was an error: " + ex);
}
}
public static void main(String[] args) {
new commandCreate();
}
}
推荐答案
简单的答案是让 commandCreate 构造函数返回，或抛出/传播异常。实际上，我认为如果用户输入EOF，这种情况就已经发生了。
The simple answer is to get the commandCreate constructor to return, or throw / propagate an exception. Indeed, I think this will happen already if the user enters an EOF.
（你的代码还有很多其他问题，但如果你认为这样做可能会更好但是我会指出，commandCreate或CommandCreate对于类名来说是一个非常糟糕的选择。类名通常是名词。）
(There are numerous other things wrong with your code, but it is probably better if you figure that out for yourself. I will point out however, that "commandCreate" or "CommandCreate" is a really poor choice for a class name. A class name is typically a noun.)
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