在运行时编写和实现新的 Java 类文件

发布于 2024-10-27 15:47:34 字数 1478 浏览 3 评论 0 原文

是否有可能以某种方式将新的 Java 类“导入”到正在运行的程序中并使用它？

我可以让程序创建一个“.java”类型的新文件，然后将其包含在项目文件中并引用它，而无需重新启动程序吗？

以下是我的意思的一个示例：

import java.io.*;

public class Program {

File JClass = new File("JClass.java");
public static BufferedWriter out = null;

    public static void main(String[] args) {
        try {
            out = new BufferedWriter(new FileWriter("JClass.java"));
            out.write("public abstract class JClass {");
            out.newLine();
            out.newLine();
            out.write("    public void printSomething(String a) {");
            out.newLine();
            out.write("        System.out.println(a);");
            out.newLine();
            out.write("    }");
            out.newLine();
            out.write("}");
            out.close();
        } catch (IOException e)
        {
            System.exit(-1);
        }

        //Somehow import JClass.java as a class here

        JClass.printSomething("Yay! It worked!");
    }

}

生成的“JClass.java”文件：

public abstract class JClass {

    public void printSomething(String a) {
        System.out.println(a);
    }
}

同样，是否可以创建项目源文件之一的副本，编辑文件中的代码，然后以某种方式强制进行更改正在运行的程序？

目前我不太关心实际应用。我只是在探索与编程相关的不同想法。我也明白这有可能引发各种灾难。编辑正在运行的代码，并动态包含类（我不认为在构建项目时会像其他类那样检查错误）可能会产生非常不可预测的结果。我只是想尝试一下这个想法。

也就是说，如果有人有任何有用的警告或需要注意的事情，我将不胜感激。否则，如果人们不要回答“这是一个坏主意”或“有更简单更好的方法来解决问题”，我将不胜感激。我并不是想解决这个问题。我只是在探索这个想法。

那么，这可能吗？

原文

Is it possible to somehow 'import' a new Java class into a running program and make use of it?

Could I have a program create a new File of type '.java' and then include it in the project files and reference it without having to restart the program?

The following is an example of what I mean:

import java.io.*;

public class Program {

File JClass = new File("JClass.java");
public static BufferedWriter out = null;

    public static void main(String[] args) {
        try {
            out = new BufferedWriter(new FileWriter("JClass.java"));
            out.write("public abstract class JClass {");
            out.newLine();
            out.newLine();
            out.write("    public void printSomething(String a) {");
            out.newLine();
            out.write("        System.out.println(a);");
            out.newLine();
            out.write("    }");
            out.newLine();
            out.write("}");
            out.close();
        } catch (IOException e)
        {
            System.exit(-1);
        }

        //Somehow import JClass.java as a class here

        JClass.printSomething("Yay! It worked!");
    }

}

Resulting 'JClass.java' file:

public abstract class JClass {

    public void printSomething(String a) {
        System.out.println(a);
    }
}

Similarly, would it be possible to create a copy of one of the project's source files, edit the code in the file, and then somehow force the changes upon the running program?

I do not care so much about practical application at this point. I am merely exploring different ideas I have had relating to programming. I also understand that this is potential for all sorts of disaster. Editing running code, and including classes on the fly (which I don't imagine would be checked for errors as the other classes are when the project is built), could have very unpredictable results. I merely want to play around with the idea.

That said, if anyone has any HELPFUL warnings or things to look out for, I would appreciate them. Otherwise, I would appreciate if people kept from responding 'This is a bad idea' or 'there are easier and better ways to solve problems'. I am NOT trying to solve a problem with this. I am only exploring the idea.

So, is this possible?

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