Question

我正在编写一个游戏，其中玩家通过更改关卡中的对象的源代码来导航谜题。为了做到这一点，我有一个扩展JPanel的类，它将使用来自播放器的已编辑源代码进行编写。我的问题是如何使用java实用程序或使用beanshell从文本文件编译类文件？文本文件包含纯java，但游戏的玩家可能会导致编译或运行时错误（例如无限循环），我希望能够捕获所述错误并提醒玩家。

Answer 1

听起来很棒，但动态编译类并让它们执行需要相当多的工作。有一个名为Janino的库（用他们自己的话说）：

Janino是一款超小型超高速Java™编译器。它不仅可以将一组源文件编译为一组类文件（如JAVAC），还可以在内存中编译Java™表达式，块，类主体或源文件，加载字节码并直接在同一JVM中执行

通过将与实际编译和运行动态代码相关的工作委托给Janino，您可以专注于实际的游戏逻辑。

Answer 2

如果您不想使用外部库，则需要编写自己的ClassLoader。我找到的最简单的实现是here。

/*
 * Copyright 2008-2010 Sun Microsystems, Inc.  All Rights Reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Sun designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Sun in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
 * CA 95054 USA or visit www.sun.com if you need additional information or
 * have any questions.
 */

package com.sun.btrace;

/**
 * A simple class loader that loads from byte buffer.
 *
 * @author A. Sundararajan
 */
final class MemoryClassLoader extends ClassLoader {
    MemoryClassLoader() {
        this(null);
    }

    MemoryClassLoader(ClassLoader parent) {
        super(parent);
    }

    Class loadClass(String className, byte[] buf) 
        throws ClassNotFoundException {
        return defineClass(className, buf, 0, buf.length);
    }
}

Answer 3

您可以考虑使用JVM支持的脚本语言（如Groovy）作为动态部分。

从.txt文件编译.class文件

3 个答案: