如何在Java

Question

我正在尝试动态编译并运行一些Java代码。 Java代码包含一些使用第三方jar（例如sikuli）的代码。当我在类路径中添加jar的绝对路径时，编译成功。然后，我尝试使用classloader执行代码，但是对于jar中存在的类，却没有找到类定义错误。谁能建议我任何解决方案。

请参考以下示例

嗨，我正在尝试动态编译Java代码（其中包含来自第三方jars中的类，即依赖项）并执行相同的代码，但对我不起作用。

Ex：如果我想执行一个简单的Java代码（System.out.println），它可以正常工作，但是如果我添加了任何第三方jar文件（例如：selenium）。它将引发未找到符号的错误。

 import java.io.File;
    import java.io.FileWriter;
    import java.io.IOException;
    import java.io.Writer;
    import java.net.URL;
    import java.net.URLClassLoader;
    import java.util.ArrayList;
    import java.util.Arrays;
    import java.util.List;
    import javax.tools.Diagnostic;
    import javax.tools.DiagnosticCollector;
    import javax.tools.JavaCompiler;
    import javax.tools.JavaFileObject;
  javax.tools.StandardJavaFileManager;
    import javax.tools.ToolProvider;

    public class InlineCompiler {

        public static void main(String[] args) {
            StringBuilder sb = new StringBuilder(64);
            sb.append("package testcompile;\n");
      sb.append("import org.sikuli.script.*;\n");
            sb.append("public class HelloWorld implements inlinecompiler.InlineCompiler.DoStuff {\n");
            sb.append("    public void doStuff() {\n");
 sb.append("Screen s = new Screen();\n");
            sb.append("        System.out.println(\"Hello world\");\n");
            sb.append("    }\n");
            sb.append("}\n");

            File helloWorldJava = new File("testcompile/HelloWorld.java");
            if (helloWorldJava.getParentFile().exists() || helloWorldJava.getParentFile().mkdirs()) {

                try {
                    Writer writer = null;
                    try {
                        writer = new FileWriter(helloWorldJava);
                        writer.write(sb.toString());
                        writer.flush();
                    } finally {
                        try {
                            writer.close();
                        } catch (Exception e) {
                        }
                    }

                    /** Compilation Requirements *********************************************************************************************/
                    DiagnosticCollector<JavaFileObject> diagnostics = new DiagnosticCollector<JavaFileObject>();
                    JavaCompiler compiler = ToolProvider.getSystemJavaCompiler();
                    StandardJavaFileManager fileManager = compiler.getStandardFileManager(diagnostics, null, null);

                    // This sets up the class path that the compiler will use.
                    // I've added the .jar file that contains the DoStuff interface within in it...
                    List<String> optionList = new ArrayList<String>();
                    optionList.add("-classpath");
                    optionList.add(System.getProperty("java.class.path") + ";sikuli.jar");

                    Iterable<? extends JavaFileObject> compilationUnit
                            = fileManager.getJavaFileObjectsFromFiles(Arrays.asList(helloWorldJava));
                    JavaCompiler.CompilationTask task = compiler.getTask(
                        null, 
                        fileManager, 
                        diagnostics, 
                        optionList, 
                        null, 
                        compilationUnit);
                    /********************************************************************************************* Compilation Requirements **/
                    if (task.call()) {
                        /** Load and execute *************************************************************************************************/
                        System.out.println("Yipe");
                        // Create a new custom class loader, pointing to the directory that contains the compiled
                        // classes, this should point to the top of the package structure!
                        URLClassLoader classLoader = new URLClassLoader(new URL[]{new File("./").toURI().toURL()});
                        // Load the class from the classloader by name....
                        Class<?> loadedClass = classLoader.loadClass("testcompile.HelloWorld");
                        // Create a new instance...
                        Object obj = loadedClass.newInstance();
                        // Santity check
                        if (obj instanceof DoStuff) {
                            // Cast to the DoStuff interface
                            DoStuff stuffToDo = (DoStuff)obj;
                            // Run it baby
                            stuffToDo.doStuff();
                        }
                        /************************************************************************************************* Load and execute **/
                    } else {
                        for (Diagnostic<? extends JavaFileObject> diagnostic : diagnostics.getDiagnostics()) {
                            System.out.format("Error on line %d in %s%n",
                                    diagnostic.getLineNumber(),
                                    diagnostic.getSource().toUri());
                        }
                    }
                    fileManager.close();
                } catch (IOException | ClassNotFoundException | InstantiationException | IllegalAccessException exp) {
                    exp.printStackTrace();
                }
            }
        }

        public static interface DoStuff {

            public void doStuff();
        }

    }