编译器API

JavaCompiler

编译文件

JavaCompiler javaCompiler = ToolProvider.getSystemJavaCompiler();javaCompiler.run(null,null,null,"path");

编译字符串

private static Class<?> compile(String className, String javaCodes) throws URISyntaxException {    class JavaSourceFromString extends SimpleJavaFileObject {        private final String src;        public JavaSourceFromString(String className, String code) throws URISyntaxException {            super(URI.create("string:///" + className.replace('.', '/')                    + ".java"), JavaFileObject.Kind.SOURCE);            this.src = code;        }        public String getCode() {return src;}        @Override        public CharSequence getCharContent(boolean ignoreEncodingErrors) {            return src;        }    }    //将字符串包装为SimpleJavaFileObject对象    JavaSourceFromString srcObject = new JavaSourceFromString(className, javaCodes);    System.out.println(srcObject.getCode());    Iterable<? extends JavaFileObject> fileObjects = Arrays.asList(srcObject);    JavaCompiler compiler = ToolProvider.getSystemJavaCompiler();    StandardJavaFileManager fileManager = compiler.getStandardFileManager(null, null, null);    DiagnosticCollector<JavaFileObject> diagnosticCollector = new DiagnosticCollector<JavaFileObject>();    //设置编译的输出目录，并包装在options中    String flag = "-d";    String outDir = "";    try {        File classPath = new File(Thread.currentThread().getContextClassLoader().getResource("").toURI());        outDir = classPath.getAbsolutePath() + File.separator;        System.out.println(outDir);    } catch (URISyntaxException e1) {        e1.printStackTrace();    }    Iterable<String> options = Arrays.asList(flag, outDir);    //JavaCompiler.getTask方法：以future的任务形式(多线程)，来执行编译任务    // 第一个参数：额外输出流，null表示默认使用system.err    // 第二个参数：文件管理器，null表示编译器标准文件管理器    // 第三个参数：诊断监听器，null表示使用编译器默认方法来报告诊断信息    // 第四个参数：编译器参数，null表示无参数    // 第五个参数：需要经过annotation处理的类名，null表示没有类需要annotation处理    // 第六个参数：待编译的类    JavaCompiler.CompilationTask task =            compiler.getTask(null, fileManager, diagnosticCollector, options, null, fileObjects);    //等待编译结束    boolean result = task.call();    if (result) {        try {            return Class.forName(className);        } catch (ClassNotFoundException e) {            e.printStackTrace();        }    }    else    {        //print the Diagnostic's information        for  (Diagnostic diagnostic : diagnosticCollector                .getDiagnostics())        {            System.out.println("Error on line: "                    + diagnostic.getLineNumber() + "; URI: "                    + diagnostic.getSource().toString());        }    }    return null;}
String sourceCode = """public class HelloWorld {    public static void main(String[] args) {        System.out.println("hello world");    }}""";Class<?> klass = compile("HelloWorld", sourceCode);Method method = klass.getDeclaredMethod("main", String[].class);method.invoke(null, new Object[]{new String[]{}}); // print hello world

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