在Javac中使用Runtime＃exec（）-沒有類文件

Question

下面MyCompilingUtility.java創建一個文件（一個Java類- AutoGenerated.java ）通過PrintWriter 。 此類僅具有帶有打印語句的Main方法。 其次，該程序調用javac AutoGenerated.java 。

public static void main(String args[]) throws IOException, 
   FileNotFoundException, UnsupportedEncodingException {
    createFile("AutoGenerated.java");
    compile("AutoGenerated.java");
}

public static void compile(String fileName) throws IOException {
    final String javacPath = "C:/Program Files/Java/jdk1.7.0_51/bin/javac.exe";
    Runtime rt = Runtime.getRuntime();
    final String compileCmd = javacPath + " " + fileName;
    rt.exec(compileCmd);
}

public static void createFile(String fileName) throws FileNotFoundException,
       UnsupportedEncodingException  {
    PrintWriter writer = new PrintWriter(fileName, "UTF-8");
    writer.println("public class AutoGenerated");
    writer.println("{");
    writer.println("  public static void main(String [] args)");
    writer.println("  {");
    writer.println("    System.out.println(\"Hello from AutoGenerated World\")");
    writer.println("  }");
    writer.println("}");
    writer.close();
}

但是，在運行javac MyCompilingUtility.java && java MyCompilingUtility ，沒有生成AutoGenerated.class文件。

這是為什么？

Answer 1

你錯過了; 在......的最后

writer.println("    System.out.println(\"Hello from AutoGenerated World\");");
                                                                          ^

編譯器根本無法編譯它。