Jython,只使用Java中的Python方法？

Question

在阅读和使用本文时,它假定我们有一个完整的对象定义,其中包含从python到java的类和映射(代理)对象.

是否有可能只从python中的一段代码中导入一个方法(未在类中定义,但使用内部python类),而不将其包装在类定义中(不使用上述工厂范例).

我想from myPyFile import myMethod从java 做一些,然后直接从java使用myMethod(也许作为静态方法？)？但是,如果这是可能的,我没有找到任何关于如何做的线索(文章中描述的界面东西可能仍然需要告诉Java如何使用myMethod？)

最好的祝福.

编辑:我现在正在处理Jython 2.5.2,所以它可能依赖于版本,将来会更容易？

编辑:下面回复丹尼尔:

这是一个示例代码,用于重现我得到的错误,并从您有用的回复中获得一个有效的示例!

(好吧,在从yield -ed Python/Jython结果返回Java对象的映射中添加一些其他问题)

(@Joonas,对不起,我修改了我的代码,现在我无法退回到以前的错误)

import org.python.core.Py;
import org.python.core.PyList;
import org.python.core.PyTuple;
import org.python.core.PyObject;
import org.python.core.PyString;
import org.python.core.PySystemState;
import org.python.util.PythonInterpreter;

interface MyInterface {
    public PyList getSomething(String content, String glue, boolean bool);
}
class MyFactory {

    @SuppressWarnings("static-access")
    public MyFactory() {
        String cmd = "from mymodule import MyClass";
        PythonInterpreter interpreter = new PythonInterpreter(null, new PySystemState());

        PySystemState sys = Py.getSystemState();
        sys.path.append(new PyString("C:/jython2.5.2/Lib"));

        interpreter.exec(cmd);
        jyObjClass = interpreter.get("MyClass");
    }

    public MyInterface createMe() {
        PyObject myObj = jyObjClass.__call__();
        return (MyInterface)myObj.__tojava__(MyInterface.class);
    }

    private PyObject jyObjClass;
}


public class Main {

    public static void main(String[] args) {

    /*
// with only :
    PythonInterpreter interpreter = new PythonInterpreter();

     i get : 
Exception in thread "main" Traceback (most recent call last):
  File "<string>", line 1, in <module>
LookupError: no codec search functions registered: can't find encoding 'iso8859_1'

which is probably due to the : 
#!/usr/bin/env python
# -*- coding: latin-1 -*-

// yes i am from France, so my - sorry for that - bad english ;) and have to deal with non 127 ascii chars :)
     */

    PythonInterpreter interpreter = new PythonInterpreter(null, new PySystemState());

    PySystemState sys = Py.getSystemState();
    sys.path.append(new PyString("C:/jython2.5.2/Lib"));

    interpreter.exec("from mymodule import getSomething"); 
    PyObject tmpFunction = interpreter.get("getSomething"); 
    System.err.println(tmpFunction.getClass()); 
    MyInterface i = (MyInterface) tmpFunction.__tojava__(MyInterface.class); 
    System.err.println(i.getSomething("test", " - ", true));
    for (Object x : i.getSomething("test", " - ", true)) {
        System.out.println(x);
        // How can i get back an equivallent of the Python _"for (a, b) in getSomething:"_ 
        // with _"a"_ being PyUnicode or better String, and _"b"_ being boolean ?
    }

    // ^^ so adapting Daniel Teply solution works ! Thanks to him... 
    // BTW the part below did not work : but i may have missed or/and also mixed many things :/
    // i feel Jython damned hard to dive in :/ 
    // and really hope that the sample that i post and answers that i get will help others to swim!

    try {
        MyFactory factory = new MyFactory();
        MyInterface myobj = factory.createMe();

        PyList myResult = myobj.getSomething("test", " - ", true);
        System.out.println(myResult);
    }
    catch (Exception e) {
        System.out.println(e);
        // produce a : java.lang.ClassCastException: org.python.core.PySingleton cannot be cast to MyInterface
        // EDIT : see below last edit, this error may be due to my forgotten heritage from interface in the python code!
    }

    System.exit(-1);
    }
}

Python部分:(mymodule.py)

#!/usr/bin/env python
# -*- coding: latin-1 -*-

class MyClass:
    def __init__(selfself):
        pass
    def getSomething(self, content, glue = '', bool = True):
        for x in range(5):
            yield (glue.join(map(str, (content, x, chr(97 + x))))), bool
        #return list()

def getSomething(content, glue = '', bool = True):
    print "test"
    myclass = MyClass()
    return list(myclass.getSomething(content, glue, bool))

def main():
    test()

if __name__ == "__main__":
    main()

编辑:

部分回答我自己,因为内部问题(内评论):
(其实我觉得我的答案和代码是丑陋,但它的工作原理,似乎是确定以非元组,我不知道是否有更好的Jythonic路做它,如果是这样,我真的很感兴趣:))

for (Object x : i.getSomething("test", " - ", true)) {
    System.out.println(x);
    // How can i get back an equivallent of the Python _"for (a, b) in getSomething:"_ 
    // with _"a"_ being PyUnicode or better String, and _"b"_ being boolean ?

    // answering myself here :
    PyTuple mytuple = (PyTuple) x; // casting back x as PyTuple, can we have a java equivalent to _`(a, b) = x_ ? not sure...
    PyObject a = mytuple.__getitem__(0);
    PyObject b = mytuple.__getitem__(1);
    String aS = a.toString(); // mapping a unicode python string to java is as simple?
    boolean bB = b.toString().toLowerCase().equals("true");
    System.out.println(mytuple + "[" + aS + "][" + b + "][" + bB + "]");

编辑:

回答自己关于"产生一个:"的部分java.lang.ClassCastException:org.python.core.PySingleton无法转换为MyInterface" ...我的大多数误解和错误都归因于我忘记了这一点从Python部分处理Java!(参见上面的代码,我对此事进行了不修正,因为这不是我的主要问题,而且在实际形式中,这是关于这个主要问题的工作答案,非常感谢Daniel和帮我理解的Joonas.所以对于工厂范例,不要忘记在Python文件中添加足够的导入:

from testjython.interfaces import MyInterface #// defining method inside a MyInterface.java

class MyClass(MyInterface):
    [...]

我遇到的另一个困难是正确处理导入和包.顺便说一句,将此代码添加到上层代码将产生一个TypeError:无法转换为org.python.core.PyList但这是另一个问题......

Answer 1

您可以使用它PyObject.__call__(Object... args)来调用任何可调用的Python对象.您可以从java端获取表示函数的PyFunction,就像获取python employee类一样.

Alternativeley,您可以通过调用__tojava__(Interface.class)从Python解释器检索的函数将其隐藏在java端的单个方法接口后面.详细示例(实际测试!):python文件:

def tmp():
    return "some text"

Java的:

public interface I{
    public String tmp();
}

public static void main(String[] args) {
    PythonInterpreter interpreter = new PythonInterpreter();
    interpreter.exec("from test import tmp");
    PyObject tmpFunction = interpreter.get("tmp");
    System.err.println(tmpFunction.getClass());
    I i = (I) x.__tojava__(I.class);
    System.err.println(i.tmp());

}

输出:

class org.python.core.PyFunction
some text