Java API¶
The Java API provides facilities to use Python classes and objects from Java code. For examples of how to use it, see the demo app.
Summary¶
- If necessary, call Python.start().
- Call Python.getInstance() to get the interface to Python.
- Call getModule() or getBuiltins() to get a PyObject representing a Python module.
- Use the PyObject methods to access the module’s functions, classes and other objects.
Examples¶
The following all assume py is a Python instance.
Modules, classes, attributes and methods:
# Python code // Java equivalent
import zipfile PyObject zipfile = py.getModule("zipfile")
zf = zipfile.ZipFile( PyObject zf = zipfile.callAttr("ZipFile",
"example.zip") "example.zip");
zf.debug = 2 zf.put("debug", 2);
zf.comment zf.get("comment");
zf.write( zf.callAttr("write",
"filename.txt", "filename.txt",
compress_type=zipfile.ZIP_STORED) new Kwarg("compress_type",
zipfile.get("ZIP_STORED")));
Built-in types and functions:
# Python code // Java equivalent
PyObject builtins = py.getBuiltins();
l = [2, 1, 3] PyObject l = builtins.callAttr("list", 2, 1, 3);
sorted(l) builtins.callAttr("sorted", l);
l[0] l.callAttr("__getitem__", 0);
l[0] = 42 l.callAttr("__setitem__", 0, 42);
d = {1: "a", 2: "b"} PyObject d = builtins.callAttr("dict");
d.callAttr("__setitem__", 1, "a");
d.callAttr("__setitem__", 2, "b");
Type conversion:
# Python code // Java equivalent
import sys PyObject sys = py.getModule("sys");
ms = sys.maxsize int ms = sys.get("maxsize").toJava(int.class);
version = sys.version String version = sys.get("version").toString()