Java API¶
The Java API provides facilities to use Python classes and objects from Java code.
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")));
Primitive types:
# Python code // Java equivalent
import sys PyObject sys = py.getModule("sys");
sys.maxsize sys.get("maxsize").toLong();
sys.version sys.get("version").toString();
sys.is_finalizing() sys.callAttr("is_finalizing").toBoolean();
Container types:
# Python code // Java equivalent
import sys PyObject sys = py.getModule("sys");
sys.version_info[0] sys.get("version_info").asList().get(0).toInt();
import os PyObject os = py.getModule("os");
os.environ["HELLO"] os.get("environ").asMap().get("HELLO").toString();
os.environ["HELLO"] = "world" os.get("environ").asMap().put(
PyObject.fromJava("HELLO"),
PyObject.fromJava("world"));
For more examples, see the demo app.