Jpype：在jar中导入类时出现ModuleNotFoundError

Posted 2023-02-24

【中文标题】Jpype：在jar中导入类时出现ModuleNotFoundError

【英文标题】：Jpype: ModuleNotFoundError when import classes in jar

【发布时间】：2021-11-13 13:12:55

【问题描述】：

问题

当我将-Djava.class.path 设置为目录"jars/*" 时，我得到了ModuleNotFoundError: No module named 'spoon'。

项目结构

utils
├── __init__.py
├── jars
│   └── spoon-core-9.2.0-beta-4.jar
└── parse_utils.py

# parse_utils.py

import jpype
import jpype.imports
from jpype.types import *

JARS_PATH = 'jars/*'
jpype.startJVM(jpype.getDefaultJVMPath(),  '-Djava.class.path=' + JARS_PATH)

import spoon.Launcher as Launcher

我尝试过的

JClass 和 JPackage

我在 *** Jpype import cannot find module in jar 发现了类似的问题，我尝试了最佳答案但失败了。

Launcher = jpype.JPackage('spoon').Launcher  # AttributeError: Java package 'spoon' is not valid

Launcher = jpype.JClass('spoon.Launcher')  # TypeError: Class spoon.Launcher is not found

Launcher = jpype.JClass("java.lang.Class").forName('spoon.Launcher') # java.lang.ClassNotFoundException: java.lang.ClassNotFoundException: spoon.Launcher

使用jar路径

JARS_PATH = 'jars/spoon-core-9.2.0-beta-4.jar'

我得到了：

Traceback (most recent call last):
  File "ClassLoader.java", line 357, in java.lang.ClassLoader.loadClass
  File "Launcher.java", line 338, in sun.misc.Launcher$AppClassLoader.loadClass
  File "ClassLoader.java", line 424, in java.lang.ClassLoader.loadClass
  File "URLClassLoader.java", line 381, in java.net.URLClassLoader.findClass
java.lang.ClassNotFoundException: java.lang.ClassNotFoundException: com.martiansoftware.jsap.JSAPException

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "org.jpype.pkg.JPypePackage.java", line -1, in org.jpype.pkg.JPypePackage.getObject
  File "Class.java", line 348, in java.lang.Class.forName
  File "Class.java", line -2, in java.lang.Class.forName0
Exception: Java Exception

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "/Users/audrey/Documents/GitHub/xiaoven/codegex/utils/parse_utils.py", line 16, in <module>
    import spoon.Launcher as Launcher
  File "<frozen importlib._bootstrap>", line 991, in _find_and_load
  File "<frozen importlib._bootstrap>", line 971, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 914, in _find_spec
  File "/usr/local/Caskroom/miniconda/base/envs/codegex/lib/python3.8/site-packages/jpype/imports.py", line 194, in find_spec
    if not hasattr(base, parts[2]):
java.lang.NoClassDefFoundError: java.lang.NoClassDefFoundError: com/martiansoftware/jsap/JSAPException

【参考方案1】：

见this link:

我会先检查罐子是否在路径中被拾起。

import jpype
jpype.startJVM(classpath="jars/*")
print(jpype.java.lang.System.getProperty("java.class.path"))

我的猜测是您的测试代码中存在语法错误，或者勺子 jar 缺少一些依赖项，但在您的示例中没有任何突出之处。 jars 目录中是否有所需的 jar 依赖项，包括 com.martiansoftware.jsap.JSAPException？

我根据错误日志（或IDEA项目视图下的External Libraries列表）手动下载缺失的jar后，成功导入spoon类。