我试图使用
javax.script从
Java 6应用程序调用Jython：
import javax.script.ScriptEngine;
import javax.script.ScriptEngineManager;
import javax.script.ScriptException;
public class jythonEx
{
public static void main (String args[]) throws ScriptException
{
ScriptEngineManager mgr = new ScriptEngineManager();
ScriptEngine pyEngine = mgr.getEngineByName("python");
try {
pyEngine.eval("print \"Python - Hello,world!\"");
} catch (Exception ex) {
ex.printStackTrace();
}
}
}
这是导致NullPointerException：
java.lang.NullPointerException
at jythonEx.main(jythonEx.java:12)
有人有什么想法吗？
编辑：
感谢您的回应！我将jython.jar添加到类路径,并正常运行：
java -cp "./;jython.jar" jythonEx
解决方法
你必须先注册你的引擎.
从：ScriptEngineManager.getEngineByName：
[…] first searches for a ScriptEngineFactory that has been registered as a handle […] Returns null if no such factory was found
用户指南说to use it with JSR-223你必须：
As of Jython 2.5.1 an implementation of JSR 223 is bundled in jython.jar. Simply add jython to your CLASSPATH and ask for the python script engine.
你有没有这样做？
编辑关于你的评论：我想你应该开一个新问题,你会得到更好的答案.
