在java中调用/执行python方法

柔情只为你懂 2021-05-12 11:54 581阅读 0赞

[http://sourceforge.net/projects/jython/][http_sourceforge.net_projects_jython]下载jython包，把其中的jython.jar添加到工程目录。

或者使用maven：

<dependency>
        <groupId>org.python</groupId>
        <artifactId>jython</artifactId>
        <version>2.7.0</version>
    </dependency>

1、 在java类中直接执行python语句

import javax.script.*;  
      
    import org.python.util.PythonInterpreter;  
      
    import java.io.*;  
    import static java.lang.System.*;  
    public class FirstJavaScript  
    {  
     public static void main(String args[])  
     {  
        
      PythonInterpreter interpreter = new PythonInterpreter();  
      interpreter.exec("days=('mod','Tue','Wed','Thu','Fri','Sat','Sun'); ");  
      interpreter.exec("print days[1];");  
        
        
     }//main  
    }

2、 在java中调用本机python脚本中的函数：

1）首先建立一个python脚本，名字为：my\_utils.py

def adder(a, b):  
        return a + b

2） 然后建立一个java类，用来测试：

import javax.script.*;  
      
    import org.python.core.PyFunction;  
    import org.python.core.PyInteger;  
    import org.python.core.PyObject;  
    import org.python.util.PythonInterpreter;  
      
    import java.io.*;  
    import static java.lang.System.*;  
    public class FirstJavaScript  
    {  
        public static void main(String args[])  
        {  
              
            PythonInterpreter interpreter = new PythonInterpreter();  
            interpreter.execfile("C:\\Python27\\programs\\my_utils.py");  
            PyFunction func = (PyFunction)interpreter.get("adder",PyFunction.class);  
      
            int a = 2010, b = 2 ;  
            PyObject pyobj = func.__call__(new PyInteger(a), new PyInteger(b));  
            System.out.println("anwser = " + pyobj.toString());  
      
      
        }//main  
    }

得到的结果是：anwser = 2012

3、使用java直接执行python脚本：

1）建立脚本input.py：

#open files  
      
    print 'hello'  
    number=[3,5,2,0,6]  
    print number  
    number.sort()  
    print number  
    number.append(0)  
    print number  
    print number.count(0)  
    print number.index(5)

2） 建立java类，调用这个脚本：

得到的结果是：

hello  
    [3, 5, 2, 0, 6]  
    [0, 2, 3, 5, 6]  
    [0, 2, 3, 5, 6, 0]  
    2  
    3

问题1：jython在eclipse控制台出现Failed to install '': java.nio.charset.UnsupportedCharsetException: cp0解决方法

在用jython在eclipse中开发的时候，控制台的输出可能会出现 console: Failed to install ”: java.nio.charset.UnsupportedCharsetException: cp0.   
这样一个错误，此时如果控制台的错误堆栈中有中文的时候，中文就会显示为乱码，解决办法为在要执行的代码上右键， Run As>Run Configurations,选择第二个页签Arguments,在VM arguments中添加：

\-Dpython.console.encoding=UTF-8

![Center][]

问题2：

console: Failed to install '': java.nio.charset.UnsupportedCharsetException: cp0.
    Exception in thread "main" ImportError: Cannot import site module and its dependencies: No module named site
    Determine if the following attributes are correct:
      * sys.path: ['...python\\jython\\2.7.0\\Lib', '__classpath__', '__pyclasspath__/']
        This attribute might be including the wrong directories, such as from CPython
      * sys.prefix:***\jython\2.7.0
        This attribute is set by the system property python.home, although it can
        be often automatically determined by the location of the Jython jar file
    
    You can use the -S option or python.import.site=false to not import the site module

解决：

import java.util.Properties;
    
    import org.python.util.PythonInterpreter;
    
    public class JpythonScript {
        public static void main(String args[]) {
    
            Properties props = new Properties();
            props.put("python.home", "path to the Lib folder");
            props.put("python.console.encoding", "UTF-8");
            
            props.put("python.security.respectJavaAccessibility", "false");
            
            props.put("python.import.site", "false");
    
            Properties preprops = System.getProperties();
    
            PythonInterpreter.initialize(preprops, props, new String[0]);
            PythonInterpreter interpreter = new PythonInterpreter();
            interpreter.exec("days=('mod','Tue','Wed','Thu','Fri','Sat','Sun'); ");
            interpreter.exec("print days[1];");
        }
    }

[http_sourceforge.net_projects_jython]: http://sourceforge.net/projects/jython/
[Center]: /images/20210511/7a004c1bce804c98b156a0e81e19642a.png