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Java calls Python

巴扎黑
Release: 2016-12-09 10:31:11
Original
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今天遇到Java调用一个Python脚本的问题,纠结了大半天,遇到各种问题。网上搜索的大部分都是用jython,但是我想要调用的python脚本里有import urllib,这个urllib也不是什么第三方扩展库,在python的安装path下的Lib下就有,在python命令行下肯定是能找到的。但是用jython的话,sys的path里面就太少了。示例代码:

import org.python.core.Py;
import org.python.core.PySystemState;
import org.python.util.PythonInterpreter;
public class Test3 {
    /**
     * @param args
     */
    public static void main(String[] args) {
        
        PythonInterpreter interpreter = new PythonInterpreter();  
        
        PySystemState sys = Py.getSystemState(); 
        //sys.path.add("D:\\jython2.5.2\\Lib");
        System.out.println(sys.path.toString()); 
        
        interpreter.exec("print 'hello'");  
        
        interpreter.exec("import sys");
        interpreter.exec("print sys.path");
        
//        interpreter.exec("import urllib");
//        interpreter.exec("print urllib");
    }
}
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打印出来的sys.path为:

Txt代码

['D:\\eclipse_jee_workspace\\ZLabTest\\lib\\Lib', '__classpath__', '__pyclasspath__/']

这儿就只有eclipse的工程的路径包含了,所以当然找不到urllib啦。而在命令行下打印sys.path为:


用jython差的lib库少太多了,也懒得用类似sys.path.add("D:\\jython2.5.2\\Lib");一个一个加了,所以果断放弃jython。

然后查到可以用Runtime.getRuntime().exec("python test.py");示例代码如下:

import java.io.BufferedReader;
import java.io.InputStreamReader;
public class Test5 {
        public static void main(String[] args){
                try{
                        System.out.println("start");
                        Process pr = Runtime.getRuntime().exec("python test.py");
                        
                        BufferedReader in = new BufferedReader(new
                                InputStreamReader(pr.getInputStream()));
                        String line;
                        while ((line = in.readLine()) != null) {
                            System.out.println(line);
                        }
                        in.close();
                        pr.waitFor();
                        System.out.println("end");
                } catch (Exception e){
                            e.printStackTrace();
                        }
                }
}
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test.py的文件内容为:

Python代码

import sys  
import urllib  
print "hello"  
print sys.path
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java程序运行的结果为:

Txt代码

start  
hello  
['D:\\eclipse_jee_workspace\\ZLabTest', 'C:\\Windows\\system32\\python27.zip', 'D:\\Python27\\DLLs', 'D:\\Python27\\lib', 
'D:\\Python27\\lib\\plat-win', 'D:\\Python27\\lib\\lib-tk', 'D:\\Python27', 'D:\\Python27\\lib\\site-packages']
end
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 这就比较对了。但是中途还是遇到了很多问题,在Eclipse中运行上面的java程序抛出异常:

java.io.IOException: Cannot run program "python": CreateProcess error=2, ϵͳÕҲ»µ½ָ¶

at java.lang.ProcessBuilder.start(ProcessBuilder.java:460)

at java.lang.Runtime.exec(Runtime.java:593)

at java.lang.Runtime.exec(Runtime.java:431)

at java.lang.Runtime.exec(Runtime.java:328)

at com.mysrc.Test5.main(Test5.java:10)

Caused by: java.io.IOException: CreateProcess error=2, ϵͳÕҲ»µ½ָ¶

at java.lang.ProcessImpl.create(Native Method)

at java.lang.ProcessImpl.(ProcessImpl.java:81)

at java.lang.ProcessImpl.start(ProcessImpl.java:30)

at java.lang.ProcessBuilder.start(ProcessBuilder.java:453)

... 4 more

就是没法调用python程序,而如果是在命令行下用javac编译,然后java执行的话肯定是对的。怎么才能在Eclipse里也能正常运行了,网上查了半天,在run configurations->environment新建一个PATH,值设为安装的python的路径,再运行就OK了。


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