Question

我正在使用 Python 3.4 。

我有一个Python脚本myscript.py：

import sys
def returnvalue(str) :
    if str == "hi" :
        return "yes"
    else :
        return "no"
print("calling python function with parameters:")
print(sys.argv[1])
str = sys.argv[1]
res = returnvalue(str)
target = open("file.txt", 'w')
target.write(res)
target.close()

我需要从java类PythonJava.java

调用这个python脚本

public class PythonJava 
{
    String arg1;
    public void setArg1(String arg1) {
        this.arg1 = arg1;
    }
public void runPython() 
    { //need to call myscript.py and also pass arg1 as its arguments.
      //and also myscript.py path is in C:\Demo\myscript.py
}

我通过创建runPython()的对象

从另一个Java类调用PythonJava

obj.setArg1("hi");
...
obj.runPython();

我尝试了很多方法，但没有一个方法正常工作。我使用了Jython和ProcessBuilder，但脚本没有写入file.txt。你能建议一种正确实施的方法吗？

Answer 1

你看过这些吗？他们提出了不同的做法：

Call Python code from Java by passing parameters and results

How to call a python method from a java class?

简而言之，一个解决方案可能是：

public void runPython() 
{ //need to call myscript.py and also pass arg1 as its arguments.
  //and also myscript.py path is in C:\Demo\myscript.py

    String[] cmd = {
      "python",
      "C:/Demo/myscript.py",
      this.arg1,
    };
    Runtime.getRuntime().exec(cmd);
}

编辑：只需确保将变量名称从str更改为其他名称，如cdarke

所述

您的python代码（将str更改为其他内容，例如arg并指定文件路径）：

def returnvalue(arg) :
    if arg == "hi" :
        return "yes"
    return "no"
print("calling python function with parameters:")
print(sys.argv[1])
arg = sys.argv[1]
res = returnvalue(arg)
print(res)
with open("C:/path/to/where/you/want/file.txt", 'w') as target:  # specify path or else it will be created where you run your java code
    target.write(res)

Answer 2

可以使用以下简单方法通过Java从Argument调用python并在java控制台中打印python输出：

ApiRestTest

Answer 3

下面是带有三个示例参数的python方法，以后可以通过java调用它们。

#Sample python method with arguments
import sys
 
def getDataFromJava(arg1,arg2,arg3):
       
    arg1_val="Hi"+arg1
    arg2_val=arg2
    arg3_val=arg3
   
    print(arg1_val)
    print(arg2_val)
    print(arg3_val)
    
    return arg1_val,arg2_val,arg3_val
    
    
    
arg1 = sys.argv[1]
arg2 = sys.argv[2]
arg3 = sys.argv[3]

getDataFromJava(arg1,arg2,arg3)

下面是使用三个示例参数调用上述方法的Java代码，并通过InputStreamReader读取java中python脚本的控制台输出。

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class Test1 {
    
    public static String s;
    
    public static void main(String[] args) throws IOException {
        
        
        
        String pathPython = "Path_to_the_file\\test.py";
        String [] cmd = new String[5];
        cmd[0] = "python";
        cmd[1] = pathPython;
        cmd[2] = "arg1";
        cmd[3] = "arg2";
        cmd[4] = "arg3";
        Runtime r = Runtime.getRuntime();
        
        Process p = r.exec(cmd);
        BufferedReader in = new BufferedReader(new InputStreamReader(p.getInputStream()));
        while((s=in.readLine()) != null){
            System.out.println(s);
            }
        
        
    }

}

如何使用Java类中的参数调用Python脚本

3 个答案: