Java【代码 07】Java执行Python代码的3类5种情况测试（Java源码+Python源码举例）

1.why

python拥有的某些库要比Java强大，也拥有一些比Java更擅长的领域，python可以搭建后端让Java调用接口，但某些时候我们用到的python代码可能并不多也许只有一个算法，此时就需要以下方法了。

2.核心依赖

毫无疑问【自然是python的Java执行器了】

xml 复制代码

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

3.使用

3.1类型一【直接执行python代码】

java 复制代码

public class ExecPythonCode {
    public static void main(String[] args) {
        PythonInterpreter interpreter = new PythonInterpreter();
        interpreter.exec("a=[5,2,3,9,4,0];");
        // 此处python语句是3.x版本的语法
        interpreter.exec("print(sorted(a));"); 
        // 此处是python语句是2.x版本的语法
        interpreter.exec("print sorted(a);"); 
        interpreter.close();
    }
}

3.2类型二【执行python文件后获取返回结果】

无参数的python文件执行

java 复制代码

public class ExecPythonFile {
    public static void main(String[] args) {
        try {
            Process process = Runtime.getRuntime()
                    .exec("python D:\\PythonFile.py");
            BufferedReader in = new BufferedReader(new InputStreamReader(process.getInputStream()));
            String line = null;
            while ((line = in.readLine()) != null) {
                System.out.println(line);
            }
            in.close();
            process.waitFor();
        } catch (IOException e) {
            e.printStackTrace();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }
}

带参数的python文件执行

python 复制代码

public class ExecPythonFileWithArgs {
    public static void main(String[] args) {
        int a = 18, b = 19;
        args = new String[] { "python","D:\\PythonFileWithArgs.py",
        String.valueOf(a), String.valueOf(b) };
        try {
            Process process = Runtime.getRuntime().exec(args);
            BufferedReader in = new BufferedReader(new InputStreamReader(process.getInputStream()));
            String line = null;
            while ((line = in.readLine()) != null) {
                System.out.println(line);
            }
            in.close();
            process.waitFor();
        } catch (IOException e) {
            e.printStackTrace();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }
}

【Windows环境】使用bat脚本执行python文件【我猜想也是有Linux环境的执行方法的】

java 复制代码

public class ExecPythonBat {
    public static void main(String[] args) {
        try {
            Process process = Runtime.getRuntime().exec("cmd /c D:\\RunPythonFile.bat");
            BufferedReader in = new BufferedReader(new InputStreamReader(process.getInputStream()));
            String line = null;
            while ((line = in.readLine()) != null) {
                System.out.println(line);
            }
            in.close();
            process.waitFor();
        } catch (IOException e) {
            e.printStackTrace();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }
}

3.3类型三【读取python文件内的函数进行执行】

java 复制代码

public class ExecPythonFileCode {
    public static void main(String[] args) {
        PythonInterpreter interpreter = new PythonInterpreter();
        interpreter.execfile("D:\\PythonFile.py");
        PyFunction function = interpreter.get("add", PyFunction.class);
        int a = 3, b = 12;
        PyObject pyObject = function.__call__(new PyInteger(a), new PyInteger(b));
        System.out.println("The result is : " + pyObject);
        interpreter.close();
    }
}

4.python文件和执行脚本

文件一：PythonFile.py

python 复制代码

import numpy as np
a = np.arange(12).reshape(3,4)
print(a)
def add(a,b):
    return a+b;

文件二：PythonFileWithArgs.py

python 复制代码

import sys
 
def func(a,b):
    return (a+b)
 
if __name__ == '__main__':
    a = []
    for i in range(1, len(sys.argv)):
        a.append((int(sys.argv[i])))
    print(func(a[0],a[1]))

文件三：RunPythonFile.bat

powershell 复制代码

@echo off
cmd /k python E:\Anaconda3_Python\PythonFile.py