在Java执行Python脚本3种方法

three-ways-to-run-python-script-in-java

本文介绍在Java执行Python脚本3种方法，使用Java实现的Python解析器Jython，使用Runtime运行Shell命令，使用ProcessBuilder创建操作系统进程。

1. 使用Jython

Jython是一个Java实现的Python解释器。org.python.util.PythonInterpreter类是Jython解释器的标准封装。

The PythonInterpreter class is a standard wrapper for a Jython interpreter for embedding in a Java application.

一个简单实例

HelloWorld.java如下：

import java.io.*;
import org.python.core.PyInstance;  
import org.python.util.PythonInterpreter;  

public class HelloWorld {  
    public static void main(String[] args) {  
        System.out.println("Hello Java World!");  

        PythonInterpreter interpreter = new PythonInterpreter();  
        InputStream pyfile = new FileInputStream("Hello.py"); 
        interpreter.execfile(pyfile);  ///执行python py文件
        filepy.close();
    }  
}

Hello.py如下：

#!/usr/bin/env python

print("Hello Python!")

Hello.sh如下：

javac HelloWorld.java
java HelloWorld

2. 使用Runtime

使用java.lang.Runtime.exec，执行Shell的命令。

public Process exec(String command) throws IOException
public Process exec(String command, String[] envp) throws IOException
public Process exec(String command, String[] envp, File dir) throws IOException

一个简单实例

import java.io.*;

public class HelloWorld_Runtime {  
    public static void main(String[] args) {  
        System.out.println("Hello Java World!");  

        // get the current runtime assosiated with this process
        Runtime run = Runtime.getRuntime();

        // Executes the specified string command in a separate process with the specified environment and working directory.
        Process process = run.exec("python Hello.py");
    }  
}

执行上述代码，提示错误：

HelloWorld_Runtime.java:12: error: unreported exception IOException; must be caught or declared to be thrown
        Process process = run.exec("python Hello.py");
                                  ^

3. 使用ProcessBuilder

使用ProcessBuilder创建操作系统进程。

public ProcessBuilder command(String... command)  // java.lang.ProcessBuilder.command()

Process p = new ProcessBuilder("myCommand", "myArg").start();

一个简单实例

import java.io.*;

public class HelloWorld_ProcessBuilder {  
    public static void main(String[] args) {  
        System.out.println("Hello Java World!");  

        // get the current runtime assosiated with this process
        Runtime run = Runtime.getRuntime();

        // Create operating system processes, set this process builder's operating system program and arguments, start a new process
        Process p = new ProcessBuilder().command("python Hello.py").start();
    }  
}

执行上述代码，提示错误：

HelloWorld_ProcessBuilder.java:12: error: unreported exception IOException; must be caught or declared to be thrown
        Process p = new ProcessBuilder().command("python Hello.py").start();
                                                                         ^