Python在Java中的调用技巧-乐工具技术知识

Python在Java中的调用并不是直接运行Python代码，而是通过Java程序调用Python解释器来执行Python脚本。以下是一些在Java中调用Python的技巧：

使用ProcessBuilder类：Java的ProcessBuilder类可以启动一个新的进程并连接到它的输入/输出/错误管道。你可以使用它来运行Python解释器并执行Python脚本。例如：

try {
    ProcessBuilder pb = new ProcessBuilder("python", "myscript.py");
    Process process = pb.start();
    // 可以使用process.getInputStream()、process.getOutputStream()和process.getErrorStream()来读取和写入进程的输入/输出/错误流
    int exitCode = process.waitFor();
    System.out.println("Exit code: " + exitCode);
} catch (IOException | InterruptedException e) {
    e.printStackTrace();
}

传递参数给Python脚本：你可以通过ProcessBuilder类的命令行参数列表将参数传递给Python脚本。例如：

ProcessBuilder pb = new ProcessBuilder("python", "myscript.py", "arg1", "arg2");

处理Python脚本的输出：你可以使用Thread来读取Python脚本的输出，以避免阻塞Java线程。例如：

try {
    ProcessBuilder pb = new ProcessBuilder("python", "myscript.py");
    Process process = pb.start();
    Thread outputThread = new Thread(() -> {
        try (BufferedReader reader = new BufferedReader(new InputStreamReader(process.getInputStream()))) {
            String line;
            while ((line = reader.readLine()) != null) {
                System.out.println(line);
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    });
    outputThread.start();
    int exitCode = process.waitFor();
    outputThread.join();
    System.out.println("Exit code: " + exitCode);
} catch (IOException | InterruptedException e) {
    e.printStackTrace();
}

处理Python异常：如果Python脚本在执行过程中抛出异常，Java进程不会捕获这些异常。你可以通过读取错误流来获取Python脚本的错误信息。例如：

try {
    ProcessBuilder pb = new ProcessBuilder("python", "myscript.py");
    Process process = pb.start();
    Thread errorThread = new Thread(() -> {
        try (BufferedReader reader = new BufferedReader(new InputStreamReader(process.getErrorStream()))) {
            String line;
            while ((line = reader.readLine()) != null) {
                System.err.println(line);
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    });
    errorThread.start();
    int exitCode = process.waitFor();
    errorThread.join();
    System.out.println("Exit code: " + exitCode);
} catch (IOException | InterruptedException e) {
    e.printStackTrace();
}