Java调用Python脚本：深入解析9009错误及跨语言交互实践

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

public class PythonScriptRunner {

    public boolean isUsbConnected() {
        Process process = null;
        BufferedReader reader = null;
        BufferedReader errorReader = null; // 用于捕获错误流
        try {
            // 推荐使用Python解释器的绝对路径，避免PATH问题
            // 根据您的Python安装路径进行修改
            String pythonInterpreterPath = "C:\Python\Python311\python.exe"; // 示例路径，请替换为您的实际路径
            String scriptPath = "C:\CS IA\src\java\findUSB.py"; // Python脚本的绝对路径

            // 构建进程命令：[Python解释器路径, Python脚本路径]
            ProcessBuilder processBuilder = new ProcessBuilder(pythonInterpreterPath, scriptPath);
            // 启动进程
            process = processBuilder.start();

            // 读取Python脚本的标准输出
            reader = new BufferedReader(new InputStreamReader(process.getInputStream()));
            String line;
            boolean isConnected = false;

            // 假设Python脚本最后一行输出的是布尔值
            while ((line = reader.readLine()) != null) {
                System.out.println("Python stdout: " + line); // 打印Python脚本的输出，方便调试
                // 尝试解析最后一行输出的布尔值
                if (line.trim().equalsIgnoreCase("True")) {
                    isConnected = true;
                } else if (line.trim().equalsIgnoreCase("False")) {
                    isConnected = false;
                }
                // 注意：如果Python脚本有其他输出，需要更精确的解析逻辑
            }

            // 读取Python脚本的标准错误流
            errorReader = new BufferedReader(new InputStreamReader(process.getErrorStream()));
            StringBuilder errorOutput = new StringBuilder();
            while ((line = errorReader.readLine()) != null) {
                errorOutput.append(line).append("
");
            }
            if (errorOutput.length() > 0) {
                System.err.println("Python stderr:
" + errorOutput.toString());
            }

            // 等待Python进程结束并获取退出码
            int exitCode = process.waitFor();
            System.out.println("Python script exited with code: " + exitCode);

            // 根据退出码和解析结果判断
            if (exitCode == 0) { // 退出码为0通常表示成功
                if (isConnected) {
                    System.out.println("The device is connected.");
                    return true;
                } else {
                    System.out.println("The device is not connected.");
                    return false;
                }
            } else {
                System.err.println("Python script execution failed with non-zero exit code: " + exitCode);
                return false;
            }

        } catch (IOException | InterruptedException e) {
            System.err.println("Error executing Python script: " + e.getMessage());
            e.printStackTrace();
            return false;
        } finally {
            // 关闭流和销毁进程
            try {
                if (reader != null) reader.close();
                if (errorReader != null) errorReader.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
            if (process != null) {
                process.destroy(); // 确保进程被销毁
            }
        }
    }

    public static void main(String[] args) {
        PythonScriptRunner runner = new PythonScriptRunner();
        boolean connected = runner.isUsbConnected();
        System.out.println("Final result: USB Connected = " + connected);
    }
}

import usbmonitor
from usbmonitor.attributes import ID_MODEL, ID_MODEL_ID, ID_VENDOR_ID
import sys # 导入sys模块

lookFor = "USB\VID_058F&PID_9540\5&54725E2&0&2"

def is_connected(device_id_to_find):
    """
    检查指定USB设备是否连接。
    """
    try:
        monitor = usbmonitor.USBMonitor()
        devices_dict = monitor.get_available_devices()

        for device_id, device_info in devices_dict.items():
            # 简化比较，只比较VID和PID部分
            # 示例：USBVID_058F&PID_9540&54725E2&0&2
            # 比较 'VID_058F&PID_9540' 部分
            current_device_vid_pid = device_id.split('\')[1] if '\' in device_id else ''
            target_device_vid_pid = device_id_to_find.split('\')[1] if '\' in device_id_to_find else ''

            if current_device_vid_pid == target_device_vid_pid:
                return True
        return False
    except Exception as e:
        # 打印错误到标准错误流，Java端可以捕获
        print(f"Error in Python script: {e}", file=sys.stderr)
        return False # 发生错误时返回False

if __name__ == "__main__":
    # 仅输出最终的布尔结果，方便Java解析
    result = is_connected(lookFor)
    print(str(result)) # 确保输出的是"True"或"False"字符串
    # 注意：原脚本中的 "Found" / "Not Found" 和 "hello world" 不应出现在最终用于Java解析的输出中
    # 如果需要调试信息，可以打印到sys.stderr
    print("hello world from python file at: src/java/findUSB.py", file=sys.stderr) # 调试信息输出到错误流