Java调用Python脚本并获取返回值

在Java程序中有时须要调用Python的程序，这时能够使用通常的PyFunction来调用python的函数并得到返回值，可是采用这种方法有可能出现一些莫名其妙的错误，好比ImportError。在这种状况下能够采用另外一种方法：使用Java的Runtime，像在命令行直接调用python脚本那样调用python程序。此时能够经过文件做为脚本参数来传递Python程序所须要的参数，并从脚本的输入输出流来获取原本该打印在控制台的结果。

先准备好一个python文件：

def get_path(filename): y_t = np.loadtxt(filename) peolpex = int(y_t[0][0]) peolpey = int(y_t[0][1]) firex = int(y_t[1][0]) firey = int(y_t[1][1]) answer = getQ(peolpex, peolpey, firex, firey) return answer if __name__ == "__main__": filename = sys.argv[1] # print(filename)

    # root = Tk()
    # canvas = Canvas(root, bg="white")
    # canvas.pack()
    # colors = ['red', 'orange', 'green', 'black','yellow','white','pink']
 result = get_path(filename) # with open(filename, 'w') as f:
    # f.write(result)
    print result

对应的Java程序以下：

String result = ""; try { Process process = Runtime.getRuntime().exec("python /home/jia/fireevacuation/my.py " + filename); // process.waitFor();
            InputStreamReader ir = new InputStreamReader(process.getInputStream()); LineNumberReader input = new LineNumberReader(ir); result = input.readLine(); input.close(); ir.close(); // process.waitFor();
        } catch (IOException e) { logger.error("调用python脚本并读取结果时出错：" + e.getMessage()); } return result;