PY4J 回调服务器错误答案

【问题标题】：PY4J callback server errorPY4J 回调服务器错误
【发布时间】：2014-09-28 11:01:47
【问题描述】：

我正在尝试在 PY4J 网站上运行回调服务器的示例 here

但我遇到了以下异常： "py4j.protocol.Py4JNetworkError: 尝试启动回调服务器时出错"

这是代码：

Java：

package py4j.examples;

import java.util.ArrayList;
import java.util.List;
import java.util.Random;

import py4j.GatewayServer;

public class OperatorExample {

    // To prevent integer overflow
    private final static int MAX = 1000;

    public List<Integer> randomBinaryOperator(Operator op) {
            Random random = new Random();
            List<Integer> numbers = new ArrayList<Integer>();
            numbers.add(random.nextInt(MAX));
            numbers.add(random.nextInt(MAX));
            numbers.add(op.doOperation(numbers.get(0), numbers.get(1)));
            return numbers;
    }

    public List<Integer> randomTernaryOperator(Operator op) {
            Random random = new Random();
            List<Integer> numbers = new ArrayList<Integer>();
            numbers.add(random.nextInt(MAX));
            numbers.add(random.nextInt(MAX));
            numbers.add(random.nextInt(MAX));
            numbers.add(op.doOperation(numbers.get(0), numbers.get(1), numbers.get(2)));
            return numbers;
    }

    public static void main(String[] args) {
            GatewayServer server = new GatewayServer(new OperatorExample());
            server.start();
    }

}

界面：

package py4j.examples;

public interface Operator {

    public int doOperation(int i, int j);

    public int doOperation(int i, int j, int k);

}

Python：

from py4j.java_gateway import JavaGateway

class Addition(object):
    def doOperation(self, i, j, k = None):
        if k == None:
             return i + j
        else:
             return i + j + k

    class Java:
        implements = ['py4j.examples.Operator']

if __name__ == '__main__':
    gateway = JavaGateway(start_callback_server=True)
    operator = Addition()
    numbers = gateway.entry_point.randomBinaryOperator(operator)
    print(numbers)
    numbers = gateway.entry_point.randomTernaryOperator(operator)
    print(numbers)
    gateway.shutdown()

正如我提到的，我遇到了这个异常

py4j.protocol.Py4JNetworkError：尝试启动回调服务器时出错。

这是堆栈跟踪：

Traceback (most recent call last):
  File "/home/amir/Python code/callback_example.py", line 14, in <module>
    gateway = JavaGateway(start_callback_server=True)
  File "/usr/local/lib/python2.7/dist-packages/py4j-0.8.2.1-py2.7.egg/py4j/java_gateway.py", line 851, in __init__
    self._start_callback_server(python_proxy_port)
  File "/usr/local/lib/python2.7/dist-packages/py4j-0.8.2.1-py2.7.egg/py4j/java_gateway.py", line 867, in _start_callback_server
    self._callback_server.start()
  File "/usr/local/lib/python2.7/dist-packages/py4j-0.8.2.1-py2.7.egg/py4j/java_gateway.py", line 1091, in start
    raise Py4JNetworkError(msg)
py4j.protocol.Py4JNetworkError: An error occurred while trying to start the callback server
[Finished in 0.5s with exit code 1]

【问题讨论】：

你能包含完整的堆栈跟踪吗？
嗨，我在帖子中添加了堆栈跟踪。谢谢。

标签： java python py4j

【解决方案1】：

我发现了问题所在。

当我使用 Sublime Text 运行 Python 脚本并且构建完成时，使用端口（在本例中为 25334）的进程仍在运行，因此当我再次尝试运行脚本时端口正在使用中.

还是谢谢。

【讨论】：