Java调用python脚本，脚本日志如何输入到日志文件中？如何实时获取脚本日志？

Question

Java调用python脚本遇到的两个问题，求教：

• 1、Java调用python脚本,python脚本不会输出日志到日志文件；
  但是单独运行python脚本会输出日志文件，为什么？怎么解决？

• 2、Java调用python脚本，只会在脚本执行结束后才可以一次性获取脚本日志信息，怎么实现实时获取脚本执行日志？

相关代码和脚本

终端直接执行，会生成日志文件

python /tmp/pytest.py >>/tmp/pylog.log 2>&1

Java调用，不会新建生成日志文件

···
Runtime.getRuntime().exec(“python /tmp/pytest.py >>/tmp/pylog.log 2>&1”)
···

python脚本

#!/usr/bin/python
# -*- coding: UTF-8 -*-

import logging
import time

logging.basicConfig(level=logging.DEBUG)

for num in range(0, 3):
    time.sleep(1)
    logging.info('logging 当前序号 :' + str(num) )
    print' print当前序号 :', num

Answer 1

Don’t use the redirection character in Runtime.exec(), instead use process.getInputStream() to get the log. For example:

    Process process = Runtime.getRuntime().exec("python /tmp/pytest.py");
    try (FileOutputStream out = new FileOutputStream("/tmp/pylog.log")) {
        Streams.copy(process.getInputStream(), out);
    }

Answer 2

1 Create sh file
cd /tmp && echo "/usr/bin/python /tmp/pytest.py >>/tmp/pylog.log 2>&1" >> pytest.sh
2 in java Execute the sh file
Execute Runtime.getRuntime().exec(“/usr/bin/sh /tmp/pytest.sh”)
3 in java.

PS: Remember to use absolute addresses for python and sh commands.
My terminals are /usr/bin/python and /usr/bin/sh. Remember to adjust the response of your own terminal.