如何在 python 代码中获取 .jar 执行的输出?

问题描述

我正在编写 python 模块，该模块执行 SQL 到 DBMS 并检索数据.我正在尝试使用 jdbc jar 文件而不是本机 DB 驱动程序.我想知道如何在 python 中执行 jar 文件并从 jar 执行中获取输出.而且我想知道如何将 SQL 字符串传递给 jar 参数.这是简化的代码.非常感谢任何帮助.

I'm programming the python module that executes SQL to DBMS and retrieves data. I'm trying to use jdbc jar files instead of native DB drivers. I'm wondering how to executes jar file in python and get output from jar execution. And I'd like to know how to pass SQL string to jar argument. Here is the simplified code. Any help is greatly appreciated.

[java代码]

public class GetDBResults {
    public static void main(String[] args) {

        // return sql results
        for(int i=0; i<=100; i++){
            // Is this the proper way to generate the output?
            System.out.println(i+"/t"+i*100+1);
    }
  }
}

[python代码]

subprocess.call( [ 'java','-jar','./GET_DB_DATA.jar' )

# how to get results from jar execution?
# how to pass SQL string to jar execution?

推荐答案

可以通过管道读取输出:

You can read the output through pipe:

>>> from subprocess import Popen, PIPE, STDOUT
>>> p = Popen(['java', '-jar', './GET_DB_DATA.jar'], stdout=PIPE, stderr=STDOUT)
>>> for line in p.stdout:
    print line

关于将字符串传递给标准输入，可以这样实现:

As regards passing string to stdin, you can achieve it this way:

>>> p = Popen(['cat'], stdin=PIPE, stdout=PIPE, stderr=STDOUT)
>>> stdout, stderr = p.communicate(input='passed_string')
>>> print stdout
passed_string

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