java - 从 python 调用 Java 应用程序时无法读取文件

Question

我有一个 Java 程序，它读取一个文件(其中包含来自本地语言的字符)并填充一个字符串。当程序直接运行时，它工作正常。

但是当从 Python 调用相同的程序时，它无法填充字符串。

        public static void main(String[] args) {
        File inputFile = new File("input.txt");
        BufferedReader br = new BufferedReader(new InputStreamReader(new FileInputStream(inputFile),"UTF-8"));
      string output = "";
        while ((line = br.readLine()) != null) {
           // This block never hits when invoked by python. It works fine when java program runs directly.
           output +=line+" ";
         }
         ...
         }

我在 Python 中调用它如下

cmd = ['java', java_class]
subprocess.Popen(cmd, shell=True, stdin=subprocess.PIPE, stdout=subprocess.PIPE)

有什么意见吗？顺便说一句，我使用的是 Atom IDE，不确定这是否有任何区别。

Answer 1

我试过你的例子，它对我有用。让我们看看它是否适合你。然后我会回复你我对这个问题的看法。

import java.io.*;


public class Python2JavaMessaging {
        public static void main(String[] args) {
                try {
                        BufferedReader bufferRead = new BufferedReader(new InputStreamReader(System.in));
                        PrintWriter writer = new PrintWriter("result.txt", "UTF-8");
                        String s = bufferRead.readLine();
                        while(s.equals("x")==false) {
                                writer.println(s);
                                s = bufferRead.readLine();
                        }
                        writer.close();
                } catch(IOException e) {
                        e.printStackTrace();
                }
        }
}

Python脚本如下:

#!/usr/bin/python

import subprocess

cmd = ['java', '-classpath', '.' , 'Python2JavaMessaging']
p = subprocess.Popen(cmd, stdin=subprocess.PIPE, stdout=subprocess.PIPE, encoding='utf8')

p.stdin.write("First line\r\n")
p.stdin.write("Second line\r\n")
p.stdin.write("x\r\n") # this line will not be printed into the file