为什么PrintWriter可以用于输出到Process，而BufferedWriter不起作用？

Question

I have code similar to the following that interacts with gdb from Java. I start the process with gdb and then get the process's streams. I have a thread that constantly reads the output of the process (using procOut ) and prints it to the screen, and I send commands to gdb using procIn.println("some_command") -

Process proc = new ProcessBuilder("gdb").start;

procOut = new BufferedReader(new InputStreamReader(proc.getInputStream()));
procErr = new BufferedReader(new InputStreamReader(proc.getErrorStream()));
procIn = new PrintWriter(new BufferedWriter(new OutputStreamWriter(proc.getOutputStream())));

However if I change procIn to a BufferedWriter -

procIn = BufferedWriter(new OutputStreamWriter(proc.getOutputStream()));

and use procIn.write("some_command") , it doesn't work and gdb doesnt get the input. Anyone know why this happens?

Answer 1

您必须在BufferedWriter上执行flush（）以确保其消失。