写入Java进程的InputStream
写入Java进程的InputStream
提问于 2013-09-20 03:41:52
我有一段启动java进程(即:执行编译后的java代码)的代码，通过
ProcessBuilder builder = new ProcessBuilder("java", "Sample", "arg1", "arg2");
builder.redirectErrorStream(true);
Process process = builder.start();通过这个，我基本上可以处理输出和错误
OutputStream stdin = process.getOutputStream(); // <- Eh?
InputStream stdout = process.getInputStream();
BufferedReader reader = new BufferedReader(new InputStreamReader(stdout));
BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(stdin));
// reader.readLine() blah blah现在，我如何将输入发送到stdin？也就是说，如果进程执行的代码有一行等待输入，如下所示：
Scanner scan = new Scanner(System.in);
String val = scan.nextLine();
System.out.println(val);我试过这个：
writer.write("I'm from the stdin!.");
writer.flush();虽然什么都没发生。控制台仍在等待输入。
有什么想法吗？
编辑：问题已回答，如下所示。我正在编辑以显示错误代码(我没有包含btw。哈哈)。
在writer.write()部分之前，我有一个
String line;
line = reader.readLine();
while (line != null) {
System.out.println(line);
line = reader.readLine();
}回答 3
Stack Overflow用户
回答已采纳
发布于 2013-09-20 03:44:18
从流程的角度来看，Process OutputStream (我们的观点)就是标准输入
OutputStream stdin = process.getOutputStream(); // write to this所以你所拥有的应该是正确的。
我的驱动程序(对try- with -resources语句应用您自己的最佳实践)
public class ProcessWriter {
public static void main(String[] args) throws Exception {
ProcessBuilder builder = new ProcessBuilder("java", "Test");
builder.directory(new File("C:\\Users\\sotirios.delimanolis\\Downloads"));
Process process = builder.start();
OutputStream stdin = process.getOutputStream(); // <- Eh?
InputStream stdout = process.getInputStream();
BufferedReader reader = new BufferedReader(new InputStreamReader(stdout));
BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(stdin));
writer.write("Sup buddy");
writer.flush();
writer.close();
Scanner scanner = new Scanner(stdout);
while (scanner.hasNextLine()) {
System.out.println(scanner.nextLine());
}
}
}我的应用程序
public class Test {
public static void main(String[] args) throws Exception {
Scanner console = new Scanner(System.in);
System.out.println("heello World");
while(console.hasNextLine()) {
System.out.println(console.nextLine());
}
}
}运行驱动程序打印
heello World
Sup buddy出于某种原因，我需要close()。仅靠flush()是无法做到这一点的。
编辑如果您提供的不是close()，而是\n，它也可以工作。
所以有了
writer.write("Sup buddy");
writer.write("\n");
writer.write("this is more\n");
writer.flush(); 驱动程序打印
heello World
Sup buddy
this is moreStack Overflow用户
发布于 2021-11-29 14:07:30
这是一个例子，也许可以帮助某些人
import java.io.IOException;
import java.io.File;
import java.io.OutputStream;
import java.io.InputStream;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.util.Scanner;
public class Main {
public static void main(String[] args) throws IOException {
String[] commands = {"C:/windows/system32/cmd.exe"};
ProcessBuilder builder = new ProcessBuilder(commands);
builder.directory(new File("C:/windows/system32"));
Process process = builder.start();
OutputStream stdin = process.getOutputStream();
InputStream stdout = process.getInputStream();
InputStream stderr = process.getErrorStream();
BufferedReader reader = new BufferedReader(new InputStreamReader(stdout));
BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(stdin));
BufferedReader error = new BufferedReader(new InputStreamReader(stderr));
new Thread(() -> {
String read;
try {
while ((read = reader.readLine()) != null) {
System.out.println(read);
}
} catch (IOException e) {
e.printStackTrace();
}
}).start();
new Thread(() -> {
String read;
try {
while ((read = error.readLine()) != null) {
System.out.println(read);
}
} catch (IOException e) {
e.printStackTrace();
}
}).start();
new Thread(() -> {
while (true) {
try {
Scanner scanner = new Scanner(System.in);
writer.write(scanner.nextLine());
writer.newLine();
writer.flush();
} catch (IOException e) {
e.printStackTrace();
}
}
}).start();
}
}Stack Overflow用户
发布于 2019-08-21 19:09:07
您需要添加结束行字符("\n")。
像这样：
writer.write("I'm from the stdin!.\n");
writer.flush();页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/18903549
复制相关文章
相似问题
腾讯云开发者
