如何用Java向进程发送EOF

Question

我想在Java程序中运行groff。输入来自字符串。在实际的命令行中，我们将终止Linux/Mac中^D的输入。那么如何在Java程序中发送这个终止符呢？

String usage +=
    ".Dd \[year]n"+
    ".Dt test 1n"+
    ".Osn"+
    ".Sh testn"+
    "^Dn";    // <--- EOF here?
Process groff = Runtime.getRuntime().exec("groff -mandoc -T ascii -");
groff.getOutputStream().write(usage.getBytes());
byte[] buffer = new byte[1024];
groff.getInputStream().read(buffer);
String s = new String(buffer);
System.out.println(s);

或者其他想法？

Answer 1

^D不是字符；这是一个由shell解释的命令，告诉它关闭进程的流（因此进程在stdin上接收EOF）。

您需要在代码中执行同样的操作；冲洗并关闭OutputStream:

String usage =
  ".Dd \[year]n" +
  ".Dt test 1n" +
  ".Osn" +
  ".Sh testn";
...
OutputStream out = groff.getOutputStream();
out.write(usage.getBytes());
out.close();
...

Answer 2

我写了这个实用程序方法：

public static String pipe(String str, String command2) throws IOException, InterruptedException {
    Process p2 = Runtime.getRuntime().exec(command2);
    OutputStream out = p2.getOutputStream();
    out.write(str.getBytes());
    out.close();
    p2.waitFor();
    BufferedReader reader
            = new BufferedReader(new InputStreamReader(p2.getInputStream()));
    StringBuilder sb = new StringBuilder();
    String line;
    while ((line = reader.readLine()) != null) {
        sb.append(line + "n");
    }
    return sb.toString();
}