java - 运行时问题

Question

如何在 Windows 上运行，文件 filename.txt 没有被创建。

Process p = Runtime.getRuntime().exec("cmd echo name > filename.txt");

显然预期的输出是一个“filename.txt”应该被创建(C:\Documents and Settings\username\filename.txt)，内容为“name”。

---

能够使用以下代码进行管理，即使文件“filename.txt”不是使用 processBuilder 创建的

       Runtime runtime = Runtime.getRuntime();
       Process process = runtime.exec("cmd /c cleartool lsview");
       // Directly to file

//Process p = Runtime.getRuntime().exec( 
//              new String[] { "cmd", "/c", "cleartool lsview > filename.txt" },null, new File("C:/Documents and Settings/username/")); 

       InputStream is = process.getInputStream();
       InputStreamReader isr = new InputStreamReader(is);
       BufferedReader br = new BufferedReader(isr);
       String line;

       System.out.printf("Output of running %s is:", 
           Arrays.toString(args));

       while ((line = br.readLine()) != null) {
         System.out.println(line);
       }

或者，使用 ProceessBuilder，

Process process = new ProcessBuilder( "cmd", "/c", "cleartool lsview" ).start();
InputStream is = process.getInputStream();
BufferedReader br = new BufferedReader(new InputStreamReader(is));

System.out.printf("Output of running %s is:", Arrays.toString(args));

String line;
while ((line = br.readLine()) != null) {
    System.out.println(line);
}

Answer 1

你实际上应该使用 ProcessBuilder而不是 Runtime.exec(参见 the docs)。

ProcessBuilder pb = new ProcessBuilder("your_command", "arg1", "arg2");
pb.directory(new File("C:/Documents and Settings/username/"));

OutputStream out = new FileOutputStream("filename.txt");
InputStream in = pb.start().getInputStream();

byte[] buf = new byte[1024];
int len;
while ((len = in.read(buf)) > 0)
    out.write(buf, 0, len);

out.close();

(如果我有一台 windows 机器，我会使其适应 cmd 和 echo ......随时编辑这篇文章!)