process进程堵塞问题

[aotian16]

/**
 * 
 */
package pkg;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

/**
 * @author 2172980000502
 *
 */
public class TestProcess {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		try {
			Process exec = Runtime.getRuntime().exec("cmd");
			
			InputStream inputStream = exec.getInputStream();
			OutputStream outputStream = exec.getOutputStream();
			
			outputStream.write("dir\r\n".getBytes());
			
			int c;
			while ((c = inputStream.read())!=-1) {
				System.out.print((char)c);
			}
			
			System.out.println("end");
		} catch (IOException e) {
			e.printStackTrace();
		}

	}

}

程序会堵塞在while 那里是什么问题呢?
还有dir命令貌似也没有执行?

[sffx123]

1.命令是cmd应该不行这个会导致命令等待，所以不返回-1，你可以换成ping测试一下 2.一次应该只能一个命令，dir没被执行

 try {
	            Process proc = Runtime.getRuntime().exec("ping www.baidu.com");
	            InputStream inputStream = proc.getInputStream();
	            String line  = "";
	    		BufferedReader buf = null; 
	            buf = new BufferedReader(new InputStreamReader(inputStream));
				while ((line = buf.readLine()) != null){
					System.out.println(line);
				}
	            System.out.println("end");
	        } catch (IOException e) {
	            e.printStackTrace();
	       }

[aotian16]

没有人知道吗, 求指点啊