Java 中如何调用DOS命令打开文件

Question

String cmd = "tasklist "；
           Process child = Runtime.getRuntime().exec(cmd);
            InputStream child_in = child.getInputStream();            System.out.println (cmd);
            BufferedReader  in=new BufferedReader(new InputStreamReader(child_in));
            String szstr1="";
            int count=0;            while ((szstr1=in.readLine())!=null){
                System.out.println(szstr1);
                count++;
            }
            System.out.print("count: "+count);
            child_in.close();
            in.close() ;
            child.destroy() ;
        } catch (IOException e) {
            System.err.println(e);
        }