java调用可执行程序的问题

Question

API中的Runtime类其中有个方法：
Process exec(String[] cmdarray, String[] envp, File dir) 
          在指定环境和工作目录的独立进程中执行指定的命令和变量。 这几个参数cmdarray，envp和dir是怎么取值的，我不是很懂，谁能给我举个例子啊

Answer 1

//给你个例子  
 public void CmdMasm(String filepath,String filename  )  {
       boolean flag=false;  //标志，当第一次记录已读到的":",变成true
       int count=0; //记录":"的个数
       String result=""; //保存编译后的结果
       try  {
         String  line;
       /*  String[] command = new String[5];
         command[0] = "cmd.exe";
         command[1] = "/c";
         command[2] = "cd \""+filepath+"\"";
         command[3] = "&";
         command[4] = "E:\\examSys\\examClient\\visualassembly\\masm\\masm.exe";
         Process  p  =  Runtime.getRuntime().exec(command,null,new File("E:")); */  //正确
        File path = new File(filepath);
        String cmd ="cmd.exe /c E:\\examSys\\examClient\\visualassembly\\masm\\masm.exe";
        Process p = Runtime.getRuntime().exec(cmd,null,path);  System.out.println("filepath="+filepath);         String str=filename+"\n";
         OutputStream out = p.getOutputStream();
         InputStream in = p.getInputStream();
         BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(out));
        // BufferedReader reader = new BufferedReader(new InputStreamReader(in));
         InputStreamReader reader = new InputStreamReader(in);
         char c[] = new char[1];         while( reader.read(c)!=-1 )
           {
             System.out.print(c);
             if(count==4){
              result=result + new String(c);
             }
             if(c[0]==':' && flag == true)
             { count=count+1;
               System.out.println("\n");
               writer.write("\n");
               writer.flush();
             }
             if(c[0]==':' && flag == false)
             { flag = true;
               count=count+1;
               System.out.println(str);
               writer.write(str);
               writer.flush();
             }           }
         flag= false;
         reader.close();
         writer.close();
         }catch (Exception  err)  {
          System.out.println("错误");
          err.printStackTrace();
         }
         String element="";  //记录每个元素
         Vector v = new Vector();
         StringTokenizer tokenizer = new StringTokenizer(result.trim(), "\n\r", false);
          while( tokenizer.hasMoreTokens() ){
            element=tokenizer.nextToken();
            if(element.trim()!="")
            {
               v.add(element);
              // System.out.println(element);
            }
          }
         System.out.println(v.elementAt(1).toString().trim());
         System.out.println(v.elementAt(2).toString().trim());
     }

Answer 2

Runtime run = Runtime.getRuntime();

Answer 3

Runtime run = Runtime.getRuntime();

Answer 4

package com.dos;public class DosTest{

public static void main(String [] args){
try{
Process process=Runtime.getRuntime().exec("p.exe");
process.waitFor();
System.out.println("DOS Sucess");
}catch(Exception e){
e.printStackTrace();
}

}} 
看看这个,就差不多了,