用java代码执行命令行并获取返回结果

public class CmdUtil {

    public static void main(String[] args) {
        System.out.println(CmdUtil.exec(new String[] { "java","-ver" }));
    }

    public static String exec(String[]para) {
        try {
            Process proc = Runtime.getRuntime().exec(para);
            //读取正确结果流
            BufferedReader in = new BufferedReader(new InputStreamReader(proc.getInputStream()));
            //获取错误流
            BufferedReader error = new BufferedReader(new InputStreamReader(proc.getErrorStream()));
            StringBuilder rs = new StringBuilder();
            String line;
            while ((line = in.readLine()) != null) {
                rs.append(line).append("\n");
            }
            in.close();
            while ((line = error.readLine()) != null) {
                rs.append(line).append("\n");
            }
            error.close();
            //等待调用命令行的的线程执行完成
            proc.waitFor();
            return rs.toString();
        } catch (Exception e){
            e.printStackTrace();
        }
        return "";
    }
}