java读取文件内容的三种方法代码片断分享(java文件操作)

try {
           // 方法一
           bufferedreader br = new bufferedreader(new filereader(new file(
                   "d:\\1.xls")));
           // stringbuilder bd = new stringbuilder();
           stringbuffer bd = new stringbuffer();
           while (true) {
               string str = br.readline();
               if (str == null) {
                   break;
               }
               system.out.println(str);
               bd.append(str);
           }
           br.close();
           // system.out.println(bd.tostring());
           // 方法二
           inputstream is = new fileinputstream(new file("d:\\1.xls"));
           byte b[] = new byte[integer.parseint(new file("d:\\1.xls").length()
                   + "")];
           is.read(b);
           system.out.write(b);
           system.out.println();
           is.close();
           // 方法三
           reader r = new filereader(new file("d:\\1.xls"));
           char c[] = new char[(int) new file("d:\\1.xls").length()];
           r.read(c);
           string str = new string(c);
           system.out.print(str);
           r.close();
       } catch (runtimeexception e) {
           // todo auto-generated catch block
           e.printstacktrace();
       } catch (filenotfoundexception e) {
           // todo auto-generated catch block
           e.printstacktrace();
       } catch (ioexception e) {
           // todo auto-generated catch block
           e.printstacktrace();
       }