java 流与byte 互相转换，并与base64编码转换

在java 文件操作过程中，经常会用到stream to byte 还有 byte to stream ,另外如果是用来原创传输文件，还必须将流转换成base64 编码，然后才好传输， 一旦受到这个base64的字符串，接收端，需要将这个还原成流，保存为文件。

下面就是几个主要方法：
1. streamtobyte:

public static byte[] steamToByte(InputStream input) throws IOException{     ByteArrayOutputStream baos = new ByteArrayOutputStream();     int len = 0;     byte[] b = new byte[1024];     while ((len = input.read(b, 0, b.length)) != -1) {                             baos.write(b, 0, len);     }     byte[] buffer =  baos.toByteArray();     return buffer; }

2.bytetostream:

public static final InputStream byteTostream(byte[] buf) {          return new ByteArrayInputStream(buf);      }

3.文件内容base64编码:

public static String getBase64Content(ContentTransfer content) throws IOException{              InputStream inputStream = content.accessContentStream();         byte[] output = steamToByte(inputStream);         BASE64Encoder encoder = new BASE64Encoder();         String outstr = encoder.encode(output);         System.out.println(outstr);         saveBase64strToFile(outstr);         return outstr;          }

4. 转换base64字符串为文件

public static void saveBase64strToFile(String base64str){         if (base64str == null){             return ;         }         BASE64Decoder decoder = new BASE64Decoder();         try         {                       byte[] b = decoder.decodeBuffer(base64str);             for(int i=0;i<b.length;++i) {="" if(b[i]<0){="" b[i]+="256;" }="" string="" imgfilepath=""c:/base.jpg";//新生成的图片" outputstream="" out="new" fileoutputstream(imgfilepath);="" out.write(b);="" out.flush();="" out.close();="" catch="" (exception="" e){="" e.printstacktrace();="" <="" pre="">             <p>From：<a href="/" target="_blank">一号门</a></p>                    <div class="pagelist"></div>         </b.length;++i)>