String str="sdfasdfasdfa加减法爱的色放就阿克苏地方啊";
InputStream is=new ByteArrayInputStream(str.toString.getBytes());//仔细领悟这个用处
ByteArrayOutputStream baos=new ByteArrayOutStream();
baos.write('a');
baos.write(1123);
String str="sdfsfsfs";
baos.write(str.getBytes());
byte[] buf=baos.toByteArray(); //仔细领悟这个用处