escaping - How to identify a special character in a file using java -

i have .doc file contains header before ÐÏ , need remove characters exist before ÐÏ.

example : asdfasdfasdfasfasdfasfÐÏ9asjdfkj

i have used below code.

inputstream = new   fileinputstream("d:\\users\\vinoth\\workspace\\testing\\testing_2.doc");     datainputstream dis = new datainputstream(is);     outputstream os = new  fileoutputstream("d:\\users\\vinoth\\workspace\\testing\\testing_3.doc");     dataoutputstream dos = new dataoutputstream(os);     byte[] buff = new byte[dis.available()];     dis.readfully(buff);     char temp = 0;     boolean start = false;     try{     for(byte b:buff){         char c = (char)b;         if(temp == 'Ð' && c == 'Ï' ){             start = true;           }         if(start){             dos.write(c);         }         temp = c;      } 

however , not writing in file first if condition not getting satisfied. please advise how can perform .

there wrong when use char c = (char)b;

refer byte-and-char-conversion-in-java

you see

a character in java unicode code-unit treated unsigned number.

take case example. byte binary presentation of character 'Ï' 11001111. refer oracle tutorial,

byte: byte data type 8-bit signed two's complement integer. has minimum value of -128 , maximum value of 127 (inclusive).

so value of byte -49. however, unicode usage, 11001111 should interpreted unsigned byte , should 207 actually.

int = b & 0xff;  

will unsigned byte value of binary presentation.

you can modify code below. debug, have changed file path , file format. i'm not sure whether .doc issue code has bugs mentioned actually.

import java.io.*;  public class test {     public static void main(string args[]){         inputstream is;         try {             = new   fileinputstream("testing_2.txt");             datainputstream dis = new datainputstream(is);             outputstream os = new  fileoutputstream("testing_3.txt");             dataoutputstream dos = new dataoutputstream(os);             byte[] buff = new byte[dis.available()];             dis.readfully(buff);             char temp = 0;             boolean start = false;             for(byte b:buff){                 int = b & 0xff;                 char c = (char)i;                 if(temp == 'Ð' && c == 'Ï' ){                     start = true;                   }                 if(start){                     dos.write(c);                 }                 temp = c;              }           } catch (exception e) {             // todo auto-generated catch block             e.printstacktrace();          }     } }