Java Common String Operations Summary

1. String to ASCII code

    public static string Stringtoascii (string value) {        StringBuffer SBU = new StringBuffer ();        char[] chars = Value.tochararray ();        for (int i = 0; i < chars.length; i++) {            if (I <= chars.length-1) {                int II = chars[i];                Sbu.append (integer.tohexstring (ii));            } else {                sbu.append ((int) chars[i]);            }        }        return sbu.tostring ();    }

2. ASCII transcoding string

    public static string Asciitostring (string value) {        if ("". Equals (value) | | Value = = null) {            return "";        }        StringBuffer sbuffer = new StringBuffer ();        char[] chars = Value.tochararray ();        for (int i = 0; i < chars.length; i = i + 2) {            if (I < chars.length-1) {                int II = integer.valueof (                    Ch Aracter.tostring (Chars[i]) + character.tostring (chars[i + 1]);                Sbuffer.append ((char) (ii));            }        }        return sbuffer.tostring ();    }

3. Input Flow byte array

    public static String Inputstream2byte (InputStream inputstream) throws IOException {        Bytearrayoutputstream bos = new B Ytearrayoutputstream ();        byte[] buffer = new byte[1024];        int len =-1;        while (len = inputstream.read (buffer))! =-1) {            bos.write (buffer, 0, Len);        }        Bos.close ();        return new String (Bos.tobytearray (), "UTF-8");    }

4. Enter the flow string

    public static String inputstreamtostring (InputStream in) throws Exception {                Bytearrayoutputstream outstream = new by Tearrayoutputstream ();        byte[] data = new byte[1024];        int count =-1;        while ((count = in.read (data, 0, 2048))! =-1)            outstream.write (data, 0, count);                data = null;        return new String (Outstream.tobytearray ());    }

　

5. Determine if the input contains Chinese

    public static Boolean Ischinese (char c) {        Character.unicodeblock UB = Character.UnicodeBlock.of (c);        if (UB = = Character.UnicodeBlock.CJK_UNIFIED_IDEOGRAPHS | | ub = = Character.UnicodeBlock.CJK_COMPATIBILITY_IDEOGRAPHS                | | ub = = Character.UnicodeBlock.CJK_UNIFIED_IDEOGRAPHS_EXTENSION_A | | ub = = Character.UnicodeBlock.CJK_UNIFIED_ Ideographs_extension_b                | | ub = = Character.UnicodeBlock.CJK_SYMBOLS_AND_PUNCTUATION | | ub = = Character.UnicodeBlock.HALFWIDTH_AND_FULLWIDTH_FORMS                | | ub = = Character.UnicodeBlock.GENERAL_PUNCTUATION) {            return true;        }        return false;    }     public static Boolean Ischinese (String strName) {        char[] ch = strname.tochararray ();        for (int i = 0; i < ch.length; i++) {            char c = ch[i];            if (Ischinese (c)) {                return true;            }        }        return false;    }

　　

6. Verify the legitimacy of the subnet mask: After the subnet mask is converted to binary, it cannot be all 1, nor all 0, must be contiguous 1 or successive 0, that is, 1 and 0 cannot alternate.

Implementation method, the first 4 integer number of fields in accordance with each eight-bit splicing, soft after conversion to binary display, using regular expressions to match.

    public static Boolean Checkmask (String maskstr) {        string[] ips = maskstr.split ("\ \.");          String binaryval = "";          for (int i = 0; i < ips.length; i++)          {              String binarystr = integer.tobinarystring (Integer.parseint (ips[i])); 
   integer times = 8-binarystr.length ();                            for (int j = 0; J < times; J + +)              {                  binarystr = "0" +  binarystr;  Eight-bit, eight-bit merge required each time            }              binaryval + = binarystr;          }          Pattern Regxpattern = Pattern.compile ("^[1]*[0]*$");        if (Regxpattern.matcher (Binaryval). Matches ())          {              return true;          } else {            return false;        }    }

7. Check the legality of the IP and convert to an integer representation

    public static Boolean Validip (String IP) {if (IP = = null) {return false; } String Ip_regex = "\\b (?!                                                       \\d\\d\\d) \\d+|1\\d\\d|2[0-4]\\d|25[0-5] \ \. " + "((?!                                                       \\d\\d\\d) \\d+|1\\d\\d|2[0-4]\\d|25[0-5] \ \. " + "((?!                                                       \\d\\d\\d) \\d+|1\\d\\d|2[0-4]\\d|25[0-5] \ \. " + "((?!        \\d\\d\\d) (\\d+|1\\d\\d|2[0-4]\\d|25[0-5]) \\b ";        Pattern Ippattern = Pattern.compile (Ip_regex);        Matcher Matcher = Ippattern.matcher (IP);    return matcher.matches ();        public static Integer Ipstring2int (String strIp) {if (!validip (strIp)) return null;        int[] IP = new INT[4];        string[] ips = strip.split ("\ \");        Ip[0] = Integer.parseint (ips[0]);        IP[1] = Integer.parseint (ips[1]);        IP[2] = Integer.parseint (ips[2]);        IP[3] = Integer.parseint (ips[3]); ReturN (ip[0] <<) + (Ip[1] << +) + (Ip[2] << 8) + ip[3]; }

　　

　　

　　

Java Common String Operations Summary