Java regular expression used to filter html tags

Java code

The code is as follows:

Copy code

Import java. util. regex. Matcher; Import java. util. regex. Pattern; Public class HtmlRegexpUtil { Private final static String regxpForHtml = "<([^>] *)>"; // filter all tags whose names start with <and end with> Private final static String regxpForImgTag = "<] *) s"> s * imgs + ([^>] *) s *> "; // find the IMG tag Private final static String regxpForImaTagSrcAttrib = "src =" ([^ "] +)"; // locate the SRC attribute of the IMG tag Public HtmlRegexpUtil (){ // TODO Auto-generated constructor stub } Public String replaceTag (String input ){ If (! HasSpecialChars (input )){ Return input; } StringBuffer filtered = new StringBuffer (input. length ()); Char c; For (int I = 0; I <= input. length ()-1; I ++ ){ C = input. charAt (I ); Switch (c ){ Case '<': Filtered. append ("& lt ;"); Break; Case '> ': Filtered. append ("& gt ;"); Break; Case '"': Filtered. append ("& quot ;"); Break; Case '&': Filtered. append ("& amp ;"); Break; Default: Filtered. append (c ); } } Return (filtered. toString ()); } Public boolean hasSpecialChars (String input ){ Boolean flag = false; If (input! = Null) & (input. length ()> 0 )){ Char c; For (int I = 0; I <= input. length ()-1; I ++ ){ C = input. charAt (I ); Switch (c ){ Case '> ': Flag = true; Break; Case '<': Flag = true; Break; Case '"': Flag = true; Break; Case '&': Flag = true; Break; } } } Return flag; }