请看下面这个例子

public static String escapeHTMLTags( String input ) {

// Check if the string is null or zero length -- if so, return what was sent in.

if( input == null || input.length() == 0 ) {

return input;

}

// Use a StringBuffer in lieu of String concatenation -- it is much more efficient this way.

StringBuffer buf = new StringBuffer();

char ch = ' ';

for( int i=0; i

ch = input.charAt(i);

if( ch == '<' ) {

buf.append( "<" );

}

else if( ch == '>' ) {

buf.append( ">" );

}

else {

buf.append( ch );

}

}

return buf.toString();

}