How to find string inside particular string and insert
Question
I have a method that gets XML string and in theory should insert a comment before EVERY particular tag. I wonder how to make it work
public static String addCommentXML(String xmlString, String tagName, String comment)
{
StringBuilder sb = new StringBuilder(xmlString);
for(int i = 0; i < sb.toString().length(); i++)
{
if(sb.toString().toLowerCase().contains("<"+tagName+">"))
{
sb.insert(sb.toString().indexOf("<"+tagName+">", i) - 1, "<!--"+ comment+"-->"+"\n");
}
}
return sb.toString();
}
Output of addCommentXML("somereallylongxml", "second", "it's a comment") should be
<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<first>
<!--it's a comment-->
<second>some string</second>
<!--it's a comment-->
<second>some string</second>
<!--it's a comment-->
<second><![CDATA[need CDATA because of < and >]]></second>
<!--it's a comment-->
<second/>
</first>
But it apparently doesn't work, since i don't know how to iterate through the string correctly to add before EVERY tagName, not only first, so we get infinite loop. How can i do that?
2 answers
solution1
1 2017-06-18 10:43:22
It can be easily done with JSOUP library. It's a perfect tool to work with HTML/XML.
https://mvnrepository.com/artifact/org.jsoup/jsoup/1.10.3
In your case it will look like this:
public static void main(String[] args) {
String processedXml = addCommentXML(getDocument(), "second", "it's a comment");
System.out.println(processedXml);
}
private static String addCommentXML(String xmlString, String tagName, String comment) {
Document document = Jsoup.parse(xmlString);
document.getElementsByTag(tagName).before("<!--" + comment + "-->");
return document.toString();
}
private static String getDocument() {
return "<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"no\"?>\n" +
"<first>\n" +
"<second>some string</second>\n" +
"<second>some string</second>\n" +
"<second><![CDATA[need CDATA because of < and >]]></second>\n" +
"<second/>\n" +
"</first>";
}
Output :
<html> <head></head> <body> <first> <!--it's a comment--> <second> some string </second> <!--it's a comment--> <second> some string </second> <!--it's a comment--> <second> need CDATA because of < and > </second> <!--it's a comment--> <second /> </first> </body> </html>
solution2
0 ACCPTED 2017-06-18 10:46:58
The proposed soliution here is a very straightforward one: splitting the input by the tagname, then joining the pieces together and inserting the comment and tagname in between.
public static String addCommentXML(String xmlString, String tagName, String comment)
{
String[] parts = xmlString.split("\\Q<" + tagName + ">\\E");
String output = parts[0];
for (int i = 1 ; i < parts.length ; i++) {
output += comment + "<" + tagName + ">" + parts[i];
}
return output;
}
pro: no 3rd party lib required
con: this method does not really parse the xml, therefore, sometimes it can produce erronous results (like if the tag is found inside comment...)
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