Hi Maheswarareddy Konda!
You can try something like this:
<?xml version='1.0'?>
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:template match="/">
<Root>
<xsl:apply-templates select="//String"/>
</Root>
</xsl:template>
<xsl:template match="String">
<xsl:call-template name="Split">
<xsl:with-param name="srcStr" select="''"/>
<xsl:with-param name="sep" select="''"/>
<xsl:with-param name="restStr" select="text()"/>
</xsl:call-template>
</xsl:template>
<xsl:template name="Split">
<xsl:param name="srcStr"/>
<xsl:param name="sep"/>
<xsl:param name="restStr"/>
<xsl:if test="string-length($restStr)">
<xsl:variable name="token">
<xsl:choose>
<xsl:when test="contains($restStr, '.')">
<xsl:value-of select="substring-before($restStr, '.')" />
</xsl:when>
<xsl:otherwise>
<xsl:value-of select="$restStr" />
</xsl:otherwise>
</xsl:choose>
</xsl:variable>
<xsl:variable name="currText" select="concat($srcStr, concat($sep, $token))" />
<item>
<text> <xsl:value-of select="$currText"/> </text>
</item>
<xsl:call-template name="Split">
<xsl:with-param name="srcStr" select="$currText" />
<xsl:with-param name="sep" select="'.'" />
<xsl:with-param name="restStr" select="substring-after($restStr, '.')" />
</xsl:call-template>
</xsl:if>
</xsl:template>
</xsl:stylesheet>
For source XML:
<?xml version="1.0" encoding="UTF-8"?>
<ns0:MyMessage xmlns:ns0="urn://test">
<String>111.222.333.444.555</String>
</ns0:MyMessage>
Result is:
<?xml version='1.0' ?>
<Root>
<item><text>111</text></item>
<item><text>111.222</text></item>
<item><text>111.222.333</text></item>
<item><text>111.222.333.444</text></item>
<item><text>111.222.333.444.555</text></item>
</Root>
Probably It's not optimized as I wrote this transformation very quickly. You can modify it accordingly. The main idea is to use recursive template call.
Regards.