changing xml values takes as a string in java

String
-------------------
<DslOrder index="1422796670990">
<orderId index="1422796671001">123456</orderId>
<AsdlServiceDetails index="1422796670991">
<bandwidth index="1422796670993">45678</bandwidth>
</AsdlServiceDetails>
<SubscriberInfo index="1422796670994">
<Address index="1422796670996">

<City index="1422796670999">MO</City>

<PostalCode index="1422796670998">456</PostalCode>

<Street index="1422796670997">sdfghh</Street>

</Address>

<PhoneNumber index="1422796671000">45678</PhoneNumber>

<Name index="1422796670995">sedrtfgh</Name>

</SubscriberInfo>

</DslOrder>

I have thisString With me. I need to change the value of the String in between Xml Elements. How do I Achieve this Dynamically.

Thanks in advance