如何读取下面XML格式节点的数据
<?xml version = "1.0" encoding = "gb2312"?>
<bocb2e version="100" security="true" lang="chs">
<head>
<termid>E127000000001</termid>
<trnid>20060704001</trnid>
<custid>12345678</custid>
<cusopr>BOC</cusopr>
<trncod>b2e0005</trncod>
<token>9TTQALYGH1</token>
</head>
<trans>
<trn-b2e0005-rs>
<status>
<rspcod>B001</rspcod>
<errmsg>OK</errmsg>
</status>
<b2e0005-rs>
<status>
<rspcod>B001</rspcod>
<errmsg>OK</errmsg>
</status>
<account>
<ibknum>40001</ibknum>
<actacn>800100053108091001</actacn>
<acntname>账户名称</acntname>
</account>
<balance>
<bokbal>99999.99</bokbal>
<avabal>99999.99</avabal>
</balance>
<baldat>20060704</baldat>
</b2e0005-rs>
</trn-b2e0005-rs>
</trans>
</bocb2e>
如何读取 bokbal 这个节点的数据?