我这个XML中的节点该如何读取?
<master cd_count="1" cd_release_date="2000/01/08" media_id="671902" volume="1" title="Tseng Shu Ching Ching Hsuan Chi" ll_title="精選">
<product_code type="UPC">0724352848454</product_code>
<alternate_product_code type="Digital_ICPN">0724352848454</alternate_product_code>
<custom_field name="Total_Components">1</custom_field>
<custom_field name="Total_Tracks">16</custom_field>
<genre>Pop/Rock</genre>
<artist name="Tseng, Shu Ching" ll_name="曾淑琴" role="Artist" />
<custom_field name="TPM_Code">11</custom_field>
<custom_field name="Release_Type_Code">AL</custom_field>
<track ll_title="不再等待天堂" number="1" title="Bu Zai Deng Dai Tian Tang">
<artist name="Tseng, Shu Ching" ll_name="曾淑琴" role="Artist" />
<custom_field name="Duration">235</custom_field>
<custom_field name="TPM_Code">11</custom_field>
<custom_field name="P_Notice">Digital Remaster (p) 2003 The Copyright in this sound recording is owned by a unit of EMI Music.</custom_field>
<custom_field name="Repertoire_Owner">EMI (TAIWAN) LTD</custom_field>
<custom_field name="Component_Number">1</custom_field>
<custom_field name="Hidden_Track_Flag">N</custom_field>
</track>
<track ll_title="天堂" number="1" title="Bu Zai Deng Dai Tian Tang">
<artist name="Tseng, Shu Ching" ll_name="曾淑琴" role="Artist" />
<custom_field name="Duration">235</custom_field>
<custom_field name="TPM_Code">11</custom_field>
<custom_field name="P_Notice">Digital Remaster (p) 2003 The Copyright in this sound recording is owned by a unit of EMI Music.</custom_field>
<custom_field name="Repertoire_Owner">EMI (TAIWAN) LTD</custom_field>
<custom_field name="Component_Number">1</custom_field>
<custom_field name="Hidden_Track_Flag">N</custom_field>
</track>
<track .....>
</track>
</master>
想读"master"下面部分子节点,其中"track"不定多。