以下面这个简单的XML文件为基础，给出一段能读取，修改该XML的java代码
最好是调试通过的…… 我是小白，自己不会整的；
具体实现功能：
1 新增加1个节点
<book id="B04">
<name> book4 </name>
<price> 40 </price>
<memo> This is book4 </memo>
</book>
2 修改节点1
<book id="B01">
<name> book1 </name>
<price> 100 </price>
<memo> This is book1 </memo>
</book>
3删除节点2
<book id="B02">
<name> book2 </name>
<price> 20 </price>
<memo> This is book2 </memo>
</book>
4最好是符合W3C规范的？
XML code
<?xml version="1.0" encoding="UTF-8"?>
<books>
<book id="B01">
<name>book1</name>
<price>10</price>
<memo>This is book1</memo>
</book>
<book id="B02">
<name>book2</name>
<price>20</price>
<memo>This is book2</memo>
</book>
<book id="B03">
<name>book3</name>
<price>30</price>
<memo>This is book3</memo>
</book>
</books>
