xml的一个例子1.读取第二个book元素的price元素值

2.给第一个book元素的price元素添加一个属性danwei,值为rmb

3.添加一个book元素，包括name子元素和price子元素，值分别为ppp和45.67-1 An example of xml. read the second book element of the price element of the value of 2. to the first book element in the price element add an attribute danwei, a value of rmb3. add a book element, including the name and price subelement subelement, ppp and the values were 45.67