android学习四:xml

主要是想简单的学习xml的解析。

服务器端直接放两个xml文件。我们的app客户端通过http get的方式得到两个文件的内容。如下。

person.xml

<?xml version="1.0" encoding="UTF-8"?>
<persons>
<person id = "23">
<name>张老师</name>
<age>21</age>
</person>
<person id = "20">
<name>李老师</name>
<age>25</age>
</person>
</persons>

book.xml

<?xml version="1.0" encoding="UTF-8"?>
<books>
<book id="10">
<name> java </name>
<price>12.0</price>
</book>

<book id="11">
<name> C++ </name>
<price>13.0</price>
</book>
</books>

客户端解析下面的数据。

1、使用SAX解析 person.xml

2、使用dom解析book.xml

根据xml可以新建一个类Book

public class Book {

private int id;
private String name;
private float price;

public int getId() {
return id;
}

public void setId(int id) {
this.id = id;
}

public String getName() {
return name;
}

public void setName(String name) {
this.name = name;
}

public float getPrice() {
return price;
}

public void setPrice(float price) {
this.price = price;
}

@Override
public String toString() {
return this.id + ":" + this.name + ":" + this.price;
}
}从xml文件里面获取到InputStream。下面对InputStream进行解析。原理不是很了解。但是套用还是可以使用的。

public List<Book> getBooks(InputStream inputStream) throws Exception {
<span style="white-space:pre">		</span>List<Book> list = new ArrayList<Book>();
<span style="white-space:pre">		</span>/** 下面的四个语句基本固定的 */
<span style="white-space:pre">		</span>DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
<span style="white-space:pre">		</span>DocumentBuilder builder = factory.newDocumentBuilder();
<span style="white-space:pre">		</span>Document document = builder.parse(inputStream);
<span style="white-space:pre">		</span>Element element = document.getDocumentElement();

<span style="white-space:pre">		</span>/** 每个book节点下面的所有内容的list集合 */
<span style="white-space:pre">		</span>NodeList bookNodes = element.getElementsByTagName("book");
<span style="white-space:pre">		</span>for (int i = 0; i < bookNodes.getLength(); i++) {
<span style="white-space:pre">			</span>/** 获取每个book */
<span style="white-space:pre">			</span>Element bookElement = (Element) bookNodes.item(i);
<span style="white-space:pre">			</span>Book book = new Book();
<span style="white-space:pre">			</span>/** book的属性 */
<span style="white-space:pre">			</span>book.setId(Integer.parseInt(bookElement.getAttribute("id")));
<span style="white-space:pre">			</span>/** book的子节点 */
<span style="white-space:pre">			</span>NodeList childNodes = bookElement.getChildNodes();
<span style="white-space:pre">			</span>for (int j = 0; j < childNodes.getLength(); j++) {
<span style="white-space:pre">				</span>if (childNodes.item(j).getNodeType() == Node.ELEMENT_NODE) {
<span style="white-space:pre">					</span>if ("name".equals(childNodes.item(j).getNodeName())) {
<span style="white-space:pre">						</span>book.setName(childNodes.item(j).getFirstChild()
<span style="white-space:pre">								</span>.getNodeValue());
<span style="white-space:pre">					</span>} else if ("price".equals(childNodes.item(j).getNodeName())) {
<span style="white-space:pre">						</span>book.setPrice(Float.parseFloat(childNodes.item(j)
<span style="white-space:pre">								</span>.getFirstChild().getNodeValue()));
<span style="white-space:pre">					</span>}
<span style="white-space:pre">				</span>}
<span style="white-space:pre">			</span>}
<span style="white-space:pre">			</span>list.add(book);
<span style="white-space:pre">		</span>}
<span style="white-space:pre">		</span>return list;
<span style="white-space:pre">	</span>}