DOM4J_Xpath
XPath 使用路径表达式在 XML 文档中进行导航
XPath 包含一个标准函数库
XPath 是 XSLT 中的主要元素
XPath 是一个 W3C 标准
第一步：导入xpath的支持包
第二步：使用xpath
1:定义xpath = "//name"
2:查询 dom.selectNodes(xpath);
public class Demo03_Xpath {
@Test
public void test1() throws Exception {
SAXReader sax = new SAXReader();
Document dom = sax.read("./files/users.xml");
String xpath = "//name";
List<Element> list = dom.selectNodes(xpath);
for(Element e:list){
System.err.println(e.getText());
}
}
}
用xpath实现登录：
@Test
public void test2() throws Exception {
SAXReader sax = new SAXReader();
Document dom = sax.read("./files/users.xml");
String xpath = "//user[name='张三'][pwd='22225666']";
Element e = (Element) dom.selectSingleNode(xpath);
System.err.println(e);
}
模糊查询：
@Test
public void test3() throws Exception {
SAXReader sax = new SAXReader();
Document dom = sax.read("./files/users.xml");
String xpath = "//user[contains(name,'赵')][contains(age,'3')]";
List<Element> list = dom.selectNodes(xpath);
for(Element e:list){
System.err.println(e.asXML());
System.err.println("-----------------------");
}
}
根据id查询：
@Test
public void test4() throws Exception {
SAXReader sax = new SAXReader();
Document dom = sax.read("./files/users.xml");
String xpath = "//user[@id='U001']";
Element e = (Element) dom.selectSingleNode(xpath);
System.err.println(e.asXML());
}