dom4j---three利用XPath简化版

//利用Xpath找出第二本书的书名
    @Test
    public void test1() throws Exception{
        SAXReader reader=new SAXReader();
        Document document=reader.read("src/Demo2.xml");
        Element book_2=(Element)document.selectNodes("//书名").get(1);
        String text_value=book_2.getText();
        System.out.println(text_value);
    }

@Test
    public void test() throws Exception{
        //username和password 是通过用户提交得来的数据
        String username="aaa";
        String password="123";
        //验证这个是否正确
        SAXReader reader=new SAXReader();
        Document document=reader.read("src/user.xml");
        Node node=document.selectSingleNode("//user[@username='"+username+"' and @password='"+password+"']");
        if(node!=null){
            System.out.println("正确");
        }
        
        else System.out.println("验证失败");
    }