java基础 xml 使用dom4j解析 xml文件 servlet根据pattern 找到class

Posted 2020-10-27 Advancing Swift

package com.swift.kaoshi;

import java.io.File;
import java.util.List;
import java.util.Scanner;

import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.Element;
import org.dom4j.io.SAXReader;
import org.junit.Test;

/*
<servlets>
    <servlet>
        <servlet-name>servlet1</servlet-name>
        <servlet-class>cn.itheima.servlets.MyServlet1</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>servlet1</servlet-name>
        <url-pattern>/s1</url-pattern>
    </servlet-mapping>
    <servlet>
        <servlet-name>servlet2</servlet-name>
        <servlet-class>cn.itheima.servlets.MyServlet2</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>servlet2</servlet-name>
        <url-pattern>/s2</url-pattern>
    </servlet-mapping>
</servlets>

二、编写程序，请按以下要求解析XML文件：
1.    接收用户输入一个字符串，例如：”/s1”，要求程序可以通过检索<servlet-mapping>元素下的<url-pattern>元素进匹配，匹配后获取同级的<servlet-name>元素的值；
通过这个值再检索<servlet>元素下的<servlet-name>元素的值进行匹配，匹配成功后，获取同级下的<url-pattern>的值，并打印<url-pattern>的值。<servlet-class>
例如：用户输入：/s1，控制台打印：cn.itheima.servlets.MyServlet1
      用户输入：/s2，控制台打印：cn.itheima.servlets.MyServlet2*/

//dom4j SAX遍历

public class Demo_Dom4j {

    public static void main(String[] args) throws Exception {

//        SAXReader reader = new SAXReader();
//        Document document = reader.read(new File("web.xml"));
//        String servlet_name = null;
//        
//        System.out.println("请输入一个路径字符串:");
//        Scanner scan = new Scanner(System.in);
//        String str = scan.nextLine();
//
//        Element root = document.getRootElement();
//        List<Element> mappings = root.elements("servlet-mapping");
//        for (Element element : mappings) {
//            System.out.println(element);
//            List<Element> urls = element.elements("url-pattern");
//            for (Element url : urls) {
//                System.out.println(url);
//                String text=url.getText();
//                System.out.println(text);
//                if(text.equals(str)) {
//                    Element name=element.element("servlet-name");
//                    servlet_name=name.getText();
//                    System.out.println(servlet_name);
//                }
//            }
//        }
//        System.out.println("===========================================================================");
//        //准备检索servlet
//        List<Element> servlets=root.elements("servlet");
//        for(Element servlet:servlets) {
//            System.out.println(servlet);
//            List<Element> servlet_names=servlet.elements("servlet-name");
//            for(Element servlet_n:servlet_names) {
//                String servlet_name1=servlet_n.getText();
//                System.out.println(servlet_name1);
//                if(servlet_name1.equals(servlet_name)) {
//                    Element servlet_class=servlet.element("servlet-class");
//                    System.out.println("需要查找的类的名称是: "+servlet_class.getText());
//                }
//            }
//        }

    }

    @Test
    public void show() throws Exception {
        
        SAXReader reader = new SAXReader();
        Document document = reader.read(new File("web.xml"));
        String servlet_name = null;
        
        System.out.println("请输入一个路径字符串:");
        Scanner scan = new Scanner(System.in);
        String str = scan.nextLine();

        Element root = document.getRootElement();
        List<Element> mappings = root.elements("servlet-mapping");
        for (Element element : mappings) {
            System.out.println(element);
            List<Element> urls = element.elements("url-pattern");
            for (Element url : urls) {
                System.out.println(url);
                String text=url.getText();
                System.out.println(text);
                if(text.equals(str)) {
                    Element name=element.element("servlet-name");
                    servlet_name=name.getText();
                    System.out.println(servlet_name);
                }
            }
        }
        System.out.println("===========================================================================");
        //准备检索servlet
        List<Element> servlets=root.elements("servlet");
        for(Element servlet:servlets) {
            System.out.println(servlet);
            List<Element> servlet_names=servlet.elements("servlet-name");
            for(Element servlet_n:servlet_names) {
                String servlet_name1=servlet_n.getText();
                System.out.println(servlet_name1);
                if(servlet_name1.equals(servlet_name)) {
                    Element servlet_class=servlet.element("servlet-class");
                    System.out.println("需要查找的类的名称是: "+servlet_class.getText());
                }
            }
        }
        
    }
}