Mybatis学习--7.解析Mybatis配置文件

解析MyBatis配置文件

#####解析核心配置文件

package com.deng.testmybatisxml;

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

import java.io.InputStream;
import java.util.List;

public class ParseXmlByDom4jTest {
    @Test
    public void testMybatisXmlConfig() throws Exception{
        //获取SAXReader 对象
        SAXReader reader = new SAXReader();
        //获取mybatis-config.xml文件对象
        InputStream is = ClassLoader.getSystemClassLoader().getResourceAsStream("mybatis-config.xml");
        Document document = reader.read(is);
        //获取文件的根标签
        Element rootElement = document.getRootElement();
        String rootName = rootElement.getName();
        System.out.println(rootName);//configuration
        //获取根标签内部的单个子标签，通过路径定位标签
        String xpath = "/" + rootName + "/environments";
        Element environments = (Element)document.selectSingleNode(xpath);
        String environmentsName = environments.getName();
        System.out.println(environmentsName);//environments
        //获得environments的default属性
        String Default = environments.attributeValue("default");
        System.out.println(Default);//development
        //根据defaults获取environments中对应的environment标签
        String xpath1 = "/" + rootName + "/" + environmentsName +
                "/environment[@id='"+Default+"']";
        Element environment = (Element)document.selectSingleNode(xpath1);
        //获取environment标签中的子标签
        Element transcationManager = environment.element("transactionManager");
        System.out.println(transcationManager.getName());//transactionManager
        //获得其属性
        String type = transcationManager.attributeValue("type");
        System.out.println(type);//JDBC
        //不想从根标签下获得其子标签
        String xpath2 = "//mappers";
        Element mappers = (Element) document.selectSingleNode(xpath2);
        System.out.println(mappers.getName());
    }
}
//可通过 父标签.element("子标签名");