通过解析Xml配置文件，获取配置信息，进行实例化

package cn.itheima.web.servlet1;

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

public class TestMyServlet {

@Test
public void testMyServlet(){
try {
//1.创建解析器对象
SAXReader saxReader = new SAXReader();
//2.使用解析器加载web.xml文件得到document对象
Document document = saxReader.read("src/cn/itheima/web/servlet1/web.xml");
//3.获取根元素节点
Element rootElement = document.getRootElement();
//4.根据元素名称获取子元素节点
Element servletElement = rootElement.element("servlet");
//5.根据元素名称获取servlet-class的文本节点
String servletClass = servletElement.element("servlet-class").getText();
//System.out.println(servletClass);
//6.通过类全名获取字节码文件
Class clazz = Class.forName(servletClass);
//7.创建实例对象
MyServlet1 my = (MyServlet1) clazz.newInstance();
//8.调用实例对象里面的方法
my.init();
my.service();
my.destory();
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://www.example.org/web-app_2_5" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.example.org/web-app_2_5 web-app_2_5.xsd"
version="2.5">

<servlet>
<servlet-name>MyServlet1</servlet-name>
<servlet-class>cn.itheima.web.servlet1.MyServlet1</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>MyServlet1</servlet-name>
<url-pattern>/myServlet1</url-pattern>
</servlet-mapping>
<servlet>
<servlet-name>MyServlet2</servlet-name>
<servlet-class>cn.itheima.web.servlet1.MyServlet2</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>MyServlet2</servlet-name>
<url-pattern>/myServlet2</url-pattern>
</servlet-mapping>
</web-app>

package cn.itheima.web.servlet1;

public interface IMyServlet {

public void init();

public void service();

public void destory();
}

package cn.itheima.web.servlet1;

public class MyServlet1 implements IMyServlet{

@Override
public void init() {
System.out.println("MyServlet1诞生了……");
}

@Override
public void service() {
System.out.println("MyServlet1开始服务了……");
}

@Override
public void destory() {
System.out.println("MyServlet1销毁了……");
}

}

package cn.itheima.web.servlet1;

public class MyServlet2 implements IMyServlet{

@Override
public void init() {
System.out.println("MyServlet2诞生了……");
}

@Override
public void service() {
System.out.println("MyServlet2开始服务了……");
}

@Override
public void destory() {
System.out.println("MyServlet2销毁了……");
}

}