JavaWeb - Servlet之全局转发器（反射）

package com.imooc.sm.global;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import javax.servlet.GenericServlet;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
public class DispatcherServlet extends GenericServlet {
    private ApplicationContext context;
    public void init() throws ServletException {
        super.init();
        context = new ClassPathXmlApplicationContext("spring.xml");
    }
    public void service(ServletRequest servletRequest, ServletResponse servletResponse) throws ServletException, IOException {
        HttpServletRequest request = (HttpServletRequest) servletRequest;
        HttpServletResponse response = (HttpServletResponse) servletResponse;
        String path = request.getServletPath().substring(1);
        String beanName = null;
        String methodName = null;
        int index = path.indexOf('/');
        if (index != -1) {
            beanName = path.substring(0, index) + "Controller";
            methodName = path.substring(index + 1, path.indexOf(".do"));
        } else {
            beanName = "selfController";
            methodName = path.substring(0, path.indexOf(".do"));
        }
        Object obj = context.getBean(beanName);
        try {
            Method method = obj.getClass().getMethod(methodName,HttpServletRequest.class,HttpServletResponse.class);
            method.invoke(obj,request,response);
        } catch (NoSuchMethodException e) {
            e.printStackTrace();
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        } catch (InvocationTargetException e) {
            e.printStackTrace();
        }
    }
}

<servlet>
  <servlet-name>Global</servlet-name>
  <servlet-class>com.imooc.sm.global.DispatcherServlet</servlet-class>
</servlet>
<servlet-mapping>
  <servlet-name>Global</servlet-name>
  <url-pattern>*.do</url-pattern>
</servlet-mapping>