springboot注入servlet的方法

问：有了springMVC，为什么还要用servlet？有了servlet3的注解，为什么还要使用ServletRegistrationBean注入的方式？

使用场景：在有些场景下，比如我们要使用hystrix-dashboard，这时候就需要注入HystrixMetricsStreamServlet（第三方的servlet），该servlet是hystrix的组件。

一、代码

1、TestServlet（第一个servlet）

package com.xxx.secondboot.servlet;

import java.io.IOException;

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

public class TestServlet extends HttpServlet {

private static final long serialVersionUID = -4619665430596950563L;

@Override

protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

System.out.println("zhaojigang servlet");

}

@Override

protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

this.doGet(req, resp);

}

2、Testservlet2（第二个servlet）

package com.xxx.secondboot.servlet;

import java.io.IOException;

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

public class TestServlet2 extends HttpServlet {

private static final long serialVersionUID = 3788279972938793265L;

@Override

protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

System.out.println("zhaojigang servlet2");

}

@Override

protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

this.doGet(req, resp);

}

3、ServletConfig（servlet注入配置类）