問：有了springMVC，為什么還要用servlet？有了servlet3的注解，為什么還要使用ServletRegistrationBean注入的方式？
使用場景：在有些場景下，比如我們要使用hystrix-dashboard，這時候就需要注入HystrixMetricsStreamServlet（第三方的servlet），該servlet是hystrix的組件。
一、代碼
1、TestServlet（第一個servlet）
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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（第二個servlet）
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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注入配置類）
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package com.xxx.secondboot.servlet;import org.springframework.boot.context.embedded.ServletRegistrationBean;import org.springframework.context.annotation.Bean;import org.springframework.context.annotation.Configuration;@Configurationpublic class ServletConfig { @Bean public TestServlet testServlet(){ return new TestServlet(); } @Bean public ServletRegistrationBean testServletRegistrationBean(TestServlet testServlet){ ServletRegistrationBean registration = new ServletRegistrationBean(testServlet); registration.setEnabled(true); registration.addUrlMappings("/servlet/test"); return registration; } /********************************************/ @Bean public TestServlet2 testServlet2(){ return new TestServlet2(); } @Bean public ServletRegistrationBean test2ServletRegistrationBean(TestServlet2 testServlet2){ ServletRegistrationBean registration = new ServletRegistrationBean(testServlet2); registration.setEnabled(true); registration.addUrlMappings("/servlet/test2"); return registration; } } |
說明：使用ServletRegistrationBean來注入servlet，對于每一個servlet都有一個ServletRegistrationBean來注入。
注意：如果只是自己要使用servlet，可以直接只用servlet3的注解來聲明servlet就好，但是像HystrixMetricsStreamServlet這樣的第三方servlet，就只能通過上邊這樣的方式來搞了。
二、測試
啟動服務，瀏覽器輸入"http://localhost:8083/servlet/test","http://localhost:8083/servlet/test2"，查看console的輸出。
以上就是本文的全部內容，希望對大家的學習有所幫助，也希望大家多多支持服務器之家。
原文鏈接：http://www.cnblogs.com/java-zhao/p/5775103.html
