springboot注入servlet的方法

时间:2021-10-14 16:33:00

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)

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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(第二个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注入配置类)

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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;
 
@Configuration
public 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;
  }
  
}

说明:使用ServletRegistrationBean来注入servlet,对于每一个servlet都有一个ServletRegistrationBean来注入。

注意:如果只是自己要使用servlet,可以直接只用servlet3的注解来声明servlet就好,但是像HystrixMetricsStreamServlet这样的第三方servlet,就只能通过上边这样的方式来搞了。

 二、测试

启动服务,浏览器输入"http://localhost:8083/servlet/test","http://localhost:8083/servlet/test2",查看console的输出。

以上就是本文的全部内容,希望对大家的学习有所帮助,也希望大家多多支持服务器之家。

原文链接:http://www.cnblogs.com/java-zhao/p/5775103.html