Spring Boot 整合 Servlet、Filter、Listener

有的时候需要在 springboot 工程里面加入 Servlet、Filter 和 Listener 等

1. 环境准备 - 项目依赖

修改pom.xml文件，配置项目相关依赖

<dependencies>
    <!-- 引入web项目启动器 -->
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
    <!-- 引入spring boot的测试类 -->
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-test</artifactId>
        <scope>test</scope>
    </dependency>
</dependencies>

2. 整合步骤

1. 在项目的启动类上增加注解@ServletComponentScan(basePackages = {"xxx.xxx.xxx"}) ``` package com.moon.webcomponent;

import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; import org.springframework.boot.web.servlet.ServletComponentScan;

/**

• Spring Boot 整合 Servlet、Filter、Listener 启动类 */ @SpringBootApplication // @ServletComponentScan 注解作用是到扫描指定包中有@WebServlet、@WebFilter、@WebListener等注解的类 @ServletComponentScan(basePackages = {“com.moon.webcomponent”}) public class ComponentApplication { public static void main(String[] args) {

   SpringApplication.run(ComponentApplication.class, args);

  } }

2. 该注解会扫描指定包(basePackages)下面的注解
- `@WebServlet`
- `@WebFilter`
- `@WebListener`
创建自定义servlet

package com.moon.webcomponent.servlet;

import javax.servlet.ServletException; import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import java.io.IOException;

/**

• 自定义servlet / @WebServlet(urlPatterns = “/myservlet/“) public class MyServlet extends HttpServlet { @Override protected void doGet(HttpServletRequest req, HttpServletResponse resp)

       throws ServletException, IOException {
   System.out.println("-----------------MyServlet.doGet()-----------------------");

  }

  @Override protected void doPost(HttpServletRequest req, HttpServletResponse resp)

       throws ServletException, IOException {
   System.out.println("-----------------MyServlet.doPost()-----------------------");

  } }

创建自定义filter

package com.moon.webcomponent.filter;

import javax.servlet.Filter; import javax.servlet.FilterChain; import javax.servlet.ServletException; import javax.servlet.ServletRequest; import javax.servlet.ServletResponse; import javax.servlet.annotation.WebFilter; import java.io.IOException;

/**

• 自定义 Filter / @WebFilter(urlPatterns = “/“, filterName = “myFilter”) public class MyFilter implements Filter { @Override public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)

       throws IOException, ServletException {
   System.out.println("--------MyFilter----------");
   chain.doFilter(request, response);

  } }

创建自定义listener

package com.moon.webcomponent.listener;

import javax.servlet.ServletContextEvent; import javax.servlet.ServletContextListener; import javax.servlet.annotation.WebListener;

/**

• 自定义 Listenr *
• @author MoonZero
• @version 1.0
• @date 2020-3-15 12:11
• @description */ @WebListener public class MyListener implements ServletContextListener { @Override public void contextInitialized(ServletContextEvent sce) {

   System.out.println("================ MyListener.contextInitialized() 方法执行================");

  } @Override public void contextDestroyed(ServletContextEvent sce) {

   System.out.println("================ MyListener.contextDestroyed() 方法执行================");

  } }

```

3. 运行测试

• 在浏览器输入url：http://localhost:8080/myservlet/1
• 运行结果