SpringBoot 配置自定义servlet

SpringBoot中有内置的servlet容器

一、如何指定和修改Servlet容器的相关配置

可以在application.properties中修改servlet容器的配置

// 通用的Servlet容器设置 server.xxx
server.port=8080
server.servlet.context-path=/me

// Tomcat的设置 server.tomcat.xxx
server.tomcat.uri-encoding=utf-8

二、怎样自定义servlet、filter、listener组件

主要分为两步：
1、编写自定义组件
2、注册组件

• 1.1自定义servlet

public class MyServlet extends HttpServlet {

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doPost(req, resp);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        resp.getWriter().write("hello servlet");
    }
}

• 1.2自定义filter

import javax.servlet.*;
import java.io.IOException;

public class MyFilter implements Filter {
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
        System.out.println("初始化filter");
    }

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        System.out.println("进入filter。。。");
        filterChain.doFilter(servletRequest,servletResponse);//进入下一个filter
    }

    @Override
    public void destroy() {
        System.out.println("销毁filter");
    }
}

• 1.3自定义listener

import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;

public class MyListener implements ServletContextListener {

    @Override
    public void contextInitialized(ServletContextEvent sce) {
        System.out.println("监听器已启动。。。");
    }

    @Override
    public void contextDestroyed(ServletContextEvent sce) {
        System.out.println("当前监听器已销毁");
    }
}

• 2.1注册自定义的组件
  主要应用到的组件是：
  ServletRegistrationBean
  FilterRegistrationBean
  ServletListenerRegistrationBean

import com.mystudy.springboot.config.filter.MyFilter;
import com.mystudy.springboot.config.listener.MyListener;
import com.mystudy.springboot.config.servlet.MyServlet;
import org.springframework.boot.web.servlet.FilterRegistrationBean;
import org.springframework.boot.web.servlet.ServletListenerRegistrationBean;
import org.springframework.boot.web.servlet.ServletRegistrationBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

import javax.servlet.Filter;
import java.util.Arrays;
import java.util.EventListener;

@Configuration
public class MyServer {

    // 注册自定义servlet
    @Bean
    public ServletRegistrationBean myServlet(){
        ServletRegistrationBean servletRegistrationBean = new ServletRegistrationBean();
        servletRegistrationBean.setServlet(new MyServlet()); // 添加自定义的servlet
        // 设置自定义servlet的访问路径
        servletRegistrationBean.setUrlMappings(Arrays.asList("/myServlet"));
        return servletRegistrationBean;
    }

    // 注册自定义filter
    @Bean
    public FilterRegistrationBean myFilter(){
        FilterRegistrationBean<Filter> filterFilterRegistrationBean = new FilterRegistrationBean<>();
        filterFilterRegistrationBean.setFilter(new MyFilter());// 添加自定义的filter
        // 指定需要进行过滤的请求路径
        filterFilterRegistrationBean.setUrlPatterns(Arrays.asList("/hello","/myServlet"));
        return filterFilterRegistrationBean;
    }

    // 注册自定义监听器
    @Bean
    public ServletListenerRegistrationBean myListener(){
        ServletListenerRegistrationBean<EventListener> eventListener = new ServletListenerRegistrationBean<>();
        eventListener.setListener(new MyListener());// 添加自定义的listener
        return eventListener;

    }
    
}