spring boot——请求与参数校验——重要概念——配置Servlet、Filter、Listener——代码配置以及注解配置——华章

标签：华章 配置 public Listener println import servlet javax out

 

 

 

 

 

 

代码配置：

package org.example.webFilter.config;

import org.example.webFilter.filter.FirstFilter;
import org.example.webFilter.listener.FirstListener;
import org.example.webFilter.servlet.FirstServlet;
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.ServletContextListener;
import java.util.ArrayList;
import java.util.EventListener;
import java.util.List;

@Configuration
public class WebConfig {

    /**
     * servletRegistrationBean:(使用代码注册Servlet（不需要@ServletComponentScan注解）).
     */
    @Bean
    public ServletRegistrationBean getFirstServlet()
    {

        ServletRegistrationBean registrationBean = new ServletRegistrationBean();

        registrationBean.setServlet(new FirstServlet());

        List<String> urlMappings = new ArrayList<String>();

        // 访问，可以添加多个
        urlMappings.add("/first");
        registrationBean.setUrlMappings(urlMappings);

        // 设置加载顺序
        registrationBean.setLoadOnStartup(1);

        return registrationBean;
    }

    /**
     * 注册拦截器
     */
    @Bean
    public FilterRegistrationBean getFirstFilter()
    {

        FirstFilter demoFilter = new FirstFilter();

        FilterRegistrationBean registrationBean=new FilterRegistrationBean();

        registrationBean.setFilter(demoFilter);

        List<String> urlPatterns=new ArrayList<String>();

        //拦截路径，可以添加多个
        urlPatterns.add("/*");

        registrationBean.setUrlPatterns(urlPatterns);

        //设置注册顺序
        registrationBean.setOrder(1);

        return registrationBean;
    }

    /**
     * 注册监听器
     */
    @Bean
    public ServletListenerRegistrationBean<ServletContextListener> getFirstListener()
    {

        ServletListenerRegistrationBean<ServletContextListener> registrationBean = new ServletListenerRegistrationBean<>();

        registrationBean.setListener(new FirstListener());

        // 设置注册顺序
        registrationBean.setOrder(1);

        return registrationBean;
    }

}

 

 

 

 

 

 

 

 

代码里面设置：

package org.example.webFilter.servlet;

import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;

public class FirstServlet extends HttpServlet {

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        System.out.println("FirstServlet正在执行doGet");
        doPost(req, resp);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        System.out.println("FirstServlet正在执行doPost");
        //获取响应输出流PrinterWriter对象
        PrintWriter out = resp.getWriter();
        //使用输出流对象向客户端发送信息
        out.println("I'm a FirstServlet");//I'm a FirstServlet 会在客户端显示
    }

    @Override
    public void init(ServletConfig config) throws ServletException {
        System.out.println("FirstServlet正在执行init");
        super.init(config);
    }
}

 

 

 

注解设置：

package org.example.webFilter.servlet;

import javax.servlet.ServletConfig;
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;
import java.io.PrintWriter;

@WebServlet(urlPatterns = "/second")
public class SecondServlet extends HttpServlet {

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        System.out.println("SecondServlet正在执行doGet");
        doPost(req,resp);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        System.out.println("SecondServlet正在执行doPost");
        //获取响应输出流PrinterWriter对象
        PrintWriter out = resp.getWriter();
        //使用输出流对象向客户端发送信息
        out.println("I'm a SecondServlet");//I'm a SecondServlet 会在客户端显示
    }

    @Override
    public void init(ServletConfig config) throws ServletException {
        System.out.println("SecondServlet正在执行init");
        super.init(config);
    }

}

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

package org.example.webFilter.filter;

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

public class FirstFilter implements Filter {

    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
        System.out.println("FirstFilter正在执行doFilter");
        chain.doFilter(request, response);//放行
    }

    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
        System.out.println("FirstFilter正在执行init");
    }

    @Override
    public void destroy() {
        System.out.println("FirstFilter正在执行destroy");
    }
}

 

 

 

 

 

 

 

package org.example.webFilter.filter;

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

@WebFilter(filterName = "secondFilter", urlPatterns = "/*")
public class SecondFilter implements Filter {

    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
        System.out.println("SecondFilter正在执行doFilter");
        chain.doFilter(request, response);//放行
    }

    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
        System.out.println("SecondFilter正在执行init");
    }

    @Override
    public void destroy() {
        System.out.println("SecondFilter正在执行destroy");
    }
}

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

package org.example.webFilter.servlet;

import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;

public class FirstServlet extends HttpServlet {

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        System.out.println("FirstServlet正在执行doGet");
        doPost(req, resp);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        System.out.println("FirstServlet正在执行doPost");
        //获取响应输出流PrinterWriter对象
        PrintWriter out = resp.getWriter();
        //使用输出流对象向客户端发送信息
        out.println("I'm a FirstServlet");//I'm a FirstServlet 会在客户端显示
    }

    @Override
    public void init(ServletConfig config) throws ServletException {
        System.out.println("FirstServlet正在执行init");
        super.init(config);
    }
}

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

package org.example.webFilter.servlet;

import javax.servlet.ServletConfig;
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;
import java.io.PrintWriter;

@WebServlet(urlPatterns = "/second")
public class SecondServlet extends HttpServlet {

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        System.out.println("SecondServlet正在执行doGet");
        doPost(req,resp);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        System.out.println("SecondServlet正在执行doPost");
        //获取响应输出流PrinterWriter对象
        PrintWriter out = resp.getWriter();
        //使用输出流对象向客户端发送信息
        out.println("I'm a SecondServlet");//I'm a SecondServlet 会在客户端显示
    }

    @Override
    public void init(ServletConfig config) throws ServletException {
        System.out.println("SecondServlet正在执行init");
        super.init(config);
    }

}

 

 

 

 

 

 

 

 

package org.example;

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


@SpringBootApplication
@ServletComponentScan("org.example.webFilter")
public class HelloWorldApplication
{

    public static void main(String[] args)
    {

        SpringApplication.run(HelloWorldApplication.class, args);

    }
}

 

 

 

 

 

 

 

 

 

 

 

package org.example.webFilter.listener;

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

public class FirstListener implements ServletContextListener {

    @Override
    public void contextInitialized(ServletContextEvent sce) {
        System.out.println("FirstListener监听器正在初始化");
        System.out.println("servlet container："+sce.getServletContext().getServerInfo());
    }

    @Override
    public void contextDestroyed(ServletContextEvent sce) {
        System.out.println("FirstListener监听器正在 销毁");
    }
}

 

 

 

 

 

 

 

 

 

 

package org.example.webFilter.listener;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;
import javax.servlet.annotation.WebListener;
import javax.servlet.http.HttpSessionEvent;
import javax.servlet.http.HttpSessionListener;

@WebListener
public class SecondListener implements ServletContextListener {

    @Override
    public void contextInitialized(ServletContextEvent sce) {
        System.out.println("SecondListener监听器正在初始化");
        System.out.println("servlet container："+sce.getServletContext().getServerInfo());
    }

    @Override
    public void contextDestroyed(ServletContextEvent sce) {
        System.out.println("SecondListener监听器正在 销毁");
    }
}

 

标签：华章,配置,public,Listener,println,import,servlet,javax,out
From： https://www.cnblogs.com/xiaobaibailongma/p/17065071.html