springboot整合servlet、filter、interceptor

Servlet

方式一：xml注入

package com.lee.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;

/**
 * springboot整合servlet的第一种方式：
 *   原来
 *      <servlet>
 *          <servlet-name>firstServlet</servlet-name>
 *          <servlet-class>com.lee.FirstServlet</servlet-class>
 *      </servlet>
 *      <servlet-mapping>
 *          <servlet-name>firstServlet</servlet-name>
 *          <url-pattern>/firstServlet</url-pattern>
 *      </servlet-mapping>
 */

@WebServlet(name="firstServlet",urlPatterns = "/firstServlet")
public class FirstServlet extends HttpServlet {

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

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        System.out.println("firstServlet............");
    }
}

package com.lee;

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

//该注解会扫描当前包和其子包下的 @WebServlet,
//并在启动类启动的时候将其实例化
@ServletComponentScan
@SpringBootApplication
public class SpringbootApplicationServlet1 {

    public static void main(String[] args) {
        SpringApplication.run(SpringbootApplicationServlet1.class,args);
    }
}

方式二：bean注入

package com.lee.servlet;

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

public class SecondServlet extends HttpServlet {

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

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        System.out.println("secondServlet....");
    }
}

package com.lee;

import com.lee.servlet.SecondServlet;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.web.servlet.ServletRegistrationBean;
import org.springframework.context.annotation.Bean;

@SpringBootApplication
public class SpringbootApplicationServlet2 {

    public static void main(String[] args) {
        SpringApplication.run(SpringbootApplicationServlet2.class,args);
    }

    //将scondServlet注册到servletRegistrationBean中
    @Bean
    public ServletRegistrationBean secondServlet(){
        ServletRegistrationBean bean = new ServletRegistrationBean();
        bean.setServlet(new SecondServlet());
        bean.addUrlMappings("/secondServlet");
        return bean;
    }
}

Filter

方式一：xml注入

package com.lee.filter;

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

/**
 * <filter>
 *     <filter-name>FirstFilter</filter-name>
 *     <filter-class>com.lee.filter.FirstFilter</filter-class>
 * </filter>
 * <filter-mapping>
 *     <filter-name>FirstFilter</filter-name>
 *     <url-patter>/firstServlet</url-patter>
 * </filter-mapping>
 */
//@WebFilter(filterName = "firstFilter",urlPatterns = {"*.do","*.action"})
@WebFilter(filterName = "firstFilter",urlPatterns = "/firstServlet")
public class FirstFilter implements Filter {

    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
        System.out.println(" first filter init");
    }

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        System.out.println("enter first filter");
        filterChain.doFilter(servletRequest, servletResponse);
        System.out.println("leave first filter");
    }

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

package com.lee;

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

//该注解会扫描当前包和其子包下的 @WebServlet @WebFilter等,
//并在启动类启动的时候将其实例化
@ServletComponentScan
@SpringBootApplication
public class SpringbootApplicationFilter1 {

    public static void main(String[] args) {
        SpringApplication.run(SpringbootApplicationFilter1.class,args);
    }
}

方式二：bean注入

package com.lee.filter;

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

public class SecondFilter implements Filter {

    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
        System.out.println(" second filter init");
    }

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        System.out.println("enter second filter");
        filterChain.doFilter(servletRequest, servletResponse);
        System.out.println("leave second filter");
    }

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

package com.lee;

import com.lee.filter.SecondFilter;
import com.lee.servlet.SecondServlet;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.web.servlet.FilterRegistrationBean;
import org.springframework.boot.web.servlet.ServletRegistrationBean;
import org.springframework.context.annotation.Bean;

@SpringBootApplication
public class SpringbootApplicationFilter2 {

    public static void main(String[] args) {
        SpringApplication.run(SpringbootApplicationFilter2.class,args);
    }

    //将scondServlet注册到servletRegistrationBean中
    @Bean
    public ServletRegistrationBean secondServlet(){
        ServletRegistrationBean bean = new ServletRegistrationBean();
        bean.setServlet(new SecondServlet());
        bean.addUrlMappings("/secondServlet");
        return bean;
    }

    @Bean
    public FilterRegistrationBean secondFilter(){
        FilterRegistrationBean bean = new FilterRegistrationBean();
        bean.setFilter(new SecondFilter());
        bean.addUrlPatterns("/secondServlet");
        return bean;
    }
}

interceptor

public class MyInterceptor implements HandlerInterceptor {
 
    private final Logger logger = LoggerFactory.getLogger(this.getClass().getCanonicalName());
 
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object o) throws Exception {
        logger.info("{}:在请求处理之前进行调用（Controller方法调用之前）", this.getClass().getSimpleName());
        return true;//只有返回true才会继续向下执行，返回false取消当前请求
    }
 
    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object o, ModelAndView modelAndView) throws Exception {
        logger.info("{}:请求处理之后进行调用，但是在视图被渲染之前（Controller方法调用之后）", this.getClass().getSimpleName());
    }
 
    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object o, Exception e) throws Exception {
        logger.info("{}:在整个请求结束之后被调用，也就是在DispatcherServlet 渲染了对应的视图之后执行（主要是用于进行资源清理工作）", this.getClass().getSimpleName());
    }
}

@Configuration
public class WebMvcConfig extends WebMvcConfigurerAdapter{
 
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(new MyInterceptor()).addPathPatterns("/**");//用于添加拦截规则
        // 多个拦截器组成一个拦截器链
        // excludePathPatterns 用户排除拦截
    }
}