SpringBoot学习笔记12-SpringBoot 中使用 Filter

通过2种方式实现
方式一,通过注解方式实现；
1、编写一个Servlet3的注解过滤器；
创建一个filter包。

package com.springboot.web.filter;

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

@WebFilter(urlPatterns="/*")
public class MyFilter implements Filter {
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
    }
    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
            throws IOException, ServletException {
        System.out.println("您已进入filter过滤器，您的请求正常，请继续遵规则...");
        chain.doFilter(request, response);
    }
    @Override
    public void destroy() {
    }
}

2、在main方法的主类上添加注解：

@ServletComponentScan(basePackages={"com.springboot.web.servlet","com.springboot.web.filter"})

运行截图如下：

方式二，通过Spring boot的配置类实现；
1、编写一个普通的Filter

package com.springboot.web.filter;

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

public class HeFilter implements Filter {
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
    }
    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
            throws IOException, ServletException {
        System.out.println("hi您已进入filter过滤器，您的请求正常，请继续遵规则...");
        chain.doFilter(request, response);
    }
    @Override
    public void destroy() {
    }
}

2、编写一个Springboot的配置类；
编写个ServletConfig配置类，注意一定要加@Configuration

package com.springboot.web.config;

import com.springboot.web.filter.HeFilter;
import com.springboot.web.servlet.HeServlet;
import org.springframework.boot.web.servlet.FilterRegistrationBean;
import org.springframework.boot.web.servlet.ServletRegistrationBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

/** springboot没有xml ， @Configuration可以表示一个spring的配置文件，比如：applicationContext.xml */
@Configuration //一定要加上这个注解，成为Springboot的配置类，不然不会生效
public class ServletConfig {

    @Bean //这个注解就将这个ServletRegistrationBean变成一个Spring的bean类。
    public ServletRegistrationBean heServletRegistrationBean(){
        ServletRegistrationBean registration = new ServletRegistrationBean(new HeServlet(), "/heServlet");
        return registration;
    }

    @Bean
    public ServletRegistrationBean sheServletRegistrationBean(){
        ServletRegistrationBean registration = new ServletRegistrationBean(new HeServlet(), "/sheServlet");
        return registration;
    }
    @Bean
    public FilterRegistrationBean heFilterRegistration() {
        FilterRegistrationBean registration = new FilterRegistrationBean(new HeFilter());
        registration.addUrlPatterns("/*");
        return registration;
    }

}

运行截图如下：