SpringBoot學習筆記12-SpringBoot 中使用 Filter

通過2種方式實現
方式一,通過註解方式實現；
1、編寫一個Servlet3的註解過濾器；
創建一個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("您已進入filter過濾器，您的請求正常，請繼續遵規則...");
        chain.doFilter(request, response);
    }
    @Override
    public void destroy() {
    }
}

2、在main方法的主類上添加註解：

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

運行截圖如下：

方式二，通過Spring boot的配置類實現；
1、編寫一個普通的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您已進入filter過濾器，您的請求正常，請繼續遵規則...");
        chain.doFilter(request, response);
    }
    @Override
    public void destroy() {
    }
}

2、編寫一個Springboot的配置類；
編寫個ServletConfig配置類，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沒有xml ， @Configuration可以表示一個spring的配置文件，比如：applicationContext.xml */
@Configuration //一定要加上這個註解，成爲Springboot的配置類，不然不會生效
public class ServletConfig {

    @Bean //這個註解就將這個ServletRegistrationBean變成一個Spring的bean類。
    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;
    }

}

運行截圖如下：