springboot中编写过滤器Filter以及配置

简单方式: 继承Filter 以及添加@component注解即可

    package com.imooc.demo.filter;
import org.springframework.stereotype.Component;
import javax.servlet.*;
import java.io.IOException;
/**
 *  第一种方式:
 *  springboot中做过滤器 , 直接继承filter , 添加component注解即可
 *  第二种方式 -> 如 MyFilter2 与 config包下 . 将第三方过滤器添加入过滤器链中
 *
 *  过滤器的缺点:
 *      1. 只能获取request 与 response对象 . 并不能获取要访问的类与方法.
 *      2. 因为继承的filter是servlet的 , 并不是spring的
 *      3. 可以使用spring提供的拦截器 intercept
 */
@Component
public class MyFilter implements Filter{
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
        System.out.println("init...");
    }

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

    @Override
    public void destroy() {
        System.out.println("毁灭中...");
    }
}

2.1. 可配置方式.,通过使用@configuration注解实现

package com.imooc.demo.filter;

import org.springframework.stereotype.Component;

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

/**
 *
 */
public class MyFilter2 implements Filter{
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
        System.out.println("init...");
    }
    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        System.out.println("过滤器....");
        filterChain.doFilter(servletRequest,servletResponse);
    }
    @Override
    public void destroy() {
        System.out.println("毁灭中...");
    }
}

2.2 webconfig配置对象

package com.imooc.demo.filter.config;
import com.imooc.demo.filter.MyFilter2;
import org.springframework.boot.web.servlet.FilterRegistrationBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import java.util.ArrayList;
import java.util.List;
@Configuration
public class Webconfig {
    /**
     *  配置自定义过滤器或者第三方提供的过滤器
     * @return
     */
    @Bean
    public FilterRegistrationBean MyFilter() {
        // 此对象效果等同于 web.xml中的过滤器的配置
        FilterRegistrationBean filterRegistrationBean = new FilterRegistrationBean();
        MyFilter2 myFilter2 = new MyFilter2();
        filterRegistrationBean.setFilter(myFilter2);
        // 指定过滤url
        List<String> urls = new ArrayList<>();
        urls.add("/*");
        filterRegistrationBean.setUrlPatterns(urls);
        return filterRegistrationBean;
    }
}

springboot中编写过滤器Filter以及配置

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