学习spring boot-拦截器Interceptor，过滤器Filter

目录

拦截器Interceptor

过滤器Filter

关于过滤器的前置知识可以参考：

过滤器在springboot项目的应用

一，使用@Webfilter+@ServletComponentScan 注解

1 创建过滤器类实现Filter接口

2 在启动类中添加 @ServletComponentScan 注解

二，创建过滤器配置类，注册过滤器

1 创建过滤器类（不添加WebFilter注解）

2创建配置类， 注册过滤器类

拦截器Interceptor

可以参考 springmvc-拦截器-CSDN博客

过滤器Filter

关于过滤器的前置知识可以参考：

javaWeb之过滤器（Filter）_javaweb中filter过滤器对象什么时候创建?-CSDN博客

过滤器在springboot项目的应用

一，使用@Webfilter+@ServletComponentScan 注解

1 创建过滤器类实现Filter接口

• 指定过滤器顺序（补充）。若存在多个过滤器且执行顺序重要，可使用@Order注解指定顺序。数字越小优先级越高。如@Order(1) 。

package com.it.heima.springboot06filter.filter;

import jakarta.servlet.*;
import jakarta.servlet.annotation.WebFilter;

import java.io.IOException;
@WebFilter("/user/*")
public class UserFilter implements Filter {
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
        System.out.println("正在初始化~~~~~~");
    }

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        System.out.println("是否满足条件");
        System.out.println("如满足条件放行~~~~~~~~");
        filterChain.doFilter(servletRequest,servletResponse);
    }

    @Override
    public void destroy() {
        System.out.println("正在销毁~~~~~~");

    }
}

2 在启动类中添加 @ServletComponentScan 注解

• 扫描WebFilter注解，让该注解生效
• 

package com.it.heima.springboot06filter;

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

@SpringBootApplication
@ServletComponentScan("com.it.heima.springboot06filter.filter")
public class Springboot06FilterApplication {
    public static void main(String[] args) {
        SpringApplication.run(Springboot06FilterApplication.class, args);
    }

}

测试结果

package com.it.heima.springboot06filter.controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
@RequestMapping("user")
public class UserController {
    @RequestMapping("test")
    public String test(){
        System.out.println("正在执行test方法");
        return "test";
    }
}

二，创建过滤器配置类，注册过滤器

1 创建过滤器类（不添加WebFilter注解）

package com.it.heima.springboot06filter.filter;

import jakarta.servlet.*;

import java.io.IOException;

public class UserFilter implements Filter {
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
        System.out.println("正在初始化~~~~~~");
    }

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        System.out.println("是否满足条件");
        System.out.println("如满足条件放行~~~~~~~~");
        filterChain.doFilter(servletRequest,servletResponse);
    }

    @Override
    public void destroy() {
        System.out.println("正在销毁~~~~~~");

    }
}

2创建配置类， 注册过滤器类

package com.it.heima.springboot06filter.config;

import com.it.heima.springboot06filter.filter.UserFilter;
import org.springframework.boot.web.servlet.FilterRegistrationBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
@Configuration
public class FilterConfig implements WebMvcConfigurer {
    @Bean
    public FilterRegistrationBean filterRegistrationBean(){
        // 创建过滤器注册对象
        FilterRegistrationBean filterRegistrationBean = new FilterRegistrationBean();
        // 把过滤器注入到过滤器注册对象中
        filterRegistrationBean.setFilter(new UserFilter());
        // 设置过滤器拦截的请求
        filterRegistrationBean.addUrlPatterns("/*");
        return filterRegistrationBean;

    }
}

测试结果