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

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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 {@Overridepublic void init(FilterConfig filterConfig) throws ServletException {System.out.println("正在初始化~~~~~~");}@Overridepublic 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);}@Overridepublic 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";}
}

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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 {@Overridepublic void init(FilterConfig filterConfig) throws ServletException {System.out.println("正在初始化~~~~~~");}@Overridepublic 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);}@Overridepublic 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 {@Beanpublic 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