SpringBoot 过滤器与拦截器实例演示

   springboot中的过滤器拦截器操作与springmvc中的几乎一样所以这里也不过多介绍了，下面举两个简单的栗子演示一下

1、过滤器        

1 创建过滤器类loginfilter,实现servlet包下的filter接口（包不要导错），加入注解webfilter

package com.example.filter;
 
import javax.servlet.*;
import javax.servlet.annotation.webfilter;
import javax.servlet.http.httpservletrequest;
import javax.servlet.http.httpservletresponse;
import java.io.ioexception;
 
@webfilter(urlpatterns = "/filter/*")
public class loginfilter implements filter {
    @override
    public void init(filterconfig filterconfig) throws servletexception {
        system.out.println("初始化拦截器");
    }
 
    @override
    public void dofilter(servletrequest servletrequest, servletresponse servletresponse, filterchain filterchain) throws ioexception, servletexception {
        system.out.println("loginfilter");
        httpservletrequest request = (httpservletrequest)servletrequest;
        httpservletresponse response = (httpservletresponse)servletresponse;
        //放行
        filterchain.dofilter(request,response);
    }
 
    @override
    public void destroy() {
        system.out.println("拦截器销毁");
    }
}

     2 创建测试类logincotroller

package com.example.controller;
 
import org.springframework.web.bind.annotation.requestmapping;
import org.springframework.web.bind.annotation.restcontroller;
 
@restcontroller
@requestmapping("/filter")
public class filtercontroller {
 
    @requestmapping("/login")
    public string login(){
        system.out.println("登录");
        return "login";
    }
 
}

      3 在启动类上加注解

package com.example;
 
import org.springframework.boot.springapplication;
import org.springframework.boot.autoconfigure.springbootapplication;
import org.springframework.boot.web.servlet.servletcomponentscan;
 
@springbootapplication
@servletcomponentscan
//servlet、filter、listener可以直接通过@webservlet、@webfilter、@weblistener注解自动注册
public class demoapplication {
 
    public static void main(string[] args) {
        springapplication.run(demoapplication.class, args);
    }
 
}

  4 启动测试，启动的时候可以看到filter调用init方法初始化

 接着访问可以看到页面输出

 控制台打印出拦截器中的语句

2、拦截器        

1 创建自定义拦截器

package com.example.interceptor;
 
import org.springframework.web.servlet.handlerinterceptor;
import org.springframework.web.servlet.modelandview;
 
import javax.servlet.http.httpservletrequest;
import javax.servlet.http.httpservletresponse;
 
public class myinterceptor implements handlerinterceptor {
   //进入controller方法之前调用的
    @override
    public boolean prehandle(httpservletrequest request, httpservletresponse response, object handler) throws exception {
        system.out.println("prehandle");
        return true;//true表示放行 false表示不放行
    }
    //调用完controller之后，视图渲染层之前
    @override
    public void posthandle(httpservletrequest request, httpservletresponse response, object handler, modelandview modelandview) throws exception {
        system.out.println("posthandle");
    }
    //页面跳转之后，整个流程执行之后，一般用于资源的清理
    @override
    public void aftercompletion(httpservletrequest request, httpservletresponse response, object handler, exception ex) throws exception {
        system.out.println("aftercompletion");
    }
}

      2 创建拦截器配置类，注意要加上配置类的注解

package com.example.config;
 
import com.example.interceptor.myinterceptor;
import org.springframework.context.annotation.configuration;
import org.springframework.web.servlet.config.annotation.interceptorregistry;
import org.springframework.web.servlet.config.annotation.webmvcconfigurer;
 
@configuration
public class myinterceptorconfig implements webmvcconfigurer {
 
    @override
    public void addinterceptors(interceptorregistry registry) {
        //设置拦截器并指定拦截路径
        registry.addinterceptor(new myinterceptor()).addpathpatterns("/interceptor/*");
        //registry.addinterceptor(new myinterceptor()).addpathpatterns("/**");//拦截所有
        //registry.addinterceptor(new myinterceptor()).addpathpatterns("/**").excludepathpatterns("/test");//指定不拦截
 
        //添加自定义拦截器
        webmvcconfigurer.super.addinterceptors(registry);
    }
}

        3 创建logincontroller测试类

package com.example.controller;
 
import org.springframework.web.bind.annotation.requestmapping;
import org.springframework.web.bind.annotation.restcontroller;
 
@restcontroller
@requestmapping("/interceptor")
public class interceptorcontroller {
    @requestmapping("login")
    public string login(){
        system.out.println("interceptor-login");
        return "login";
    }
}

      4 运行访问，查看效果

控制台输出如下

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