spring boot——请求与参数校验——重要概念——拦截器

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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拦截器示例：

控制器：

package org.example.controller;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.ResponseBody;


@Controller
public class HelloController
{
    //  http://localhost:8080/hello
    @ResponseBody
    @RequestMapping("/hello")
    public String hello()
    {

        return "Hello World!____________china";
    }
    
    //    http://localhost:8080/123
    @ResponseBody
    @RequestMapping("/123")
    public String home123()
    {
        return "中国您好";
    }



    //   http://localhost:8080/1234
    @RequestMapping(value = "/1234",method = RequestMethod.GET)
    @ResponseBody
    public String home1234()
    {
        return "中国您好_123456";
    }
}

 

 

 

 

 

 

 

 

 

 

 

 

定义一个拦截器：

package org.example.controller.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 UseInterceptor implements HandlerInterceptor {

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {

        if ("b".equals(request.getParameter("a"))) {

            System.out.println("请求不成功");

            return false;
        } else {

            System.out.println("该方法在控制器处理请求方法前执行，其返回值表示是否中断后续操作，返回 true 表示继续向下执行，返回 false 表示中断后续操作。");
            //放行
            return true;
        }
    }


    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {

        System.out.println("该方法在控制器处理请求方法调用之后、解析视图之前执行，可以通过此方法对请求域中的模型和视图做进一步修改。");


    }



}

 

 

 

 

 

 

 

 

 

注册拦截器：

package org.example.config;

import org.example.controller.Interceptor.UseInterceptor;
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 MyMvcConfig implements WebMvcConfigurer {

    @Override
    public void addInterceptors(InterceptorRegistry registry) {


        System.out.println("注册拦截器");

        registry.addInterceptor(new UseInterceptor()).addPathPatterns("/**") //拦截所有请求，包括静态资源文件
                .excludePathPatterns("/", "/login", "/index.html", "/user/login", "/css/**", "/images/**", "/js/**", "/fonts/**"); //放行登录页，登陆操作，静态资源
    }
}

 

 

 

 

 

 

 

请求：http://localhost:8080/hello?a=b

 

 

 

 

 

 

 

 

 

 

 

请求：http://localhost:8080/hello?a=c

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

PS: