请你谈谈：spring拦截器的应用（token校验）

java 复制代码

import cn.hutool.core.util.StrUtil;
import org.springframework.stereotype.Component;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

@Component
public class MyInterceptor implements HandlerInterceptor {
    private String TOKEN = "123456789.";

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        System.out.println("MyInterceptor preHandle： ");
        String token = request.getHeader("token");
        if (StrUtil.isBlank(token)) {
            response.getWriter().write("token is null");
            return false;
        }
        if (!TOKEN.equals(token)) {
            return false;
        }
        return true;
    }

    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
        System.out.println("MyInterceptor postHandle： ");
    }

    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
        System.out.println("MyInterceptor afterCompletion： ");
    }
}

java 复制代码

import org.springframework.beans.factory.annotation.Autowired;
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 WebmvcConfig implements WebMvcConfigurer {
    @Autowired
    private MyInterceptor myInterceptor;


    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(myInterceptor).addPathPatterns("/**");
    }
}

java 复制代码

import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class HelloController {
    @GetMapping("/hello")
    public String hello() {
        System.out.println("controller:");
        return "hello, zhaoshuai-lc";
    }
}

java 复制代码

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

@Target({ElementType.METHOD, ElementType.TYPE})
@Retention(RetentionPolicy.RUNTIME)
public @interface NoNeedToken {
}

java 复制代码

import cn.hutool.core.util.StrUtil;
import org.springframework.stereotype.Component;
import org.springframework.web.method.HandlerMethod;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

@Component
public class MyInterceptor implements HandlerInterceptor {
    private String TOKEN = "123456789.";

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        System.out.println("MyInterceptor preHandle： ");
        String token = request.getHeader("token");

        HandlerMethod handlerMethod = (HandlerMethod) handler;
        if (handlerMethod.getMethodAnnotation(NoNeedToken.class) != null ||
                handlerMethod.getBeanType().isAnnotationPresent(NoNeedToken.class)) {
            System.out.println("无需Token校验，放行...");
            return true;
        }

        if (StrUtil.isBlank(token)) {
            response.getWriter().write("token is null");
            return false;
        }
        if (!TOKEN.equals(token)) {
            return false;
        }
        return true;
    }

    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
        System.out.println("MyInterceptor postHandle： ");
    }

    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
        System.out.println("MyInterceptor afterCompletion： ");
    }
}

java 复制代码

@RestController
public class HelloController {
    @GetMapping("/hello")
    @NoNeedToken
    public String hello() {
        System.out.println("controller:");
        return "hello, zhaoshuai-lc";
    }
}