SpringBoot自定义注解示例分析——实现Token校验

当看到这个标题时，突然想到之前找工作时，室友被面试官问有没有自定义过注解，室友蒙了，回来告诉我们，结果我们一圈蒙了......

今天看到这个题目，不得不来补一下之前的旧账了，万一以后面试再被cue呢？

好了，话不多说。

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今天我们实现的自定义注解是一个Token验证。

一共分如下几步：

1.定义Token的注解，需要Token校验的接口，方法上加上此注解；

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.METHOD)
public @interface Token {
    boolean validate() default true;
}

2.定义LoginUser注解，此注解加在参数上，用在需要从token里获取的用户信息的地方；

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
@Target(ElementType.PARAMETER)
@Retention(RetentionPolicy.RUNTIME)
public @interface LoginUser {
}

3.权限的校验拦截器；

import com.example.demo.annotation.Token;
import com.example.demo.entity.User;
import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Component;
import org.springframework.web.method.HandlerMethod;
import org.springframework.web.servlet.handler.HandlerInterceptorAdapter;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
@Component
@Slf4j
public class AuthorizationInterceptor extends HandlerInterceptorAdapter {
    public static final String USER_KEY = "USER_ID";
    public static final String USER_INFO = "USER_INFO";
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        Token annotation;
        if(handler instanceof HandlerMethod) {
            annotation = ((HandlerMethod) handler).getMethodAnnotation(Token.class);
        }else{
            return true;
        }
        //没有声明需要权限,或者声明不验证权限
        if(annotation == null || annotation.validate() == false){
            return true;
        }
        //从header中获取token
        String token = request.getHeader("token");
        if(token == null){
            log.info("缺少token，拒绝访问");
            return false;
        }
        //查询token信息
//        User user = redisUtils.get(USER_INFO+token,User.class);
//        if(user == null){
//            log.info("token不正确，拒绝访问");
//            return false;
//        }
        //token校验通过，将用户信息放在request中，供需要用user信息的接口里从token取数据
        request.setAttribute(USER_KEY, "123456");
        User user=new User();
        user.setId(10000L);
        user.setUserName("2118724165@qq.com");
        user.setPhoneNumber("15702911111");
        user.setToken(token);
        request.setAttribute(USER_INFO, user);
        return true;
    }
}

4.写参数的解析器，将登陆用户对象注入到接口里；

import com.example.demo.annotation.LoginUser;
import com.example.demo.entity.User;
import com.example.demo.interceptor.AuthorizationInterceptor;
import org.springframework.core.MethodParameter;
import org.springframework.stereotype.Component;
import org.springframework.web.bind.support.WebDataBinderFactory;
import org.springframework.web.context.request.NativeWebRequest;
import org.springframework.web.context.request.RequestAttributes;
import org.springframework.web.method.support.HandlerMethodArgumentResolver;
import org.springframework.web.method.support.ModelAndViewContainer;
@Component
public class LoginUserHandlerMethodArgumentResolver implements HandlerMethodArgumentResolver
{
    @Override
    public boolean supportsParameter(MethodParameter methodParameter) {
        return methodParameter.getParameterType().isAssignableFrom(User.class)&&methodParameter.hasParameterAnnotation(LoginUser.class);
    }
    @Override
    public Object resolveArgument(MethodParameter methodParameter, ModelAndViewContainer modelAndViewContainer, NativeWebRequest nativeWebRequest, WebDataBinderFactory webDataBinderFactory) throws Exception {
        //获取登陆用户信息
        Object object = nativeWebRequest.getAttribute(AuthorizationInterceptor.USER_INFO, RequestAttributes.SCOPE_REQUEST);
        if(object == null){
            return null;
        }
        return (User)object;
    }
}

5.配置拦截器和参数解析器；

import com.example.demo.interceptor.AuthorizationInterceptor;
import com.example.demo.resolver.LoginUserHandlerMethodArgumentResolver;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.method.support.HandlerMethodArgumentResolver;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
import java.util.List;
 
@Configuration
public class WebMvcConfig implements WebMvcConfigurer {
    @Autowired
    private AuthorizationInterceptor authorizationInterceptor;
    @Autowired
    private LoginUserHandlerMethodArgumentResolver loginUserHandlerMethodArgumentResolver;
 
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(authorizationInterceptor).addPathPatterns("/api/**");
    }
 
    @Override
    public void addArgumentResolvers(List<HandlerMethodArgumentResolver> argumentResolvers) {
        argumentResolvers.add(loginUserHandlerMethodArgumentResolver);
    }
}

6.测试类；

import com.example.demo.annotation.LoginUser;
import com.example.demo.annotation.Token;
import com.example.demo.entity.User;
import lombok.extern.slf4j.Slf4j;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;
 
@RestController
@RequestMapping(value = "/api")
@Slf4j
public class TestController {
    @RequestMapping(value="/test",method = RequestMethod.POST)
    @Token
    public String test(@LoginUser User user){
        System.out.println("需要token才可以访问，呵呵……");
        log.info("user："+user.toString());
        return "test";
    }
    @RequestMapping(value="/noToken",method = RequestMethod.POST)
    public String noToken(){
        System.out.println("不用token就可以访问……");
        return "test";
    }
}

至此，自定义注解实现token校验就大功告成了。

参考及致谢：

1、SpringBoot自定义注解实现

2、Spring Boot项目中自定义注解的使用

Over.......