springBoot自定义注解

我就是我 2023-10-11 14:44 13阅读 0赞

## 1.自定义注解一般用拦截或者在处理业务逻辑之前进行的操作，比如我们需要在每次处理前端发出的请求时进行认证token的操作，这时就需要自定义注解 ##

## 2.自定义注解的实现 ##

### 2.1创建自定义注解类 ###

下面以拦截token的注解为例

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 UserLoginToken {
        
        boolean required() default true;
    }

这时一个自定义注解就已经实现，下面创建一个自定义注解的拦截操作

### 2.2 创建拦截器 ###

import com.personal.api.po.Constants;
    import com.personal.indentity.annoation.PassToken;
    import com.personal.indentity.annoation.UserEffective;
    import com.personal.indentity.annoation.UserLoginToken;
    import com.personal.indentity.service.UserService;
    import com.personal.indentity.utils.TokenUtils;
    import org.slf4j.Logger;
    import org.slf4j.LoggerFactory;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.stereotype.Controller;
    import org.springframework.web.method.HandlerMethod;
    import org.springframework.web.servlet.HandlerInterceptor;
    import org.springframework.web.servlet.ModelAndView;
    import redis.clients.jedis.Jedis;
    
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    import java.lang.reflect.Method;
    
    @Controller
    public class AuthenticationInterceptor implements HandlerInterceptor {
        
        @Override
        public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        
            // 如果不是映射到方法直接通过
            if (!(handler instanceof HandlerMethod)) {
        
                return true;
            }
            HandlerMethod handlerMethod = (HandlerMethod) handler;
            Method method = handlerMethod.getMethod();
            /**检查有没有需要用户权限的注解**/
            if (method.isAnnotationPresent(UserLoginToken.class)) {
        
                UserLoginToken userLoginToken = method.getAnnotation(UserLoginToken.class);
                if (userLoginToken.required()) {
        
                    // 执行认证
                    if (token == null) {
        
                        throw new RuntimeException("无token，请重新登录");
                    }
                    //校验token有效性
                    Boolean verify = false;
                    try {
        
                        verify = TokenUtils.verifyToken(token);
                    } catch (Exception e) {
        
                        verify = false;
                        throw new RuntimeException("无效token");
                    }
                    if(!verify){
        
                        throw new RuntimeException("token校验失败");
                    }
                    return true;
                }
            }
            return true;
        }
        @Override
        public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
        
    
        }
        @Override
        public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
        
    
        }
    }

### 2.3如何使用这个注解 ###

我们自定完成一个注解之后和spring内置注解一样，只需在controller中添加对应的注解即可

/***
         * 判断token是否有效
         * @date 2019/06/14
         * @return String 返回类型
         */
        @ResponseBody
        @UserLoginToken
        @RequestMapping(value = "/judgeToken", method = RequestMethod.GET)
        public String getMessage(HttpServletResponse response, HttpServletRequest request) {
        
            return "校验token";
        }

至此一个完整的自定义注解就已经实现了