spring自定义注解

使用spring自定义注解实现权限访问

1. 首先定义注解类
2. 使用拦截器实现注解功能
3. 配置拦截器
4. 在controller层使用注解

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 Permission {
    /**
     * 资源key
     * */
    String value();
}

import com.annotation.demo.annotation.Permission;
import org.springframework.web.method.HandlerMethod;
import org.springframework.web.servlet.HandlerInterceptor;

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

public class PermissionInterceptor implements HandlerInterceptor {


    /**
     * 处理器处理之前调用
     */
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response,
                             Object handler) {
        HandlerMethod handlerMethod = (HandlerMethod) handler;

        //在方法上寻找注解
        Permission permission = handlerMethod.getMethodAnnotation(Permission.class);
        if (permission == null) {
            //在类上寻找注解
            permission = handlerMethod.getBeanType().getAnnotation(Permission.class);
        }

        //如果没有添加权限注解则直接跳过允许访问
        if (permission == null) {
            return true;
        }

        //获取注解中的值
        String value = permission.value();

        if ("admin".equals(value)) {
            return true;
        }

        return false;
    }


}

import com.annotation.demo.interceptor.PermissionInterceptor;
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 InterceptorConfig implements WebMvcConfigurer {

    /**
     * 注册自定义拦截器
     */
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(new PermissionInterceptor()).addPathPatterns("/api/**");
    }
}

package com.annotation.demo.controller;

import com.annotation.demo.annotation.Permission;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

/**
 * @author : spiderman
 * @version : 1.0
 * @FileName : com.annotation.demo
 * @Description :
 * @Create Date : 2022/1/5 00:24
 **/
@RestController
public class TestController {

    /**
     * 权限为admin才能访问
     * @return
     */
    @RequestMapping("/api/test")
    @Permission(value = "admin")
    public String test() {
        return "hello world";
    }

    /**
     * 权限为test2才能访问
     * @return
     */
    @RequestMapping("/api/test2")
    @Permission(value = "test2")
    public String test2() {
        return "hello world";
    }

}