springBoot自定义参数注解

前置条件：新建一个springboot项目

1.新建一个标记注解@Auth

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

/**
 * @author wangfan
 */
@Target(ElementType.PARAMETER)
@Retention(RetentionPolicy.RUNTIME)
public @interface Auth {
}

2.新建一个处理器继承HandlerMethodArgumentResolver

import com.example.anno.Auth;
import com.example.po.UserPO;
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.method.support.HandlerMethodArgumentResolver;
import org.springframework.web.method.support.ModelAndViewContainer;
/**
 * @author wangfan
 */
@Component
public class UserParamResolver implements HandlerMethodArgumentResolver {
    @Override
    public boolean supportsParameter(MethodParameter methodParameter) {
        //判断方法参数是不是UserPO，判断参数是否带有Auth注解
        return methodParameter.getParameterType().isAssignableFrom(UserPO.class) && methodParameter.hasParameterAnnotation(Auth.class);
    }

    @Override
    public Object resolveArgument(MethodParameter methodParameter, ModelAndViewContainer modelAndViewContainer, NativeWebRequest nativeWebRequest, WebDataBinderFactory webDataBinderFactory) throws Exception {
        //模拟从Redis/security/session里获取信息
        UserPO user = new UserPO();
        user.setId(1L);
        user.setName("wangfan");
        return user;
    }
}

3.将处理器添加到Mvc

package com.example.config;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.method.support.HandlerMethodArgumentResolver;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;

import javax.annotation.Resource;
import java.util.List;

/**
 * @author wangfan
 */
@Configuration
public class MyMvcConfig extends WebMvcConfigurerAdapter{

    @Resource
    private UserParamResolver userParamResolver;
    @Override
    public void addArgumentResolvers(List<HandlerMethodArgumentResolver> argumentResolvers) {
        super.addArgumentResolvers(argumentResolvers);
        argumentResolvers.add(userParamResolver);
    }
}

4.写个接口测试

import com.example.anno.Auth;
import com.example.po.UserPO;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
/**
 * @author wangfan
 */
@RestController
public class TestController {
    @GetMapping("/testAuth")
    public UserPO testAuth(@Auth UserPO user){
        return user;
    }
}