后端：

package com.example.mybatisplustest.config;

import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.CorsRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;

@Configuration
public class Cors implements WebMvcConfigurer {
    @Override
    public void addCorsMappings(CorsRegistry registry) {
        registry.addMapping("/**")
                .allowedOrigins("*")
                .allowedMethods("GET", "POST", "PUT", "OPTIONS", "DELETE", "PATCH")
                .allowedHeaders("*")
                .allowCredentials(true).maxAge(3600);
    }
}

package com.example.mybatisplustest.config;

import org.springframework.context.annotation.Configuration;

import javax.servlet.*;
import javax.servlet.an