请描述一下如何在SpringBoot项目中实现跨域请求（CORS）的处理?

import org.springframework.context.annotation.Bean;
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 WebConfig implements WebMvcConfigurer {

    @Override
    public void addCorsMappings(CorsRegistry registry) {
        registry.addMapping("/**")           // 允许所有路径
                .allowedOrigins("http://localhost:3000")  // 允许的源地址
                .allowedMethods("GET", "POST", "PUT", "DELETE") // 允许的HTTP方法
                .allowedHeaders("*")        // 允许的请求头
                .allowCredentials(true)     // 是否允许带上认证信息
                .maxAge(3600);              // 预检请求缓存时间
    }
}

import org.springframework.web.bind.annotation.CrossOrigin;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class MyController {

    @CrossOrigin(origins = "http://localhost:3000")
    @GetMapping("/api/data")
    public String getData() {
        return "This is data from backend";
    }
}

@CrossOrigin
@GetMapping("/api/data")
public String getData() {
    return "This is data from backend";
}

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.security.config.annotation.web.builders.HttpSecurity;
import org.springframework.security.config.annotation.web.configuration.EnableWebSecurity;
import org.springframework.security.config.annotation.web.configuration.WebSecurityConfigurerAdapter;

@Configuration
@EnableWebSecurity
public class SecurityConfig extends WebSecurityConfigurerAdapter {

    @Override
    protected void configure(HttpSecurity http) throws Exception {
        http.cors().and()
            .authorizeRequests()
            .anyRequest().authenticated();
    }

    @Bean
    public CorsConfigurationSource corsConfigurationSource() {
        CorsConfiguration configuration = new CorsConfiguration();
        configuration.addAllowedOrigin("http://localhost:3000");
        configuration.addAllowedMethod("*");
        configuration.addAllowedHeader("*");
        configuration.setAllowCredentials(true);
        UrlBasedCorsConfigurationSource source = new UrlBasedCorsConfigurationSource();
        source.registerCorsConfiguration("/**", configuration);
        return source;
    }
}