Springboot处理跨域的实现方式(附Demo)

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

@RestController
@RequestMapping("/api")
public class MyController {

    @CrossOrigin(origins = "http://example.com")
    @GetMapping("/data")
    public String getData() {
        return "Data from server";
    }
}

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;

/**
 * 配置类，用于全局设置 CORS（跨域资源共享）配置
 */
@Configuration
public class WebConfig implements WebMvcConfigurer {

    /**
     * 配置跨域请求的映射规则
     * 
     * @param registry 用于注册 CORS 配置的注册表
     */
    @Override
    public void addCorsMappings(CorsRegistry registry) {
        // 添加跨域映射规则
        registry.addMapping("/**")  // 允许所有路径的跨域请求
                .allowedOrigins("http://example.com")  // 允许来自 http://example.com 的跨域请求
                .allowedMethods("GET", "POST", "PUT", "DELETE")  // 允许的请求方法
                .allowedHeaders("*")  // 允许所有请求头
                .allowCredentials(true);  // 允许携带凭证（如 Cookies）
    }
}

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 CustomCorsConfig implements WebMvcConfigurer {

    @Bean
    public CorsConfigurationSource corsConfigurationSource() {
        CorsConfiguration configuration = new CorsConfiguration();
        configuration.setAllowedOrigins(Arrays.asList("http://example.com"));
        configuration.setAllowedMethods(Arrays.asList("GET", "POST", "PUT", "DELETE"));
        configuration.setAllowedHeaders(Arrays.asList("*"));
        configuration.setAllowCredentials(true);

        UrlBasedCorsConfigurationSource source = new UrlBasedCorsConfigurationSource();
        source.registerCorsConfiguration("/**", configuration);

        return source;
    }
}

import org.springframework.boot.autoconfigure.AutoConfiguration;
import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
import org.springframework.boot.web.servlet.FilterRegistrationBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.filter.CorsFilter;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
import org.springframework.web.cors.CorsConfiguration;
import org.springframework.web.cors.UrlBasedCorsConfigurationSource;

@Configuration
@AutoConfiguration
@EnableConfigurationProperties(WebProperties.class)
public class WebAutoConfiguration implements WebMvcConfigurer {

    /**
     * 创建一个 CorsFilter 过滤器的 Bean，配置跨域设置
     *
     * @return 配置了跨域设置的 FilterRegistrationBean
     */
    @Bean
    public FilterRegistrationBean<CorsFilter> corsFilterBean() {
        // 创建 CorsConfiguration 对象
        CorsConfiguration config = new CorsConfiguration();
        config.setAllowCredentials(true);  // 允许携带凭证（如 Cookies）
        config.addAllowedOriginPattern("*"); // 允许所有来源的请求（注意：生产环境中通常不建议使用 *，应具体配置允许的域）
        config.addAllowedHeader("*"); // 允许所有请求头
        config.addAllowedMethod("*"); // 允许所有 HTTP 方法（GET, POST, PUT, DELETE 等）

        // 创建 UrlBasedCorsConfigurationSource 对象
        UrlBasedCorsConfigurationSource source = new UrlBasedCorsConfigurationSource();
        source.registerCorsConfiguration("/**", config); // 对所有路径配置跨域设置

        // 创建并返回一个 FilterRegistrationBean 实例，注册 CorsFilter
        return createFilterBean(new CorsFilter(source), Integer.MIN_VALUE);
    }

    /**
     * 创建 DemoFilter Bean，演示模式
     * 
     * @return 配置了 DemoFilter 的 FilterRegistrationBean
     */
    @Bean
    @ConditionalOnProperty(value = "demo", havingValue = "true")
    public FilterRegistrationBean<DemoFilter> demoFilter() {
        // 创建并返回一个 FilterRegistrationBean 实例，注册 DemoFilter
        return createFilterBean(new DemoFilter(), Integer.MIN_VALUE);
    }

    /**
     * 创建 FilterRegistrationBean 实例的通用方法
     * 
     * @param filter 需要注册的过滤器实例
     * @param order  过滤器的执行顺序
     * @return 配置了过滤器的 FilterRegistrationBean 实例
     */
    public static <T extends Filter> FilterRegistrationBean<T> createFilterBean(T filter, Integer order) {
        FilterRegistrationBean<T> bean = new FilterRegistrationBean<>(filter);
        bean.setOrder(order);  // 设置过滤器的顺序
        return bean;
    }
}