在SpringBoot 2.x 中实现跨域的几种方式

1.注解实现局部跨域

在Controller方法或者类上使用

@CrossOrigin(origins = "http://localhost:8081",maxAge = 3600)

2.实现WebMvcConfigurer接口重写addCorsMappings实现全局跨域(推荐使用)

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

3.使用拦截器实现全局跨域（个人不建议使用，拦截器有很多副作用，比如静态资源被拦截，index.html欢迎页无法打开等问题，顶不住）

• 编写拦截器

@Component
public class CorsInterceptor implements HandlerInterceptor {
    
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) {

        response.setHeader("Access-Control-Allow-Origin", "*");
        response.setHeader("Access-Control-Allow-Credentials", "true");
        response.setHeader("Access-Control-Allow-Methods", "GET, HEAD, POST, PUT, PATCH, DELETE, OPTIONS");
        response.setHeader("Access-Control-Max-Age", "86400");
        response.setHeader("Access-Control-Allow-Headers", "*");

        // 如果是OPTIONS则结束请求
        if (HttpMethod.OPTIONS.toString().equals(request.getMethod())) {
            response.setStatus(HttpStatus.NO_CONTENT.value());
            return false;
        }
        return true;
    }
}

• 应用拦截器

@Configuration
public class RequestInterceptorConfig extends WebMvcConfigurationSupport {

    @Resource
    private CorsInterceptor corsInterceptor;

    @Override
    protected void addInterceptors(InterceptorRegistry registry) {
        // 注册跨域拦截器
        registry.addInterceptor(corsInterceptor).addPathPatterns("/api/**");
    }
}

4.参考资源

• 大牛博客