springboot2.0设置跨域没效果

1. 可能原因1：没有设置允许跨域

@Configuration
public class CrosConfig implements WebMvcConfigurer {
	@Override
    public void addCorsMappings(CorsRegistry registry) {
        registry.addMapping("/**")
                .allowedOrigins("*")
                .allowedMethods("*")
                .allowedHeaders("*")
                .allowCredentials(true)
                .exposedHeaders("")
                .maxAge(3600);
    }
}

2. 代码执行顺序，您可能在拦截器或者其他地方设置了跨域的代码，但是代码是先执行过滤器，所以会有跨域的问题
   所以需要在过滤器中设置跨域的问题

import org.springframework.core.Ordered;
import org.springframework.core.annotation.Order;
import org.springframework.http.HttpMethod;
import org.springframework.http.HttpStatus;
import org.springframework.stereotype.Component;

import javax.servlet.*;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

/**
 * @author Administrator
 */
@Component
@Order(Ordered.HIGHEST_PRECEDENCE)
public class SimpleCORSFilter implements Filter{

    @Override
    public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain) throws IOException, ServletException {

        HttpServletResponse response = (HttpServletResponse) res;
        HttpServletRequest request = (HttpServletRequest) req;
        response.setHeader("Access-Control-Allow-Origin", "*");
        response.setHeader("Access-Control-Allow-Methods", "POST, GET, OPTIONS, DELETE");
        response.setHeader("Access-Control-Max-Age", "3600");
        response.setHeader("Access-Control-Allow-Credentials", "true");
        response.setHeader("Access-Control-Allow-Headers", "*");
        if(request.getMethod().equals(HttpMethod.OPTIONS.name())){
            response.setStatus(HttpStatus.NO_CONTENT.value());
        }else{
            chain.doFilter(req, res);
        }
    }

    @Override
    public void init(FilterConfig filterConfig) {}

    @Override
    public void destroy() {}


}