前端请求报错：

jquery.js?eedf:10254 Access to XMLHttpRequest at 'http://192.168.186.201:7777/insure/insure/saveInsureHGDM' from origin 'http://localhost:8080' has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource.

解决方案：
在配置文件当中添加一个类

@Configuration  
public class CorsConfig extends WebMvcConfigurerAdapter {
    private CorsConfiguration buildConfig() {  
        CorsConfiguration corsConfiguration = new CorsConfiguration();  
        corsConfiguration.addAllowedOrigin("*"); // 1允许任何域名使用
        corsConfiguration.addAllowedHeader("*"); // 2允许任何头
        corsConfiguration.addAllowedMethod("*"); // 3允许任何方法（post、get等） 
        return corsConfiguration;  
    }  
  
    @Bean  
    public CorsFilter corsFilter() {  
        UrlBasedCorsConfigurationSource source = new UrlBasedCorsConfigurationSource();  
        source.registerCorsConfiguration("/**", buildConfig()); // 4  
        return new CorsFilter(source);  
    }

    @Override
    public void addCorsMappings(CorsRegistry registry) {
        registry.addMapping("/**");
    }
}

该方案适用于大部分跨域问题

直到我遇到权限与跨域冲突，导致了我的cors跨域失效！

然后再次报出上面的错误。

解决方案
https://segmentfault.com/a/1190000010348077

解决方案二：
core里添加一个拦截器类

@WebFilter(urlPatterns = "/*", filterName = "CorsFilter")
public class CorsFilter implements Filter {
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {

    }

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        HttpServletResponse response = (HttpServletResponse) servletResponse;
        HttpServletRequest request = (HttpServletRequest)servletRequest;

        String origin = request.getHeader("Origin");
        response.setHeader("Access-Control-Allow-Origin", origin);
        response.setHeader("Access-Control-Allow-Methods", "POST, GET, OPTIONS, DELETE");
        response.setHeader("Access-Control-Max-Age", "3600");
        response.setHeader("Access-Control-Allow-Headers", "x-requested-with,content-type,token");
        response.setHeader("Access-Control-Allow-Credentials", "true");
        String method = request.getMethod();
        if(method.equalsIgnoreCase("OPTIONS")){
            servletResponse.getOutputStream().write("Success".getBytes("utf-8"));
        }else{
            filterChain.doFilter(servletRequest, servletResponse);
        }
    }

    @Override
    public void destroy() {

    }
}

然后在springboot的启动类加一个注解

@ServletComponentScan("")

括号里是拦截器的路径