SpringBoot跨域问题

 一、适用场景：

HTTPS协议是由SSL+HTTP协议构建的可进行加密传输、身份认证的网络协议，要比http协议安全。

当我们对外提供服务是需要通过域名访问我们的服务，获取数据，在内网中我们可以通过http访问，前端访问后端也可以通过http,这时候的协议是一致的不会存在跨域问题。
 

当前端提供的是https 后端提供的确实http，就会出现跨域问题。
我们一般对外的服务都是通过https的，所以需要后端解决跨域访问问题。前端提供出去的域名一定是HTTPS协议。

二、出现问题：

访问接口：
strict-origin-when-cross-origin

访问服务：
When allowCredentials is true, allowedOrigins cannot contain the special value "*"since that cannot be set on the "Access-Control-Allow-Origin" response header. To allow credentials to a set of origins, list them explicitly or consider using "allowedOriginPatterns" instead.

意思是：当allowCredentials为true时，allowingOrigins不能包含特殊值“ *”，因为无法在“ Access-Control-Allow-Origin”响应标头上设置。要允许凭据具有一组来源，请明确列出它们或考虑改用“ allowedOriginPatterns”。
 

三、解决-两个类建议和启动类同级目录

@SpringBootConfiguration
public class MyWebConfigurer implements WebMvcConfigurer {

    @Override
    public void addCorsMappings(CorsRegistry corsRegistry) {
        /**
         * 所有请求都允许跨域，使用这种配置就不需要
         * 在interceptor中配置header了
         */
        corsRegistry.addMapping("/**")
                .allowCredentials(true)
                .allowedOriginPatterns("*")
                .allowedMethods("POST", "GET", "PUT", "OPTIONS", "DELETE")
                .allowedHeaders("*")
                .maxAge(3600);
    }
}

public class ProcessInterceptor implements HandlerInterceptor {

    @Override
    public boolean preHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o) throws Exception {
        httpServletResponse.setHeader("Access-Control-Allow-Origin", "*");
        httpServletResponse.setHeader("Access-Control-Allow-Headers", "Content-Type,Content-Length, Authorization, Accept,X-Requested-With");
        httpServletResponse.setHeader("Access-Control-Allow-Methods", "PUT,POST,GET,DELETE,OPTIONS");
        httpServletResponse.setHeader("X-Powered-By", "Jetty");

        String method = httpServletRequest.getMethod();
        if (method.equals("OPTIONS")) {
            httpServletResponse.setStatus(200);
            return false;
        }
        System.out.println(method);
        return true;
    }

    @Override
    public void postHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, ModelAndView modelAndView) throws Exception {
    }

    @Override
    public void afterCompletion(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, Exception e) throws Exception {
    }
}

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