SpringBoot跨域问题解决

前端访问后台接口时，浏览器报错，跨域无法访问。

报错信息如下：

Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource.

经过一番百度之后，需要在控制器上添加处理跨域的注解，

注解添加后，再次访问接口，又有了新的报错：

Response to preflight request doesn't pass access control check: It does not have HTTP ok status.

根据资料显示，这个是因为浏览器预检请求失败，复杂请求会做预检请求，比如header中有自动以的属性等情况，当前的报错是指OPTION 请求失败，需要后端放行 OPTION 请求。

解决方法是定义个拦截器：

CorsInterceptor.java

package com.interceptor;

import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;
import org.springframework.http.HttpMethod;
import org.springframework.http.HttpStatus;
import org.springframework.stereotype.Component;
import org.springframework.web.servlet.HandlerInterceptor;

@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;
    }
}

然后将拦截器注册到全局拦截器中，使其生效。

WebConfig.java

package com.config;

import com.interceptor.CorsInterceptor;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;



@Configuration
public class WebConfig implements WebMvcConfigurer {

    @Autowired
    private CorsInterceptor corsInterceptor;

    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        //跨域拦截器需放在最上面
        registry.addInterceptor(corsInterceptor);

    }
}

再次访问接口，请求正常返回了