前后端分离遇到跨域问题 后端解决办法

先配置拦截器

import com.auth0.jwt.exceptions.AlgorithmMismatchException;
import com.auth0.jwt.exceptions.InvalidClaimException;
import com.auth0.jwt.exceptions.SignatureVerificationException;
import com.auth0.jwt.exceptions.TokenExpiredException;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.sxskz.chaoliu.util.TokenUtils;
import org.springframework.context.annotation.Configuration;
import org.springframework.stereotype.Component;
import org.springframework.web.servlet.HandlerInterceptor;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.util.HashMap;
import java.util.Map;

//@Component
@Configuration
public class AuthenticationInterceptor implements HandlerInterceptor {

    public boolean preHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object object) throws Exception {
        System.out.println("进入拦截器");
        httpServletResponse.setHeader("Access-Control-Allow-Origin", "*"); //解决跨域访问报错
        httpServletResponse.setHeader("Access-Control-Allow-Methods", "POST, PUT, GET, OPTIONS, DELETE");
        httpServletResponse.setHeader("Access-Control-Max-Age", "3600"); //设置过期时间
        httpServletResponse.setHeader("Access-Control-Allow-Headers", "Origin, X-Requested-With,Content-Type, Accept,token,client_id,identify, uuid, Authorization");
        httpServletResponse.setHeader("Cache-Control", "no-cache, no-store, must-revalidate"); // 支持HTTP 1.1.
        httpServletResponse.setHeader("Pragma", "no-cache"); // 支持HTTP 1.0. response.setHeader("Expires", "0");
        httpServletResponse.setHeader("Access-Control-Expose-Headers","X-forwared-port, X-forwarded-host");
        httpServletResponse.setHeader("Vary","Origin,Access-Control-Request-Method,Access-Control-Request-Headers");

        String token=httpServletRequest.getHeader("token");
        Map<String, Object> map = new HashMap<>();
        try {
            TokenUtils.verify(token);
            return true;
        } catch (SignatureVerificationException e) {
            e.printStackTrace();
            map.put("msg", "签名不一致");
            map.put("code",500);
        } catch (TokenExpiredException e) {
            e.printStackTrace();
            map.put("msg", "令牌过期");
            map.put("code",500);
        } catch (AlgorithmMismatchException e) {
            e.printStackTrace();
            map.put("msg", "算法不匹配");
            map.put("code",500);
        } catch (InvalidClaimException e) {
            e.printStackTrace();
            map.put("msg", "失效的payload");
            map.put("code",500);
        } catch (Exception e) {
            e.printStackTrace();
            map.put("msg", "token无效");
            map.put("code",500);
        }
        //根据自己所需选择所需的异常处理
        map.put("state", false);
        //响应到前台: 将map转为json
        String json = new ObjectMapper().writeValueAsString(map);
        httpServletResponse.setContentType("application/json;charset=UTF-8");
        httpServletResponse.getWriter().println(json);
        return false;

    }
}

再配置mvc

import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.CorsRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
/*
* 解决跨域
* */
@Configuration
public class WebConfig implements WebMvcConfigurer {
        @Override
        public void addCorsMappings(CorsRegistry registry) {
            // 设置允许跨域的路径
            registry.addMapping("/**")
                    // 设置允许跨域请求的域名
//                    .allowedOrigins("*")
                    .allowedOriginPatterns("*")

                    // 是否允许证书
                    .allowCredentials(true)
                    .allowedMethods("*")
                    .maxAge(3600);
        }

}