跨域及解决跨域

什么是跨域

前端与后端不在同一个域名下：

解决

import jakarta.servlet.*;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;
import org.springframework.stereotype.Component;import java.io.IOException;@Component
public class CorsFilter implements Filter {//这里具体设置什么需要根据实际情况private static final String ALLOWED_HEADERS = "X-Requested-With, Content-Type, Authorization, token";@Overridepublic void init(FilterConfig filterConfig) throws ServletException {}@Overridepublic void doFilter(ServletRequest req, ServletResponse res, FilterChain chain) throws IOException, ServletException {HttpServletResponse response = (HttpServletResponse) res;HttpServletRequest request = (HttpServletRequest) req;// 设置CORS头response.setHeader("Access-Control-Allow-Origin", "*");response.setHeader("Access-Control-Allow-Methods", "GET, POST, PUT, DELETE, OPTIONS");response.setHeader("Access-Control-Max-Age", "3600");response.setHeader("Access-Control-Allow-Headers", ALLOWED_HEADERS);if ("OPTIONS".equalsIgnoreCase(request.getMethod())) {response.setStatus(HttpServletResponse.SC_OK);} else {chain.doFilter(req, res);}}@Overridepublic void destroy() {}
}