gateway网关、Springboot、Servlet跨域

一，gateway网关跨域

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.cors.CorsConfiguration;
import org.springframework.web.cors.reactive.CorsWebFilter;
import org.springframework.web.cors.reactive.UrlBasedCorsConfigurationSource;

@Configuration
public class AppConfig {
    @Bean
    public CorsWebFilter corsWebFilter() {
        CorsConfiguration config = new CorsConfiguration();
        config.setAllowCredentials(true);
        config.addAllowedOrigin("*");
        config.addAllowedHeader("*");
        config.addAllowedMethod("*");
        UrlBasedCorsConfigurationSource source = new UrlBasedCorsConfigurationSource();
        source.registerCorsConfiguration("/**", config);
        return new CorsWebFilter(source);
    }
}

二，springboot跨域

@Configuration
public class CorsConfig {

    @Bean
    public WebMvcConfigurer corsConfigurer() {
        return new WebMvcConfigurer() {
            @Override
            public void addCorsMappings(CorsRegistry registry) {
                registry.addMapping("/**")
                        .allowedOrigins("*")
                        .allowedMethods("*")
                        .allowedHeaders("*");
            }
        };
    }
}

三，servlet跨域

注意如果传了自定义header，需要覆盖doOptions方法，因为传自定义header后浏览器在发起请求前会发送一个options请求（chrome的开发工具看不到options请求，edge浏览器可以看到），不覆盖doOptions可以在edge的开发工具中看到options的响应码是403造成跨域失败：

import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class GetArchive3dData extends HttpServlet{
	
	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		doPost(request, response);
	}
	
	@Override
	public void doOptions(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException {
		doPost(request, response);
    }

	@Override
	public void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		response.setContentType("text/html");
		response.setCharacterEncoding("utf-8");
		// 允许所有域名的跨域请求
        response.setHeader("Access-Control-Allow-Origin", "*");
        // 允许特定的请求方法
        response.setHeader("Access-Control-Allow-Methods", "*");  
        // 允许特定的请求头
        response.setHeader("Access-Control-Allow-Headers", "*");
        
		PrintWriter out = response.getWriter();
		out.print("跨域请求返回的内容");
		out.flush();
		out.close();
	}

}