SpringMVC、SpringBoot实现跨域访问

　　由于很多地方都需要使用到跨域访问（前后端分离开发、集群部署、微服务间的调用等），但是由于传统的ajax通过JSONP的局限性，在这里将总结后端SpringMVC、SpringBoot实现跨域访问的方法。

　　一、通过过滤器实现

import org.springframework.context.annotation.Configuration;
import javax.servlet.*;
import javax.servlet.annotation.WebFilter;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.Arrays;
import java.util.Collection;
import java.util.HashSet;
import java.util.Set;

/**
 * Author: johnson
 * DATE: 2017-07-03.11:25
 * description:
 * version:
 */
@Configuration
@WebFilter(filterName = "UrlFilter",urlPatterns = "/*")
public class UrlFilter implements Filter {
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {

    }

    public void doFilter(ServletRequest req, ServletResponse resp, FilterChain chain) throws IOException, ServletException {
        HttpServletResponse response = (HttpServletResponse) resp;
        HttpServletRequest request = (HttpServletRequest) req;
//        Cookie[] cookies = request.getCookies();
//        if(cookies != null && cookies.length > 0){
//            for(Cookie cookie : cookies) {
//                if(cookie != null)
//                cookie.setPath("/");
//            }
//
//        }
        
        //headers中配置了允许跨域访问的ip和端口
        String[] headers = {"http://192.168.1.25:39638","http://192.168.1.25:80","http://192.168.1.25:10103","http://192.168.1.25:10104","http://192.168.1.25:8081","http://192.168.1.15:8080"};
        Set<String> allowedOrigins= new HashSet<String>(Arrays.asList(headers));
        String originHeader=request.getHeader("Origin");
        Collection<String> headerNames = response.getHeaderNames();
        if (allowedOrigins.contains(originHeader)) {
            response.setHeader("Access-Control-Allow-Origin", originHeader); //解决跨域访问报错http://192.168.1.14:8081
            response.setHeader("Access-Control-Allow-Methods", "POST, PUT, GET, OPTIONS, DELETE");
            response.setHeader("Access-Control-Allow-Credentials", "true");
            response.setHeader("Access-Control-Max-Age", "3600"); //设置过期时间
            response.setHeader("Access-Control-Allow-Headers", "Origin, X-Requested-With, Content-Type, Accept, client_id, uuid, Authorization");
            response.setHeader("Cache-Control", "no-cache, no-store, must-revalidate"); // 支持HTTP 1.1.
            response.setHeader("Pragma", "no-cache"); // 支持HTTP 1.0. response.setHeader("Expires", "0");
            String method = request.getMethod();
            String requestURI = request.getRequestURI();
            StringBuffer requestURL = request.getRequestURL();
        }

        chain.doFilter(req, resp);

    }

    @Override
    public void destroy() {

    }
}

　　二、通过CORS解决跨域问题

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.CorsRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;

@Configuration
public class CorsConfiguration {

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

　　上面方案中，第一种可以做到只允许特定的计算机进行跨域访问，第二种则没有做过多的操作，支持所有的跨域访问,如果想进一步限制方法等，代码如下:

registry.addMapping("/**")
        .allowedMethods(HttpMethod.GET.name(), HttpMethod.POST.name(), HttpMethod.PUT.name(),
                HttpMethod.PATCH.name(), HttpMethod.DELETE.name(),HttpMethod.OPTIONS.name()) // 允许访问方法类型
        .allowCredentials(true)
        .maxAge(3600) .allowedHeaders("Content-Type", "X-Requested-With", "accept", "Origin", "Access-Control-Request-Method",
        "Access-Control-Request-Headers","Access-Control-Allow-Headers","token")
        .exposedHeaders("Access-Control-Allow-Origin", "Access-Control-Allow-Credentials","Access-Control-Request-Headers","Access-Control-Allow-Headers","token");

　　

　　参考资料:https://blog.csdn.net/qq_27092581/article/details/92641342

　　　　　　 https://segmentfault.com/a/1190000012469713