springBoot 跨域处理

首先喝水不忘挖井人，博客参考：https://www.cnblogs.com/nananana/p/8492185.html

方式一：新增一个configration类 或 在Application中加入CorsFilter和CorsConfiguration方法

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.cors.CorsConfiguration;
import org.springframework.web.cors.UrlBasedCorsConfigurationSource;
import org.springframework.web.filter.CorsFilter;

@Configuration
@SpringBootApplication
public class FileProApplication {

    public static void main(String[] args) {
        SpringApplication.run(FileProApplication.class, args);
    }

    private CorsConfiguration buildConfig() {
        CorsConfiguration corsConfiguration = new CorsConfiguration();
        corsConfiguration.addAllowedOrigin("*"); // 1允许任何域名使用
        corsConfiguration.addAllowedHeader("*"); // 2允许任何头
        corsConfiguration.addAllowedMethod("*"); // 3允许任何方法（post、get等）
        return corsConfiguration;
    }  

    @Bean
    public CorsFilter corsFilter() {
        UrlBasedCorsConfigurationSource source = new UrlBasedCorsConfigurationSource();
        source.registerCorsConfiguration("/**", buildConfig()); // 4
        return new CorsFilter(source);
    }  

}

但是我在和前端人员调试的过程中，发现此方法，给pc端有用，但是微信开发，还是会报跨域问题，所以我用了第二种方法，并且加以改善：

我把接收到的跨域请求头部，重新转发回去。这样就解决了微信端的跨域问题。

方式二：使用过滤器方式，接收到头部，转发回去

import java.io.IOException;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.springframework.stereotype.Component;

@Component
public class CorsFilter implements Filter{

    @Override
    public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain)
            throws IOException, ServletException {
        HttpServletRequest request = (HttpServletRequest) req;
        String header = request.getHeader("Origin");
        HttpServletResponse response = (HttpServletResponse) res;
        if (header != null || !"".equals(header)) {//header不为空，就直接将拿到的转发回去
            response.setHeader("Access-Control-Allow-Origin", header);
        }else {
            response.setHeader("Access-Control-Allow-Origin", "*");
        }
        response.setHeader("Access-Control-Allow-Methods", "POST, GET, OPTIONS, DELETE,PUT");
        response.setHeader("Access-Control-Max-Age", "3600");
        response.setHeader("Access-Control-Allow-Headers", "*");
        response.setHeader("Access-Control-Allow-Credentials","true");
        chain.doFilter(req, res);
    }

    public void init(FilterConfig filterConfig) {}
    public void destroy() {} 

}