跨域问题，普通页面和iframe跨域

1.普通接口跨域

针对这个情况，可以写一个Java过滤器来解决问题

/**
 * 跨域过滤器
 */
public class OriginFilter implements Filter {
    public static final String PARAM_NAME_EXCLUSIONS = "exclusions";
    public static final String PARAM_NAME_INCLUSIONS = "inclusions";
    private Set<String> excludesPattern;
    private Set<String> includesPattern;
    protected String contextPath;
    protected PatternMatcher pathMatcher = new ServletPathMatcher();

    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
        String param = filterConfig.getInitParameter(PARAM_NAME_EXCLUSIONS);
        if (param != null && param.trim().length() != 0) {
            this.excludesPattern = new HashSet(Arrays.asList(param.split("\\s*,\\s*")));
        }
        String param_ = filterConfig.getInitParameter(PARAM_NAME_INCLUSIONS);
        if (param_ != null && param_.trim().length() != 0) {
            this.includesPattern = new HashSet(Arrays.asList(param_.split("\\s*,\\s*")));
        }
    }

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        HttpServletRequest httpRequest = (HttpServletRequest) servletRequest;
        HttpServletResponse httpResponse = (HttpServletResponse) servletResponse;

        //看着打印点参数（请求的头之类的）
        Logger log = LoggerFactory.getLogger(OriginFilter.class);
        Enumeration<String> head = httpRequest.getHeaderNames();
        String requestURI = this.getRequestURI(httpRequest);
        log.info(requestURI + ":>>>进了过滤器==============================");
        Enumeration enu = httpRequest.getParameterNames();
        Map map = new HashMap();
        while (enu.hasMoreElements()) {
            String paraName = (String) enu.nextElement();
            map.put(paraName, httpRequest.getParameter(paraName));
        }
        log.info(requestURI + ":" + String.valueOf(map));


        //跨域参数
        httpResponse.setHeader("Access-Control-Allow-Origin", "*");
        httpResponse.setHeader("Access-Control-Allow-Methods", "POST, GET, OPTIONS, DELETE");
        httpResponse.setHeader("Access-Control-Max-Age", "3600");
        httpResponse.setHeader("Access-Control-Allow-Headers", "x-requested-with,Encrypt,Access-token");
        //直接进行操作
        filterChain.doFilter(servletRequest, servletResponse);
    }

    @Override
    public void destroy() {

    }

    /**
     * 获取请求的url
     * @param request
     * @return
     */
    public String getRequestURI(HttpServletRequest request) {
        return request.getRequestURI();
    }
}

import javax.servlet.DispatcherType;
import java.util.ArrayList;
import java.util.List;

@Configuration
public class OrginFilterConfig {
    @Bean
    FilterRegistrationBean orginFilter() {
        FilterRegistrationBean filterReg = new FilterRegistrationBean(new OriginFilter());
        //优先级
        filterReg.setOrder(100);
        filterReg.setDispatcherTypes(DispatcherType.REQUEST);
        //匹配路径
        List<String> urlPatterns = new ArrayList<>();
//        urlPatterns.add("/*");
        //filterReg.addUrlPatterns("/*");
        //需要验证的url
        filterReg.addInitParameter("inclusions", "/**");
        //需要验证的url 中不进行token验证的url
        //filterReg.addInitParameter("exclusions", "/v1/user/login");
        return filterReg;
    }
}

这是我封好的一个简单的过滤器，拿去贴就能用

2.普通页面跨域

这个跨域一般使用场景是iframe吧，虽然现在在逐渐淘汰这东西，但是碰上不用还不行
父页面

	//获取iframe对象
    let frame = document.getElementById('对象id');
	//发请求
	let data={'name':'admin','psd':'123456'}
	frame.contentWindow.postMessage({response:user},'*');
	//接请求
	window.addEventListener('message',function(event){
		console.log(event.data.response);
	})

	//发请求
    window.parent.postMessage({response:'user'},'*');
	//接请求
	window.addEventListener('message',function(event){
        // event对象里很多传递的信息，可以逐条打印event看看
        //注意event.source是发送人的window对象
        user=event.data.response;
    })

3.跨域问题出现原因

1.不同域名

2.同域名不同端口

3.同域名不同协议