跨域

簡單理解就是跨域名 (ip+端口)
在 52liming.com 中向demo.com中發起Ajax請求, 出于安全考慮會進行攔截

參考：

• 瀏覽器的同源策略
• 什么是JS跨域訪問？
• 跨域資源共享 CORS 詳解
• Spring CORS 文檔
• Java CORS Filter Example

Maven中引入CORS Filter

• CORS Filter

Spring4.0之前 CORS

CORS 跨域資源共享 Cross-Origin Resource Sharing

實現攔截器方式, (因為這次項目中是用的的spring4.0.2, 所以記錄下來)

類似白名單

1. Filter 的實現類 CORSFilter.java

package com.hs.filter;

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.HttpServletResponse;


/**
 * @ClassName: CORSFilter
 * @Description: 跨域過濾,正式部署時如果相同域名下建議不使用
 * @author xiaoming
 * @date 2018/06/29 16:59:46
 */
public class CORSFilter implements Filter {
    @Override
    public void init(FilterConfig var1) throws ServletException {}

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
     HttpServletResponse response = (HttpServletResponse) servletResponse;
        response.addHeader("Access-Control-Allow-Origin", "*");
        filterChain.doFilter(servletRequest, servletResponse);
    }

    public void destroy() {}
}

2. web.xml

  <filter>
  	<filter-name>CORSFilter</filter-name>
  	<filter-class>com.xx.filter.CORSFilter</filter-class>
  </filter>
  <filter-mapping>
  	<filter-name>CORSFilter</filter-name>
  	<url-pattern>/*</url-pattern>
  </filter-mapping>

Spring 4.2以后

跨域直接通過注解方式, 因為沒有實際使用暫不做說明, 網上有很多