前后端分离跨域问题

1.理解跨域问题：

2.如何解决：

http://blog.csdn.net/zhang6622056/article/details/75570518

https://blog.csdn.net/zhang6622056/article/details/75221492

跨域问题实战：

需要改动三个地方：

1 2 3

1对应代码：

<dependency>

          <groupId>javax.servlet</groupId>

          <artifactId>javax.servlet-api</artifactId>

          <version>4.0.1</version>

      </dependency>

2.对应代码：

<!-- 2019-04-26 解决跨域问题 -->

  <filter>

    <filter-name>crossFilter</filter-name>

    <filter-class>com.crup.political.filter.CorsFilter</filter-class>

  </filter>

  <filter-mapping>

    <filter-name>crossFilter</filter-name>

    <url-pattern>/*</url-pattern>

  </filter-mapping>

3对应代码：

/**

* 解决跨域

*/

public class CorsFilterimplements Filter {

@Override

    public void destroy() {

// TODO Auto-generated method stub

    }

@Override

    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)

throws IOException, ServletException {

HttpServletResponse httpServletResponse = (HttpServletResponse) response;

        httpServletResponse.setHeader("Access-Control-Allow-Origin", "*");

        httpServletResponse.setHeader("Access-Control-Allow-Headers", "accept,content-type");

        httpServletResponse.setHeader("Access-Control-Allow-Methods", "OPTIONS,GET,POST,DELETE,PUT");

        chain.doFilter(request, httpServletResponse);

    }

@Override

    public void init(FilterConfig arg0)throws ServletException {

// TODO Auto-generated method stub

    }

}