跨域问题：Access-Control-Allow-Origin

野性酷女 2021-09-21 16:58 211阅读 0赞

> **博客来源：**
> 
> 项目合作的时候，出现跨域访问，虽然种种迹象表明、跨域不安全、对于合作项目，来说跨域也不是不可
> 
> 解决办法：【项目完结后将跨域取消即可】

### 修改跨域问题在Java后端解决 ###

web.xml中

<filter>
        <filter-name>crossDomain</filter-name>
        <filter-class>online.wenmeng.filter.crossDomain</filter-class>
      </filter>
      <filter-mapping>
        <filter-name>CharacterEncodingFilter</filter-name>
        <url-pattern>/*</url-pattern>
      </filter-mapping>

crossDomain 复制这个类，放到你的项目中【要与上面过滤器中class对应】

package online.wenmeng.filter;
    
    import javax.servlet.*;
    import javax.servlet.http.HttpServletResponse;
    import java.io.IOException;
    
    /**
     * @Descrintion: 解决跨域问题的过滤器
     * @version: 1.0
     */
    public class crossDomain implements Filter {
    
        @Override
        public void init(FilterConfig filterConfig) throws ServletException {
    
        }
    
        @Override
        public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain) throws IOException, ServletException {
            // 将ServletResponse转换为HttpServletResponse
            HttpServletResponse httpResponse = (HttpServletResponse) res;
            httpResponse.setHeader("Access-Control-Allow-Origin", "*");
            httpResponse.setContentType("application/json;charset=UTF-8");
            httpResponse.setHeader("Access-Control-Allow-Methods", "GET, HEAD, POST, PUT, DELETE, OPTIONS, PATCH");
            httpResponse.setHeader("Access-Control-Max-Age", "3600");
            httpResponse.setHeader("Access-Control-Allow-Headers", "Content-Type,Access-Token");
            // 如果要把Cookie发到服务器，需要指定Access-Control-Allow-Credentials字段为true
            httpResponse.setHeader("Access-Control-Allow-Credentials", "true");
            httpResponse.setHeader("Access-Control-Expose-Headers", "*");
            chain.doFilter(req, res);
        }
    
        @Override
        public void destroy() {
    
        }
    }

### 重启项目，或者重新打包上传到云服务器，跨域问题解决 ###