ssm项目跨域访问

最近使用ssm开发了一个项目，为了项目的开发速度，采用的是前后端同时开发，所以前端文件没有集成在项目中，最后在调试时涉及到了跨域。跨域的解决方法很多，我采用的是最简单的一种，代码如下：

新建一个过滤器filter

package com.xxxx.xxxxx;

import javax.servlet.*;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

public class SimpleCORSFilter implements Filter {

    @Override
    public void destroy() {
    }

    @Override
    public void doFilter(ServletRequest req, ServletResponse res,FilterChain chain) throws IOException, ServletException {
        HttpServletResponse response = (HttpServletResponse) res;
        response.setHeader("Access-Control-Allow-Origin", "*");
        response.setHeader("Access-Control-Allow-Methods", "POST, GET, OPTIONS, DELETE");
        response.setHeader("Access-Control-Max-Age", "3600");
        response.setHeader("Access-Control-Allow-Headers", "x-requested-with");
        chain.doFilter(req, res);
    }

    @Override
    public void init(FilterConfig arg0) throws ServletException {
    }

}

然后在xml中配置

<filter>
      <filter-name>cors</filter-name>
      <filter-class>com.ssm.web.filter.SimpleCORSFilter</filter-class>
</filter>
<filter-mapping>
      <filter-name>cors</filter-name>
      <url-pattern>/*</url-pattern>
</filter-mapping>

　　2018.08.07更新

　　由于项目的升级，感觉以前的filter不满足实际需求，故而进行扩展升级

　　

　　filter

package com.xxx.xxx;

import org.springframework.stereotype.Component;
import javax.servlet.*;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

@Component
public class CORSFilter implements Filter {

    // 存放跨域的白名单
    private String[] permitUrl;

    @Override
    public void doFilter(ServletRequest req, ServletResponse res,FilterChain chain) throws IOException, ServletException {
        HttpServletResponse response = (HttpServletResponse) res;
        HttpServletRequest request = (HttpServletRequest) req;

        String myOrigin = request.getHeader("origin");
        boolean isValid = false;
        for (String ip : permitUrl) {
            if (myOrigin != null && myOrigin.equals(ip)) {
                isValid = true;
                break;
            }
        }

        response.setContentType("textml;charset=UTF-8");
        response.setHeader("Access-Control-Allow-Origin", isValid ? myOrigin : "null");
        response.setHeader("Access-Control-Allow-Methods", "POST, GET, OPTIONS, DELETE");
        response.setHeader("Access-Control-Max-Age", "3600");
        response.setHeader("Access-Control-Allow-Headers", "Origin, No-Cache, X-Requested-With, If-Modified-Since, Pragma, Last-Modified, Cache-Control, Expires, Content-Type, X-E4M-With,userId,token");
        response.setHeader("Access-Control-Allow-Credentials", "true");
        response.setHeader("P3P", "CP=\"NON DSP COR CURa ADMa DEVa TAIa PSAa PSDa IVAa IVDa CONa HISa TELa OTPa OUR UNRa IND UNI COM NAV INT DEM CNT PRE LOC\"");
        response.setHeader("XDomainRequestAllowed", "1");

        chain.doFilter(req, res);
    }

    // 初始化方法，这里的permitUrl是在web.xml中配置的
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
        String urls = filterConfig.getInitParameter("permitUrl");
        if (urls != null) {
            urls = urls.replaceAll("\\n", "").replaceAll("\\r", "").replaceAll("\\t", "");
        }
        if (!"".equals(urls) && urls != null) {
            permitUrl = urls.split(",");
        }
        if (permitUrl != null) {
            for (int i = 0; i < permitUrl.length; i++) {
                permitUrl[i] = permitUrl[i].trim();
            }
        }
    }

    // 销毁方法
    @Override
    public void destroy() {
    }

}

　　web.xml中配置(这里的permitUrl中的value就是你项目允许的ip地址，不允许的将访问不到)

<filter>
        <filter-name>cors</filter-name>
        <filter-class>com.xxx.xxx.CORSFilter</filter-class>
        <init-param>
            <param-name>permitUrl</param-name>
            <param-value>
                http://192.168.1.51:3000,
                http://192.168.1.51:8020,
                http://www.baidu.com:8084
            </param-value>
        </init-param>
    </filter>
    <filter-mapping>
        <filter-name>cors</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>