原 ssm框架解决跨域问题

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一：自定义一个Filter。

package com.fyq.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.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.fyq.utils.ConstantUtils;

// 设置跨域[http升级为https后引起跨域问题]
public class CorsFilter implements Filter {
	
	private boolean isCross = false;
	

	@Override
	public void init(FilterConfig filterConfig) throws ServletException {
		String isCrossStr = filterConfig.getInitParameter("IsCross");
        isCross = isCrossStr.equals("true") ? true : false;
        // System.out.println(isCrossStr);
	}
	
	@Override
	public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
			throws IOException, ServletException {
		if (isCross) {
            // HttpServletRequest httpServletRequest = (HttpServletRequest) request;
            HttpServletResponse httpServletResponse = (HttpServletResponse) response;
            // System.out.println("拦截请求: " + httpServletRequest.getServletPath());
            
            httpServletResponse.setHeader("Access-Control-Allow-Origin", ConstantUtils.CROSS_ORIGIN);
            httpServletResponse.setHeader("Access-Control-Allow-Methods", "POST, GET, OPTIONS, DELETE");
            httpServletResponse.setHeader("Access-Control-Max-Age", "0");
            httpServletResponse.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");
            httpServletResponse.setHeader("Access-Control-Allow-Credentials", "true"); // 设置cookie
            httpServletResponse.setHeader("XDomainRequestAllowed", "1");
        }
        chain.doFilter(request, response);
	}

	@Override
	public void destroy() {
		isCross = false;
	}
	

}

二：在web.xml中配置如下

<!-- 跨域请求  -->
  <filter>
       <filter-name>SimpleCORSFilter</filter-name>
       <filter-class>com.fyq.filter.CorsFilter</filter-class>
       <init-param>
           <param-name>IsCross</param-name>
           <param-value>true</param-value>
       </init-param>
   </filter>
   <filter-mapping>
       <filter-name>SimpleCORSFilter</filter-name>
       <url-pattern>/*</url-pattern>
  </filter-mapping>

三：在spring-mvc.xml中配置如下。

<!-- 跨域配置  -->
    <mvc:cors>
	    <mvc:mapping path="/**/*"  
	        allowed-origins="*" 
	        allowed-methods="POST, GET, OPTIONS, DELETE, PUT" 
	        allowed-headers="Content-Type, Access-Control-Allow-Headers, Authorization, X-Requested-With" 
	        allow-credentials="true" />
    </mvc:cors>

注意：

一：有个比较坑的问题，可能你这样设置后还是无法解决跨域问题。如果你的请求是这样写的，那么恭喜你中奖了，还是无法解决跨域问题。

@RequestMapping(value="/userlogin", method=RequestMethod.GET)

正确的写法如下：

@RequestMapping("/userlogin")

不能指定请求的类型，具体原因我没想太明白。希望能帮忙到各位小伙伴们。

二：这样设置后，解决了跨域问题，但是如果是ajax请求的话，无法从session中获取到值。如登录后将用户的信息放入到session里面，但是你却无法获取到session里面的值，解决办法如下。加上xhrFields:{withCredentials:true},crossDomain:true即可。

$.ajax({
    type:"post",
    xhrFields:{withCredentials:true},
    crossDomain:true,
    url:"",
    data:"",
    success: function(data){
				
    }
})