//ArgsIsValidFilter .java过滤器代码清单：
package com.hety.uitl;

import java.io.IOException;
import java.util.Enumeration;

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 org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

public class ArgsIsValidFilter implements Filter {

private static Log log = LogFactory.getLog(ArgsIsValidFilter.class);

public void destroy() {

}

@SuppressWarnings("unchecked")
public void doFilter(ServletRequest arg0, ServletResponse arg1, FilterChain arg2) throws IOException, ServletException {
HttpServletRequest request = (HttpServletRequest) arg0;
HttpServletResponse response = (HttpServletResponse) arg1;
String servername_str = request.getServerName();
String currentURI = request.getRequestURI();
Enumeration headerValues = request.getHeaders("Referer");
String tmpHeaderValue = "";
boolean isValid = true;
//指定需要跳过拦截的页面地址，如果需要新增，可直接在数组中添加。
//“建议”
String [] ignoreURIS={"/back/",
"/Info.jsp",
"/pzxx.jsp"
};
while (headerValues.hasMoreElements()) {
// 得到完整的路径：如“http://www.domain.com.cn:8023/front/zwgk/zwgk.jsp?id=1283”
tmpHeaderValue = (String) headerValues.nextElement();
}

if(log.isInfoEnabled()){
log.info(" 获得的参数url为: " + tmpHeaderValue );
log.info(" 系统取得的url为："+ currentURI);
}

if ("".equals(tmpHeaderValue)) {
isValid = false;
if(log.isInfoEnabled()){
log.info(" 获得的参数url为: empty");
log.info(" 系统取得的url为："+ currentURI);
log.info("系统提示：请求可能来自外域！");
}

} else {
if(log.isInfoEnabled()){
log.info("获得的参数长度为:"+tmpHeaderValue.length());
}
tmpHeaderValue = tmpHeaderValue.toLowerCase();
servername_str = servername_str.toLowerCase();

int len = 0;
if (tmpHeaderValue.startsWith("https://")) {
len = 8;
} else if (tmpHeaderValue.startsWith("http://")) {
len = 7;
}

if(log.isInfoEnabled()){
log.info("截取前的字符串为：" + tmpHeaderValue );
log.info( "从第 " + len + " 位开始截取，截取长度为：" + servername_str.length());
}
String tmp = tmpHeaderValue.substring(len, servername_str.length() + len);
if(log.isInfoEnabled()){
log.info("截取后的字符串为：" + tmp);
}
if (tmp.length() < servername_str.length()) { // 长度不够
isValid = false;
if(log.isInfoEnabled()){
log.info("截取后的字符串长度不够,请求可能来自外域！");
}
} else if (!tmp.equals(servername_str)) {// 比较字符串（主机名称）是否相同
isValid = false;
if(log.isInfoEnabled()){
log.info("域名匹配失败，请求来自外域！");
}
}
}


// 跳过指定需要拦截的页面地址
for (String ignoreURI : ignoreURIS) {
if(currentURI.contains(ignoreURI)){
isValid=true;
if(log.isInfoEnabled()){
log.info("系统已跳过检查以下url："+currentURI);
}
}
}

if (!isValid) {

if(log.isInfoEnabled()){
log.info("系统提示信息：URL为跨域请求，即将重定向到首页。 ");
}
response.sendRedirect("/index.html");
} else {
arg2.doFilter(arg0, arg1);
}
}

public void init(FilterConfig arg0) throws ServletException {

}

}