XSS攻击：跨站脚本攻击(Cross Site Scripting)，为不和层叠样式表(Cascading Style Sheets, CSS)的缩写混淆，故将跨站脚本攻击缩写为XSS。
以下为Java web项目中的解决方案：
Filter代码：
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 org.apache.commons.lang.StringUtils;
import com.fengling.core.web.util.URLHelper;
public class XssFilter implements Filter {
private String filterChar;
private String replaceChar;
private String splitChar;
private String excludeUrls;
FilterConfig filterConfig = null;
public void init(FilterConfig filterConfig) throws ServletException {
this.filterChar=filterConfig.getInitParameter("FilterChar");
this.replaceChar=filterConfig.getInitParameter("ReplaceChar");
this.splitChar=filterConfig.getInitParameter("SplitChar");
this.excludeUrls=filterConfig.getInitParameter("excludeUrls");
this.filterConfig = filterConfig;
}
public void destroy() {
this.filterConfig = null;
}
public void doFilter(ServletRequest request, ServletResponse response,
FilterChain chain) throws IOException, ServletException {
if(isExcludeUrl(request)){
chain.doFilter(request, response);
}else{
chain.doFilter(new XssHttpServletRequestWrapper((HttpServletRequest) request,filterChar,replaceChar,splitChar), response);
}
}
private boolean isExcludeUrl(ServletRequest request){
boolean exclude=false;
if(StringUtils.isNotBlank(excludeUrls)){
String[]excludeUrl=excludeUrls.split(splitChar);
if(excludeUrl!=null&&excludeUrl.length>0){
for(String url:excludeUrl){
if(URLHelper.getURI((HttpServletRequest)request).startsWith(url)){
exclude=true;
}
}
}
}
return exclude;
}
}
XssHttpServletRequestWrapper代码：
import java.io.UnsupportedEncodingException;
import java.net.URLDecoder; import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper; public class XssHttpServletRequestWrapper extends HttpServletRequestWrapper {
private String[]filterChars;
private String[]replaceChars;
public XssHttpServletRequestWrapper(HttpServletRequest request,String filterChar,String replaceChar,String splitChar) {
super(request);
if(filterChar!=null&&filterChar.length()>0){
filterChars=filterChar.split(splitChar);
}
if(replaceChar!=null&&replaceChar.length()>0){
replaceChars=replaceChar.split(splitChar);
}
}
public String getQueryString() {
String value = super.getQueryString();
if (value != null) {
value = xssEncode(value);
}
return value;
} /**
* 覆盖getParameter方法，将参数名和参数值都做xss过滤。<br/>
* 如果需要获得原始的值，则通过super.getParameterValues(name)来获取<br/>
* getParameterNames,getParameterValues和getParameterMap也可能需要覆盖
*/
public String getParameter(String name) {
String value = super.getParameter(xssEncode(name));
if (value != null) {
value = xssEncode(value);
}
return value;
} public String[] getParameterValues(String name) {
String[]parameters=super.getParameterValues(name);
if (parameters==null||parameters.length == 0) {
return null;
}
for (int i = 0; i < parameters.length; i++) {
parameters[i] = xssEncode(parameters[i]);
}
return parameters;
} /**
* 覆盖getHeader方法，将参数名和参数值都做xss过滤。<br/>
* 如果需要获得原始的值，则通过super.getHeaders(name)来获取<br/> getHeaderNames 也可能需要覆盖
*/
public String getHeader(String name) { String value = super.getHeader(xssEncode(name));
if (value != null) {
value = xssEncode(value);
}
return value;
} /**
* 将容易引起xss漏洞的半角字符直接替换成全角字符
*
* @param s
* @return
*/
private String xssEncode(String s) {
if (s == null || s.equals("")) {
return s;
}
try {
s = URLDecoder.decode(s, "UTF8");
} catch (UnsupportedEncodingException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
for (int i = 0; i < filterChars.length; i++) {
if(s.contains(filterChars[i])){
s=s.replace(filterChars[i], replaceChars[i]);
}
}
return s;
}
}
web.xml中配置：
<!--@分隔-->
<filter>
<filter-name>XssFilter</filter-name>
<filter-class>com.fengling.common.web.XssFilter</filter-class>
<init-param>
<param-name>excludeUrls</param-name>
<param-value>/member/contribute@/admin/fengling@/flow_statistic</param-value>
</init-param>
<init-param>
<param-name>SplitChar</param-name>
<param-value>@</param-value>
</init-param>
<init-param>
<param-name>FilterChar</param-name>
<param-value>'@"@\@#@:@%@;@></param-value>
</init-param>
<init-param>
<param-name>ReplaceChar</param-name>
<param-value>‘@“@＼@＃@：@％@；@＞</param-value>
</init-param>
</filter>
<filter-mapping>
<filter-name>XssFilter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>