filter如何设置例外的请求

在web.xml声明的一个filter中：

<!– session过滤filter –>
<filter>
<filter-name>SessionFilter</filter-name>
<filter-class>
com.iqbon.jcms.web.util.SessionFilter
</filter-class>
<init-param>
<param-name>excludedPages</param-name>
<param-value>/admin/login.do</param-value>
</init-param>
</filter>
<filter-mapping>
<filter-name>SessionFilter</filter-name>
<url-pattern>/admin/*</url-pattern>
</filter-mapping>

 

可以看到url-pattern的设置里面过滤的url规则是/admin/*，如果要把/admin/login.do排除在过滤url之外。

可以结合init-param的初始化参数和HttpServletRequest的getServletPath()方法来判断。

 

首先加上初始化参数：

<init-param>
<param-name>excludedPages</param-name>
<param-value>/admin/login.do</param-value>
</init-param>

 其次在filter的java代码中加上判断：

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 javax.servlet.http.HttpSession;

import org.apache.commons.lang3.StringUtils;

import com.iqbon.jcms.util.KeyConstant;

/**
* session过滤器
*/
public class SessionFilter implements Filter {

/**
* 需要排除的页面
*/
private String excludedPages;

private String[] excludedPageArray;
/**
* @see Filter#destroy()
*/
public void destroy() {
return;
}

/**
* 对session进行判断当前访问是否有登录
*/
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
boolean isExcludedPage = false;
for (String page : excludedPageArray) {//判断是否在过滤url之外
if(((HttpServletRequest) request).getServletPath().equals(page)){
isExcludedPage = true;
break;
}
}
if (isExcludedPage) {//在过滤url之外
chain.doFilter(request, response);
} else {//不在过滤url之外，判断session是否存在
HttpSession session = ((HttpServletRequest) request).getSession();
if (session == null || session.getAttribute(KeyConstant.SESSION_KEY_USER) == null) {
((HttpServletResponse) response).sendRedirect(“/login.htm”);
} else {
chain.doFilter(request, response);
}
}
}

/**
* 初始化函数，获取需要排除在外的url
*/
public void init(FilterConfig fConfig) throws ServletException {
excludedPages = fConfig.getInitParameter(“excludedPages”);
if (StringUtils.isNotEmpty(excludedPages)) {
excludedPageArray = excludedPages.split(“,”);
}
return;
}

}