filter如何设置例外的请求

在web.xml声明的一个filter中：

Xml代码


<!– 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：

Xml代码


<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：

Java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 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;

}

}