filter java 怎么写

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filter java 怎么写,第1张

web.xml配置文件

<filter>

<filter-name>SessionFilter</filter-name>

<filter-class>com.qhit.system.tools.SessionFilter</filter-class>

</filter>

<filter-mapping>

<filter-name>SessionFilter</filter-name>

<url-pattern>/*</url-pattern>

</filter-mapping>

java类

public class ConnFilter extends HttpServlet implements Filter {

public void doFilter(ServletRequest request, ServletResponse response,

FilterChain filterchain) throws IOException, ServletException

{

try

{

filterchain.doFilter(request, response)此处为过滤链 理解为请求通过该过滤继续前行 可在此处加上判断 如果TRUE执行该语句 有过FALSE 则直接跳转其他页面 常用于判断是否有权限进入某页面

}

finally

{

DBUtils.close()

}

}

web.xml配置文件

SessionFilter

com.qhit.system.tools.SessionFilter

SessionFilter

/*

java类

public class ConnFilter extends HttpServlet implements Filter {

public void doFilter(ServletRequest request,ServletResponse response,

FilterChain filterchain) throws IOException,ServletException

{

try

{

filterchain.doFilter(request,response)此处为过滤链 理解为请求通过该过滤继续前行 可在此处加上判断 如果TRUE执行该语句 有过FALSE 则直接跳转其他页面 常用于判断是否有权限进入某页面

}

finally

{

DBUtils.close()

}

}

当我们访问index.jsp/时,其实并不是我们浏览器真正访问到了服务器上的index.jsp 文件,而是先由代理服务器去访问index.jsp。

代理服务器再将访问到的结果返回给我们的浏览器,因为是代理服务器去访问index.jsp的。

所以index.jsp中通过 request.getRemoteAddr()的方法获取的IP实际上是代理服务器的地址,并不是客户端的IP地址。

于是可得出获得客户端真实IP地址 的方法:

public class Myfilter implements Filter { 

public void destroy() {

}

private HttpServletRequest request

private HttpServletResponse response

public void doFilter(ServletRequest arg0, ServletResponse arg1, FilterChain arg2) throws IOException, ServletException {

request = (HttpServletRequest) arg0

response = (HttpServletResponse) arg1

System.out.println(request.getRequestURI())

System.out.println("===ff===="+request.getQueryString())

if("1".equals(request.getRequestURI().substring(("/"+request.getContextPath()).length()))){

request.getRequestDispatcher("/my.jsp").forward(request, response)

return

}

arg2.doFilter(request, arg1)

}

public void init(FilterConfig arg0) throws ServletException {

}

}