2019-05-31 15:13:32 3712瀏覽
今天千鋒扣丁學(xué)堂Java培訓(xùn)老師給大家分享一篇關(guān)于深入了解Java中Filter過濾器的詳細(xì)介紹，首先Filter也稱之為過濾器，它是Servlet技術(shù)中最實(shí)用的技術(shù)，WEB開發(fā)人員通過Filter技術(shù)，對(duì)web服務(wù)器管理的所有web資源：例如Jsp,Servlet,靜態(tài)圖片文件或靜態(tài)html文件等進(jìn)行攔截，從而實(shí)現(xiàn)一些特殊的功能。例如實(shí)現(xiàn)URL級(jí)別的權(quán)限訪問控制、過濾敏感詞匯、壓縮響應(yīng)信息等一些高級(jí)功能。
public void init(FilterConfig filterConfig) throws ServletException;//初始化
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException;//攔截請(qǐng)求
public void destroy();//銷毀
String getFilterName();//得到filter的名稱。 String getInitParameter(String name);//返回在部署描述中指定名稱的初始化參數(shù)的值。如果不存在返回null. Enumeration getInitParameterNames();//返回過濾器的所有初始化參數(shù)的名字的枚舉集合。 public ServletContext getServletContext();//返回Servlet上下文對(duì)象的引用。
<filter> <filter-name>SessionFilter</filter-name> <filter-class>com.action.login.SessionFilter</filter-class> <init-param> <param-name>logonStrings</param-name><!-- 對(duì)登錄頁(yè)面不進(jìn)行過濾 --> <param-value>/project/index.jsp;login.do</param-value> </init-param> <init-param> <param-name>includeStrings</param-name><!-- 只對(duì)指定過濾參數(shù)后綴進(jìn)行過濾 --> <param-value>.do;.jsp</param-value> </init-param> <init-param> <param-name>redirectPath</param-name><!-- 未通過跳轉(zhuǎn)到登錄界面 --> <param-value>/index.jsp</param-value> </init-param> <init-param> <param-name>disabletestfilter</param-name><!-- Y:過濾無(wú)效 --> <param-value>N</param-value> </init-param> </filter> <filter-mapping> <filter-name>SessionFilter</filter-name> <url-pattern>/*</url-pattern> </filter-mapping>
package com.action.login;
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.HttpServletResponseWrapper;
/**
* 判斷用戶是否登錄,未登錄則退出系統(tǒng)
*/
public class SessionFilter implements Filter {
public FilterConfig config;
public void destroy() {
this.config = null;
}
public static boolean isContains(String container, String[] regx) {
boolean result = false;
for (int i = 0; i < regx.length; i++) {
if (container.indexOf(regx[i]) != -1) {
return true;
}
}
return result;
}
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
HttpServletRequest hrequest = (HttpServletRequest)request;
HttpServletResponseWrapper wrapper = new HttpServletResponseWrapper((HttpServletResponse) response);
String logonStrings = config.getInitParameter("logonStrings"); // 登錄登陸頁(yè)面
String includeStrings = config.getInitParameter("includeStrings"); // 過濾資源后綴參數(shù)
String redirectPath = hrequest.getContextPath() + config.getInitParameter("redirectPath");// 沒有登陸轉(zhuǎn)向頁(yè)面
String disabletestfilter = config.getInitParameter("disabletestfilter");// 過濾器是否有效
if (disabletestfilter.toUpperCase().equals("Y")) { // 過濾無(wú)效
chain.doFilter(request, response);
return;
}
String[] logonList = logonStrings.split(";");
String[] includeList = includeStrings.split(";");
if (!this.isContains(hrequest.getRequestURI(), includeList)) {// 只對(duì)指定過濾參數(shù)后綴進(jìn)行過濾
chain.doFilter(request, response);
return;
}
if (this.isContains(hrequest.getRequestURI(), logonList)) {// 對(duì)登錄頁(yè)面不進(jìn)行過濾
chain.doFilter(request, response);
return;
}
String user = ( String ) hrequest.getSession().getAttribute("useronly");//判斷用戶是否登錄
if (user == null) {
wrapper.sendRedirect(redirectPath);
return;
}else {
chain.doFilter(request, response);
return;
}
}
public void init(FilterConfig filterConfig) throws ServletException {
config = filterConfig;
}
}
<filter> <filter-name>encoding</filter-name> <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class> <init-param> <param-name>encoding</param-name><!--用來(lái)指定一個(gè)具體的字符集--> <param-value>UTF-8</param-value> </init-param> <init-param> <param-name>forceEncoding</param-name><!--true：無(wú)論request是否指定了字符集，都是用encoding；false：如果request已指定一個(gè)字符集，則不使用encoding--> <param-value>false</param-value> </init-param> </filter> <filter-mapping> <filter-name>encoding</filter-name> <url-pattern>/*</url-pattern> </filter-mapping>
<filter><!-- lazy loading enabled in spring --> <filter-name>OpenSessionInViewFilter</filter-name> <filter-class>org.springframework.orm.hibernate3.support.OpenSessionInViewFilter</filter-class> <init-param> <param-name>sessionFactoryBeanName</param-name><!-- 可缺省。默認(rèn)是從spring容器中找id為sessionFactory的bean，如果id不為sessionFactory，則需要配置如下，此處SessionFactory為spring容器中的bean。 --> <param-value>sessionFactory</param-value> </init-param> <init-param> <param-name>singleSession</param-name><!-- singleSession默認(rèn)為true,若設(shè)為false則等于沒用OpenSessionInView --> <param-value>true</param-value> </init-param> </filter> <filter-mapping> <filter-name>OpenSessionInViewFilter</filter-name> <url-pattern>*.do</url-pattern> </filter-mapping>
<!-- struts 2.x filter --> <filter> <filter-name>struts2</filter-name> <filter-class>org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter</filter-class> </filter> <filter-mapping> <filter-name>struts2</filter-name> <url-pattern>*.do</url-pattern> </filter-mapping>
【關(guān)注微信公眾號(hào)獲取更多學(xué)習(xí)資料】 【掃碼進(jìn)入Python全棧開發(fā)免費(fèi)公開課】
查看更多關(guān)于“大數(shù)據(jù)培訓(xùn)資訊”的相關(guān)文章>
全國(guó)免費(fèi)咨詢熱線
郵箱：codingke@1000phone.com
官方群：148715490
返回頂部