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JavaWeb中监听器+过滤器+拦截器区别、配置和实际应用

2017-08-11 09:07 549 查看

JavaWeb中监听器+过滤器+拦截器区别、配置和实际应用

1.前沿上一篇文章提到在web.xml中各个元素的执行顺序是这样的，context-param-->listener-->filter-->servlet；而拦截器是在Spring MVC中配置的，如果从整个项目中看，一个servlet请求的执行过程就变成了这样context-param-->listener-->filter-->servlet-->interceptor(指的是拦截器)，为什么拦截器是在servlet执行之后，因为拦截器本身就是在servlet内部的，下面把所学和所总结的用自己的描述整理出来~。另外本文的项目框架是基于上篇文章http://blog.csdn.net/Jintao_Ma/article/details/52892625
讲述的框架，下载路径：http://download.csdn.net/download/jintao_ma/9661038。

2.概念

context-param：就是一些需要初始化的配置，放入context-param中，从而被监听器（这里特指org.springframework.web.context.ContextLoaderListener）监听，然后加载；

监听器(listener)：就是对项目起到监听的作用，它能感知到包括request(请求域)，session(会话域)和applicaiton(应用程序)的初始化和属性的变化；

过滤器(filter)：就是对请求起到过滤的作用，它在监听器之后，作用在servlet之前，对请求进行过滤；

servlet：就是对request和response进行处理的容器，它在filter之后执行，servlet其中的一部分就是controller层（标记为servlet_2），还包括渲染视图层(标记为servlet_3)和进入controller之前系统的一些处理部分(servlet_1)，另外我们把servlet开始的时刻标记为servlet_0，servlet结束的时刻标记为servlet_4。

拦截器(interceptor)：就是对请求和返回进行拦截，它作用在servlet的内部，具体来说有三个地方：

1）servlet_1和servlet_2之间，即请求还没有到controller层

2）servlet_2和servlet_3之间，即请求走出controller层次，还没有到渲染时图层

3）servlet_3和servlet_4之间，即结束视图渲染，但是还没有到servlet的结束

它们之间的关系，可以用一张图来表示：

3.使用原则

对整个流程清楚之后，然后就是各自的使用，在使用之前应该有一个使用规则，为什么这个说，因为有些功能比如判断用户是否登录，既可以用过滤器，也可以用拦截器，用哪一个才是合理的呢？那么如果有一个原则，使用起来就会更加合理。实际上这个原则是有的：

把整个项目的流程比作一条河，那么监听器的作用就是能够听到河流里的所有声音，过滤器就是能够过滤出其中的鱼，而拦截器则是拦截其中的部分鱼，并且作标记。所以当需要监听到
1d25c
项目中的一些信息，并且不需要对流程做更改时，用监听器；当需要过滤掉其中的部分信息，只留一部分时，就用过滤器；当需要对其流程进行更改，做相关的记录时用拦截器。下面是具体的使用案例

本文涉及到的jsp页面：

index.jsp:

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<%@ page language="java"  import="com.mycompany.mvc.listener.*" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>index.jsp</title>
</head>
<body>
this is index jsp

<a href="/myWebApp/system/login">login</a>
<br></br>
测试servletcontext：
<%
application.setAttribute("app","app");
application.getAttribute("app");
application.removeAttribute("app");
%>
<br></br>
测试httpsession:
<%
session.setAttribute("app3","app3");
session.getAttribute("app3");
session.removeAttribute("app3");
%>
<br></br>
测试servletrequest:
<%
request.setAttribute("app3","app3");
request.getAttribute("app3");
request.removeAttribute("app3");
%>
<br></br>
当前在线人数：
<%=session.getAttribute("peopleOnLine")%>
<br></br>
HttpSessionBindingListener测试：
<%
session.setAttribute("bean",new myHttpSessionBindingListener());
session.removeAttribute("bean");
%>
</body>
</html>

<%@ page language="java"  import="com.mycompany.mvc.listener.*" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>index.jsp</title>
</head>
<body>
this is index jsp
<!-- 这里应该填入用户名和密码 -->
<a href="/myWebApp/system/login">login</a>
<br></br>
测试servletcontext：
<%
application.setAttribute("app","app");
application.getAttribute("app");
application.removeAttribute("app");
%>
<br></br>
测试httpsession:
<%
session.setAttribute("app3","app3");
session.getAttribute("app3");
session.removeAttribute("app3");
%>
<br></br>
测试servletrequest:
<%
request.setAttribute("app3","app3");
request.getAttribute("app3");
request.removeAttribute("app3");
%>
<br></br>
当前在线人数：
<%=session.getAttribute("peopleOnLine")%>
<br></br>
HttpSessionBindingListener测试：
<%
session.setAttribute("bean",new myHttpSessionBindingListener());
session.removeAttribute("bean");
%>
</body>
</html>

<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>main.jsp</title>
</head>

<c:set var="ctx"  value="${pageContext.request.scheme}://${pageContext.request.serverName}:${pageContext.request.serverPort}${pageContext.request.contextPath}" />
<script type="text/javascript" src="${ctx}/plugins/jquery-3.0.0/jquery-3.0.0.js"></script>
<script type="text/javascript">
</script>

<body>
This is has login jsp
<a href="/myWebApp/system/view">view</a>
</body>
</html>

<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>main.jsp</title>
</head>

<c:set var="ctx"  value="${pageContext.request.scheme}://${pageContext.request.serverName}:${pageContext.request.serverPort}${pageContext.request.contextPath}" />
<script type="text/javascript" src="${ctx}/plugins/jquery-3.0.0/jquery-3.0.0.js"></script>
<script type="text/javascript">
</script>

<body>
This is has login jsp
<a href="/myWebApp/system/view">view</a>
</body>
</html>

view.jsp:

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<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>view jsp</title>
</head>
<body>
用户已经登陆，欢迎来到登陆后系统主界面
</body>
</html>

<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>view jsp</title>
</head>
<body>
用户已经登陆，欢迎来到登陆后系统主界面
</body>
</html>

4.监听器

4.1listener具体分为八种，能够监听包括request域，session域，application域的产生，销毁和属性的变化；

具体使用，可以看之前转载一篇文章（再次感谢"孤傲苍狼"，他的主页http://www.cnblogs.com/xdp-gacl/）：http://blog.csdn.net/Jintao_Ma/article/details/51464124

在配置完然后我们在web.xml中诸如下面的配置即可：

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<listener> <listener-class>
        com.mycompany.mvc.listener.myServletContextListener
    </listener-class>
</listener>
<listener>
    <listener-class>
        com.mycompany.mvc.listener.myServletContextAttributeListener
    </listener-class>
</listener>

<listener> <listener-class>
com.mycompany.mvc.listener.myServletContextListener
</listener-class>
</listener>
<listener>
<listener-class>
com.mycompany.mvc.listener.myServletContextAttributeListener
</listener-class>
</listener>

4.2 listener实际应用

4.2.1 获取当前在线人数

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package com.mycompany.mvc.listener;

import javax.servlet.http.HttpSessionEvent;
import javax.servlet.http.HttpSessionListener;

public class myHttpSessionListener implements HttpSessionListener{

    public static int peopleOnLine = 0;

    @Override
    public void sessionCreated(HttpSessionEvent arg0) {
        System.out.println("myHttpSessionListener.sessionCreated():"+arg0);
        peopleOnLine++;
        arg0.getSession().setAttribute("peopleOnLine",peopleOnLine);
    }

    @Override
    public void sessionDestroyed(HttpSessionEvent arg0) {
        System.out.println("myHttpSessionListener.sessionDestroyed():"+arg0);
        peopleOnLine--;
        arg0.getSession().setAttribute("peopleOnLine",peopleOnLine);
    }
}

package com.mycompany.mvc.listener;

import javax.servlet.http.HttpSessionEvent;
import javax.servlet.http.HttpSessionListener;

public class myHttpSessionListener implements HttpSessionListener{

public static int peopleOnLine = 0;

@Override
public void sessionCreated(HttpSessionEvent arg0) {
System.out.println("myHttpSessionListener.sessionCreated():"+arg0);
peopleOnLine++;
arg0.getSession().setAttribute("peopleOnLine",peopleOnLine);
}

@Override
public void sessionDestroyed(HttpSessionEvent arg0) {
System.out.println("myHttpSessionListener.sessionDestroyed():"+arg0);
peopleOnLine--;
arg0.getSession().setAttribute("peopleOnLine",peopleOnLine);
}
}

在页面中就可以获取：

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当前在线人数：
<%=session.getAttribute("peopleOnLine")%>

当前在线人数：
<%=session.getAttribute("peopleOnLine")%>

其实也可以获得历史所有在线人数，只需要把历史所有在线人数保存在文件中，然后每次项目启动读取这个文件，当前人数增加时，把历史所有人数也相应增加，项目关闭时，再保存起来。

4.2.2 在系统初始化时，获取项目绝对路径

如下，获得绝对路径后保存到系统变量System中：

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@Override
public void contextInitialized(ServletContextEvent servletContext) {
    System.out.println("myServletContextListener.contextInitialized()");
    System.setProperty("realPath", servletContext.getServletContext().getRealPath("/"));
    System.out.println("myServletContextListener.contextInitialized()");
}

@Override
public void contextInitialized(ServletContextEvent servletContext) {
System.out.println("myServletContextListener.contextInitialized()");
System.setProperty("realPath", servletContext.getServletContext().getRealPath("/"));
System.out.println("myServletContextListener.contextInitialized()");
}

5.过滤器(filter)

5.1过滤器只需要继承javax.servlet.filter即可，一般来说我们只要添加tomcat运行时环境就能够包含javax.servlet的jar包，但是eclipse在tomcat8中没有找到，实际上tomcat8中确实没有，只有通过maven来添加了：

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<dependency>
        <groupId>javax.servlet</groupId>
        <artifactId>servlet-api</artifactId>
        <version>2.5</version>
    </dependency>


    <dependency>
        <groupId>javax.servlet</groupId>
        <artifactId>jsp-api</artifactId>
        <version>2.0</version>
    </dependency>

<!-- https://mvnrepository.com/artifact/javax.servlet/servlet-api -->
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>servlet-api</artifactId>
<version>2.5</version>
</dependency>

<!-- https://mvnrepository.com/artifact/javax.servlet/jsp-api -->
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>jsp-api</artifactId>
<version>2.0</version>
</dependency>

5.2 filter的实际应用

5.2.1 请求编码转换

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package com.mycompany.mvc.filter;

import java.io.IOException;
import java.util.HashMap;
import java.util.Map;

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 org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class urlEncodeFilter implements Filter{

    Logger logger = LoggerFactory.getLogger(urlEncodeFilter.class);
    Map<String,Object> paramMap = new HashMap<String,Object>();

    @Override
    public void destroy() {
    }

    @Override
    public void doFilter(ServletRequest arg0, ServletResponse arg1,
            FilterChain arg2) throws IOException, ServletException {
        System.out.println("urlEncodeFilter doFilter..."+paramMap.get("urlEncode").toString());
        arg0.setCharacterEncoding(paramMap.get("urlEncode").toString());
        arg2.doFilter(arg0, arg1);
    }

    @Override
    public void init(FilterConfig arg0) throws ServletException {
        String urlEncode = arg0.getInitParameter("urlEncode");
        paramMap.put("urlEncode",urlEncode);
    }

}

package com.mycompany.mvc.filter;

import java.io.IOException;
import java.util.HashMap;
import java.util.Map;

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 org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class urlEncodeFilter implements Filter{

Logger logger = LoggerFactory.getLogger(urlEncodeFilter.class);
Map<String,Object> paramMap = new HashMap<String,Object>();

@Override
public void destroy() {
}

@Override
public void doFilter(ServletRequest arg0, ServletResponse arg1,
FilterChain arg2) throws IOException, ServletException {
System.out.println("urlEncodeFilter doFilter..."+paramMap.get("urlEncode").toString());
arg0.setCharacterEncoding(paramMap.get("urlEncode").toString());
arg2.doFilter(arg0, arg1);
}

@Override
public void init(FilterConfig arg0) throws ServletException {
String urlEncode = arg0.getInitParameter("urlEncode");
paramMap.put("urlEncode",urlEncode);
}

}

web.xml配置：

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<filter>
    <filter-name>urlEncodeFilter</filter-name>
    <filter-class>com.mycompany.mvc.filter.urlEncodeFilter</filter-class>
    <init-param>
        <param-name>urlEncode</param-name>
        <param-value>UTF-8</param-value>
    </init-param>
</filter>

<filter>
<filter-name>urlEncodeFilter</filter-name>
<filter-class>com.mycompany.mvc.filter.urlEncodeFilter</filter-class>
<init-param>
<param-name>urlEncode</param-name>
<param-value>UTF-8</param-value>
</init-param>
</filter>

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<filter-mapping>
    <filter-name>urlEncodeFilter</filter-name>
    <url-pattern>/*</url-pattern>
</filter-mapping>

<filter-mapping>
<filter-name>urlEncodeFilter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>

5.2.2 日志记录，比如记录所有对网站发起请求的地址

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package com.mycompany.mvc.filter;

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.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class logFilter implements Filter{

Logger logger = LoggerFactory.getLogger(logFilter.class);

@Override
public void destroy() {

}

@Override
public void doFilter(ServletRequest arg0, ServletResponse arg1,
FilterChain arg2) throws IOException, ServletException {
HttpServletRequest request = (HttpServletRequest)arg0;
System.out.println("logFilter doFilter servletPath:"+request.getRemoteHost());
arg2.doFilter(arg0, arg1);
}

@Override
public void init(FilterConfig arg0) throws ServletException {
}

}

web.xml:

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<filter>
    <filter-name>logFilter</filter-name>
    <filter-class>com.mycompany.mvc.filter.logFilter</filter-class>
</filter>

<filter>
<filter-name>logFilter</filter-name>
<filter-class>com.mycompany.mvc.filter.logFilter</filter-class>
</filter>

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<filter-mapping>
    <filter-name>logFilter</filter-name>
    <url-pattern>/*</url-pattern>
</filter-mapping>

<filter-mapping>
<filter-name>logFilter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>

5.2.3 对未登陆用户的判断

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package com.mycompany.mvc.filter;

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.HttpSession;

import org.apache.commons.lang.StringUtils;

import com.mycompany.mvc.utils.Constant;

public class loginFilter implements Filter{

    private String dispatchUrl = "";
    private String excludeUrl = "";

    @Override
    public void destroy() {

    }

    @Override
    public void doFilter(ServletRequest arg0, ServletResponse arg1, FilterChain arg2)
            throws IOException, ServletException {
        HttpServletRequest request = (HttpServletRequest)arg0;
        String servletPath = request.getServletPath();

        HttpSession session = request.getSession();
        String sessionKey = (String) session.getAttribute(Constant.SESSIONKEY);

        /*就是登陆界面不进行过滤*/
        if(servletPath.equals(dispatchUrl) || servletPath.equals(excludeUrl)){
            arg2.doFilter(arg0, arg1);
        }else{
            if(!StringUtils.isEmpty(sessionKey)){
                arg2.doFilter(arg0, arg1);
            }else{
                request.getRequestDispatcher(dispatchUrl).forward(arg0, arg1);
            }
        }
    }

    @Override
    public void init(FilterConfig arg0) throws ServletException {
        dispatchUrl = arg0.getInitParameter("dispatchUrl");
        excludeUrl = arg0.getInitParameter("excludeUrl");
    }

}

package com.mycompany.mvc.filter;

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.HttpSession;

import org.apache.commons.lang.StringUtils;

import com.mycompany.mvc.utils.Constant;

public class loginFilter implements Filter{

private String dispatchUrl = "";
private String excludeUrl = "";

@Override
public void destroy() {

}

@Override
public void doFilter(ServletRequest arg0, ServletResponse arg1, FilterChain arg2)
throws IOException, ServletException {
HttpServletRequest request = (HttpServletRequest)arg0;
String servletPath = request.getServletPath();

HttpSession session = request.getSession();
String sessionKey = (String) session.getAttribute(Constant.SESSIONKEY);

/*就是登陆界面不进行过滤*/
if(servletPath.equals(dispatchUrl) || servletPath.equals(excludeUrl)){
arg2.doFilter(arg0, arg1);
}else{
if(!StringUtils.isEmpty(sessionKey)){
arg2.doFilter(arg0, arg1);
}else{
request.getRequestDispatcher(dispatchUrl).forward(arg0, arg1);
}
}
}

@Override
public void init(FilterConfig arg0) throws ServletException {
dispatchUrl = arg0.getInitParameter("dispatchUrl");
excludeUrl = arg0.getInitParameter("excludeUrl");
}

}

web.xml:

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<filter>
    <filter-name>loginFilter</filter-name>
    <filter-class>com.mycompany.mvc.filter.loginFilter</filter-class>
    <init-param>

        <param-name>excludeUrl</param-name>
        <param-value>/main</param-value>
    </init-param>
    <init-param>

        <param-name>dispatchUrl</param-name>
        <param-value>/system/login</param-value>
    </init-param>
</filter>

<filter>
<filter-name>loginFilter</filter-name>
<filter-class>com.mycompany.mvc.filter.loginFilter</filter-class>
<init-param>
<!-- 		不进行过滤的url，因为它就是跳转到登陆界面, -->
<param-name>excludeUrl</param-name>
<param-value>/main</param-value>
</init-param>
<init-param>
<!-- 		未登录用户跳转的url -->
<param-name>dispatchUrl</param-name>
<param-value>/system/login</param-value>
</init-param>
</filter>

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<filter-mapping>
    <filter-name>loginFilter</filter-name>
    <url-pattern>/*</url-pattern>
</filter-mapping>

<filter-mapping>
<filter-name>loginFilter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>

之所以上面的/main能够直接跳转到index这个登陆界面，是因为SpringMvc中配置了这个（上篇文章有讲述到）：

<mvc:view-controller path="${adminPath}" view-name="index"/>

它的意思就是不经过controller层，直接把index放入ModelAndView，然后由渲染层进行渲染。讲到这里，再结合上面说到的拦截器，我们发现，这个时候拦截器还是能够拦截2次的，就是视图渲染前和渲染后，但是进入controller层之前肯定拦截不到了，因为请求根本就没有进入controller。

systemAction:

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package com.mycompany.system.controller;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpSession;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.servlet.ModelAndView;

@Controller
@RequestMapping("/system")
public class systemAction {

    @RequestMapping("/login")
    public ModelAndView login(HttpServletRequest request){
        ModelAndView mv = new ModelAndView();
        HttpSession session = request.getSession();
        /*假设用户输入的用户名密码正确，则放入sessionKey中，对应的value可以
         * 是User对象，这里以字符串"test"代替*/
        session.setAttribute("sessionKey","test");
        mv.setViewName("login");
        return mv;
    }

    @RequestMapping("/view")
    public ModelAndView view(HttpServletRequest request){
        ModelAndView mv = new ModelAndView();
        mv.setViewName("view");
        return mv;
    }

}

package com.mycompany.system.controller;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpSession;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.servlet.ModelAndView;

@Controller
@RequestMapping("/system")
public class systemAction {

@RequestMapping("/login")
public ModelAndView login(HttpServletRequest request){
ModelAndView mv = new ModelAndView();
HttpSession session = request.getSession();
/*假设用户输入的用户名密码正确，则放入sessionKey中，对应的value可以
* 是User对象，这里以字符串"test"代替*/
session.setAttribute("sessionKey","test");
mv.setViewName("login");
return mv;
}

@RequestMapping("/view")
public ModelAndView view(HttpServletRequest request){
ModelAndView mv = new ModelAndView();
mv.setViewName("view");
return mv;
}

}

Constant.java:

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package com.mycompany.mvc.utils;

public class Constant {

    public static final String SESSIONKEY = "sessionKey";

}

package com.mycompany.mvc.utils;

public class Constant {

public static final String SESSIONKEY = "sessionKey";

}

6.拦截器(interceptor)

6.1 拦截器这个要详细讲述一下了，上一篇文章说到，Spring的配置文件应该扫描service层及以下，SpringMvc的配置文件应该扫描controller层；我们在service层如果想做日志的话，可以使用spring
aop特性，在spring.xml中配置aspect即可，那么如果想在controller层做日志，相应地，在SpringMvc.xml中应该怎么配置呢？

这个时候就需要拦截器，它其实也是一种aop的实现(aop本身是一种思想)，而且这种实现本质上和aspect是一样的，只是做了更多的事情，我们当然可以在SpringMvc.xml中也配置aspect，不过现在有一个更好的实现，为什么不用呢。

关于拦截器细节，可以参考这篇文章：http://elim.iteye.com/blog/1750680

6.2 拦截器的实际应用

6.2.1 可以全局做日志

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package com.mycompany.mvc.interceptor;

import java.lang.reflect.Method;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.springframework.web.method.HandlerMethod;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;
/**@Description
* logInterceptor公共拦截器，做日志记录
*/
public class logInterceptor implements HandlerInterceptor{

    @Override
    public void afterCompletion(HttpServletRequest arg0, HttpServletResponse arg1, Object arg2, Exception arg3)
            throws Exception {
        /*做一些清理工作*/
    }

    @Override
    public void postHandle(HttpServletRequest arg0, HttpServletResponse arg1, Object arg2, ModelAndView arg3)
            throws Exception {
        System.out.println("logInterceptor.postHandle()---view Name:"+arg3.getViewName());
    }

    @Override
    public boolean preHandle(HttpServletRequest arg0, HttpServletResponse arg1, Object arg2) throws Exception {
        /*取得调用的controller方法等*/
        if(arg2 instanceof HandlerMethod){
            HandlerMethod hMethod = (HandlerMethod)arg2;
            Method method = hMethod.getMethod();
            System.out.println("logInterceptor.preHandle()--method Name:"+method.getName());
        }
        return true;
    }

}

package com.mycompany.mvc.interceptor;

import java.lang.reflect.Method;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.springframework.web.method.HandlerMethod;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;
/**@Description
* logInterceptor公共拦截器，做日志记录
*/
public class logInterceptor implements HandlerInterceptor{

@Override
public void afterCompletion(HttpServletRequest arg0, HttpServletResponse arg1, Object arg2, Exception arg3)
throws Exception {
/*做一些清理工作*/
}

@Override
public void postHandle(HttpServletRequest arg0, HttpServletResponse arg1, Object arg2, ModelAndView arg3)
throws Exception {
System.out.println("logInterceptor.postHandle()---view Name:"+arg3.getViewName());
}

@Override
public boolean preHandle(HttpServletRequest arg0, HttpServletResponse arg1, Object arg2) throws Exception {
/*取得调用的controller方法等*/
if(arg2 instanceof HandlerMethod){
HandlerMethod hMethod = (HandlerMethod)arg2;
Method method = hMethod.getMethod();
System.out.println("logInterceptor.preHandle()--method Name:"+method.getName());
}
return true;
}

}

6.2.2 记录部分调用的时间

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package com.mycompany.mvc.interceptor;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;
/**@Description
* 登陆时间拦截器，记录用户登录时间
* */
public class timeInterceptor implements HandlerInterceptor{

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler)
            throws Exception {
        return true;
    }

    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler,
            ModelAndView modelAndView) throws Exception {
        System.out.println("timeInterceptor.postHandle()--time:"+System.currentTimeMillis());
    }

    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex)
            throws Exception {
    }

}

package com.mycompany.mvc.interceptor;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;
/**@Description
* 登陆时间拦截器，记录用户登录时间
* */
public class timeInterceptor implements HandlerInterceptor{

@Override
public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler)
throws Exception {
return true;
}

@Override
public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler,
ModelAndView modelAndView) throws Exception {
System.out.println("timeInterceptor.postHandle()--time:"+System.currentTimeMillis());
}

@Override
public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex)
throws Exception {
}

}

上述两个拦截器功能的配置如下，SpringMvc.xml:

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<mvc:interceptors>
    <bean class="com.mycompany.mvc.interceptor.logInterceptor"></bean>
    <mvc:interceptor>
        <mvc:mapping path="/system/view"/>
        <bean class="com.mycompany.mvc.interceptor.timeInterceptor"></bean>
    </mvc:interceptor>
</mvc:interceptors>

<!-- 	拦截器配置 -->
<mvc:interceptors>
<bean class="com.mycompany.mvc.interceptor.logInterceptor"></bean>
<mvc:interceptor>
<mvc:mapping path="/system/view"/>
<bean class="com.mycompany.mvc.interceptor.timeInterceptor"></bean>
</mvc:interceptor>
</mvc:interceptors>

7.总结

到此，它们之前的区别和使用就总结完了，欢迎一起学习讨论。另外，原计划关于shiro的学习和总结要搁浅一段时间^_^ 未来的两个月会学习总结并发和分布式的相关一二~~

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