SPRING-SESSION

HTTP SESSION的管理通常是由容器来做，但如果是在PAAS环境下，服务器不能做变更，则需要由WEB应用来做处理HTTP SESSION。

同样，如果是分布式的环境下，SESSION的管理也会带来性能问题。

SPRING推出了处理SESSION的框架：SPRING-SESSION。


SPRING会重写HTTP SESSION的那一套，使用SESSION也同样还是用

req.getSession().setAttribute(attributeName, attributeValue);

此框架使用REDIS作为HTTP SESSION的持久化容器。此框架只对使用的当前WEB应用下的HTTP SESSION进行集中管理，同一WEB容器下的其他WEB应用还是会使用容器的SESSION管理那一套。

pom.xml

< project  xmlns ="http://maven.apache.org/POM/4.0.0"  xmlns:xsi ="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation ="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd" >
     < modelVersion >4.0.0 </ modelVersion >
     < groupId >com.paul </ groupId >
     < artifactId >spring-session </ artifactId >
     < packaging >war </ packaging >
         < version >1.0 </ version >
     < repositories >
         < repository >
             < id >spring-snapshot </ id >
             < url >https://repo.spring.io/libs-milestone </ url >
         </ repository >
         < repository >
             < id >clojars.org </ id >
             < url >http://clojars.org/repo </ url >
         </ repository >
     </ repositories >
     < dependencies >
         < dependency >
             < groupId >org.springframework.session </ groupId >
             < artifactId >spring-session </ artifactId >
             < version >1.0.0.RC1 </ version >
         </ dependency >
         < dependency >
             < groupId >org.springframework </ groupId >
             < artifactId >spring-web </ artifactId >
             < version >${spring.version} </ version >
         </ dependency >
         < dependency >
             < groupId >org.springframework.data </ groupId >
             < artifactId >spring-data-redis </ artifactId >
             < version >1.3.0.RELEASE </ version >
         </ dependency >
         < dependency >
             < groupId >redis.clients </ groupId >
             < artifactId >jedis </ artifactId >
             < version >2.4.1 </ version >
         </ dependency >
         < dependency >
             < groupId >org.apache.commons </ groupId >
             < artifactId >commons-pool2 </ artifactId >
             < version >2.2 </ version >
         </ dependency >
         < dependency >
             < groupId >redis.embedded </ groupId >
             < artifactId >embedded-redis </ artifactId >
             < version >0.3 </ version >
         </ dependency >
         < dependency >
             < groupId >javax.servlet </ groupId >
             < artifactId >javax.servlet-api </ artifactId >
             < version >3.1.0 </ version >
             < scope >provided </ scope >
         </ dependency >
         < dependency >
             < groupId >jstl </ groupId >
             < artifactId >jstl </ artifactId >
             < version >1.2 </ version >
         </ dependency >
     </ dependencies >
     < build >
         < plugins >
             < plugin >
                 < groupId >org.apache.tomcat.maven </ groupId >
                 < artifactId >tomcat7-maven-plugin </ artifactId >
                 < version >2.0 </ version >
                 < configuration >
                     < path >/ </ path >
                 </ configuration >
             </ plugin >
             < plugin >
                 < artifactId >maven-compiler-plugin </ artifactId >
                 < version >3.1 </ version >
                 < configuration >
                     < source >1.7 </ source >
                     < target >1.7 </ target >
                 </ configuration >
             </ plugin >
         </ plugins >
     </ build >
     < properties >
         < spring .version >4.1.0.RELEASE </ spring.version >
     </ properties >
</ project >

在ECLIPSE中运行TOMCAT的文件：spring-session-tomcat-run.launch

<? xml version="1.0" encoding="UTF-8" standalone="no" ?>
< launchConfiguration  type ="org.eclipse.m2e.Maven2LaunchConfigurationType" >
< booleanAttribute  key ="M2_DEBUG_OUTPUT"  value ="false" />
< stringAttribute  key ="M2_GOALS"  value ="tomcat7:run" />
< booleanAttribute  key ="M2_NON_RECURSIVE"  value ="false" />
< booleanAttribute  key ="M2_OFFLINE"  value ="false" />
< stringAttribute  key ="M2_PROFILES"  value ="" />
< listAttribute  key ="M2_PROPERTIES" />
< stringAttribute  key ="M2_RUNTIME"  value ="EMBEDDED" />
< booleanAttribute  key ="M2_SKIP_TESTS"  value ="false" />
< intAttribute  key ="M2_THREADS"  value ="1" />
< booleanAttribute  key ="M2_UPDATE_SNAPSHOTS"  value ="false" />
< booleanAttribute  key ="M2_WORKSPACE_RESOLUTION"  value ="false" />
< stringAttribute  key ="org.eclipse.jdt.launching.VM_ARGUMENTS"  value ="-Dspring.profiles.active=dev" />
< stringAttribute  key ="org.eclipse.jdt.launching.WORKING_DIRECTORY"  value ="${workspace_loc:/spring-session}" />
</ launchConfiguration >

启动内置REDIS服务器的文件：EmbeddedRedisConfiguration.java

package com.paul.springsesseion;

import org.springframework.beans.factory.DisposableBean;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

import redis.clients.jedis.Protocol;
import redis.embedded.RedisServer;

/**
 * Runs an embedded Redis instance. This is only necessary since we do not want
 * users to have to setup a Redis instance. In a production environment, this
 * would not be used since a Redis Server would be setup.
 *
 *  @author  Rob Winch
  */
@Configuration
public  class EmbeddedRedisConfiguration {

     @Bean
     public RedisServerBean redisServer() {
         return  new RedisServerBean();
    }

     class RedisServerBean  implements InitializingBean, DisposableBean {
         private RedisServer redisServer;


        @Override
         public  void afterPropertiesSet()  throws Exception {
            redisServer =  new RedisServer(Protocol.DEFAULT_PORT);
            redisServer.start();
        }

        @Override
         public  void destroy()  throws Exception {
             if(redisServer !=  null) {
                redisServer.stop();
            }
        }
    }
}

配置文件：Config.java

package com.paul.springsesseion;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Import;
import org.springframework.data.redis.connection.jedis.JedisConnectionFactory;
import org.springframework.session.data.redis.config.annotation.web.http.EnableRedisHttpSession;

/**
 *  @author  Rob Winch
  */
@Import(EmbeddedRedisConfiguration. class)
@Configuration
@EnableRedisHttpSession
public  class Config {

    @Bean
     public JedisConnectionFactory connectionFactory() {
         return  new JedisConnectionFactory();
    }
}

初始化配置文件：Initializer.java

package com.paul.springsesseion;

import org.springframework.session.web.context.AbstractHttpSessionApplicationInitializer;

/**
 *  @author  Rob Winch
  */
public  class Initializer  extends AbstractHttpSessionApplicationInitializer {

     public Initializer() {
         super(Config. class);
    }
}

存取HTTP SESSION：SessionServlet.java

package com.paul.springsesseion;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

/**
 *  @author  Rob Winch
  */
@WebServlet("/session")
public  class SessionServlet  extends HttpServlet {

    @Override
     protected  void doPost(HttpServletRequest req, HttpServletResponse resp)  throws ServletException, IOException {
        String attributeName = req.getParameter("attributeName");
        String attributeValue = req.getParameter("attributeValue");
        req.getSession().setAttribute(attributeName, attributeValue);
        resp.sendRedirect(req.getContextPath() + "/");
    }

     private  static  final  long serialVersionUID = 2878267318695777395L;
}

页面：index.jsp

<% @ taglib prefix = " c "  uri = " http://java.sun.com/jsp/jstl/core "   %>
<! DOCTYPE html >
< html  lang ="en" >
< head >
     < title >Session Attributes </ title >
     < link  rel ="stylesheet"  href ="assets/bootstrap.min.css" >
     < style  type ="text/css" >
        body  {
            padding :  1em ;
         }
     </ style >
</ head >
< body >
     < div  class ="container" >
         < h1 >Description </ h1 >
         < p >This application demonstrates how to use a Redis instance to back your session. Notice that there is no JSESSIONID cookie. We are also able to customize the way of identifying what the requested session id is. </ p >

         < h1 >Try it </ h1 >

         < form  class ="form-inline"  role ="form"  action ="./session"  method ="post" >
             < label  for ="attributeValue" >Attribute Name </ label >
             < input  id ="attributeValue"  type ="text"  name ="attributeName" />
             < label  for ="attributeValue" >Attribute Value </ label >
             < input  id ="attributeValue"  type ="text"  name ="attributeValue" />
             < input  type ="submit"  value ="Set Attribute" />
         </ form >

         < hr />

         < table  class ="table table-striped" >
             < thead >
             < tr >
                 < th >Attribute Name </ th >
                 < th >Attribute Value </ th >
             </ tr >
             </ thead >
             < tbody >
             < c:forEach  items ="${sessionScope}"  var ="attr" >
                 < tr >
                     < td >< c:out  value ="${attr.key}" /></ td >
                     < td >< c:out  value ="${attr.value}" /></ td >
                 </ tr >
             </ c:forEach >
             </ tbody >
         </ table >
     </ div >
</ body >
</ html >