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build.gradle文件里配置了Spring Session编译依赖的3个项目： apply from: JAVA_GRADLE
apply from: MAVEN_GRADLE
apply plugin: 'spring-io'
description = "Aggregator for Spring Session and Spring Data Redis"
dependencies {
compile project(':spring-session'),
"org.springframework.data:spring-data-redis:$springDataRedisVersion",
"redis.clients:jedis:$jedisVersion",
"org.apache.commons:commons-pool2:$commonsPoolVersion"
springIoVersions "io.spring.platform:platform-versions:${springIoVersion}@properties"
}于是，真正的Maven依赖改成spring-session-data-redis就OK了： <dependency>
<groupId>org.springframework.session</groupId>
<artifactId>spring-session-data-redis</artifactId>
<version>1.0.1.RELEASE</version>
</dependency>（2）第二步，编写一个配置类，用来启用RedisHttpSession功能，并向Spring容器中注册一个RedisConnectionFactory。 import org.springframework.context.annotation.Bean;
import org.springframework.data.redis.connection.RedisConnectionFactory;
import org.springframework.data.redis.connection.jedis.JedisConnectionFactory;
import org.springframework.session.data.redis.config.annotation.web.http.EnableRedisHttpSession;
@EnableRedisHttpSession(maxInactiveIntervalInSeconds = 7200)
public class RedisHttpSessionConfig {
@Bean
public RedisConnectionFactory connectionFactory() {
JedisConnectionFactory connectionFactory = new JedisConnectionFactory();
connectionFactory.setPort(6379);
connectionFactory.setHostName("10.18.15.190");
return connectionFactory;
}
}（3）第三步，将RedisHttpSessionConfig加入到WebInitializer#getRootConfigClasses()中，让Spring容器加载RedisHttpSessionConfig类。WebInitializer是一个自定义的AbstractAnnotationConfigDispatcherServletInitializer实现类，该类会在Servlet启动时加载（当然也可以采用别的加载方法，比如采用扫描@Configuration注解类的方式等等）。 //该类采用Java Configuration，来代替web.xml
public class WebInitializer extends AbstractAnnotationConfigDispatcherServletInitializer {
@Override
protected Class<?>[] getRootConfigClasses() {
return new Class[]{Config1.class, Config2.class, RedisHttpSessionConfig.class};
}
//......
}（4）第四步，编写一个一个AbstractHttpSessionApplicationInitializer实现类，用于向Servlet容器中添加springSessionRepositoryFilter。 import org.springframework.session.web.context.AbstractHttpSessionApplicationInitializer;
public class SpringSessionInitializer extends AbstractHttpSessionApplicationInitializer {
}4. Spring Session原理（1）前面集成spring-sesion的第二步中，编写了一个配置类RedisHttpSessionConfig，它包含注解@EnableRedisHttpSession，并通过@Bean注解注册了一个RedisConnectionFactory到Spring容器中。 而@EnableRedisHttpSession注解通过Import，引入了RedisHttpSessionConfiguration配置类。该配置类通过@Bean注解，向Spring容器中注册了一个SessionRepositoryFilter（SessionRepositoryFilter的依赖关系：SessionRepositoryFilter --> SessionRepository --> RedisTemplate --> RedisConnectionFactory）。 package org.springframework.session.data.redis.config.annotation.web.http;
@Configuration
@EnableScheduling
public class RedisHttpSessionConfiguration implements ImportAware, BeanClassLoaderAware {
//......
@Bean
public RedisTemplate<String,ExpiringSession> sessionRedisTemplate(RedisConnectionFactory connectionFactory) {
//......
return template;
}
@Bean
public RedisOperationsSessionRepository sessionRepository(RedisTemplate<String, ExpiringSession> sessionRedisTemplate) {
//......
return sessionRepository;
}
@Bean
public <S extends ExpiringSession> SessionRepositoryFilter<? extends ExpiringSession> springSessionRepositoryFilter(SessionRepository<S> sessionRepository, ServletContext servletContext) {
//......
return sessionRepositoryFilter;
}
//......
}（2）集成spring-sesion的第四步中，我们编写了一个SpringSessionInitializer 类，它继承自AbstractHttpSessionApplicationInitializer。该类不需要重载或实现任何方法，它的作用是在Servlet容器初始化时，从Spring容器中获取一个默认名叫sessionRepositoryFilter的过滤器类（之前没有注册的话这里找不到会报错），并添加到Servlet过滤器链中。 package org.springframework.session.web.context;
/**
* Registers the {@link DelegatingFilterProxy} to use the
* springSessionRepositoryFilter before any other registered {@link Filter}.
*
* ......
*/
@Order(100)
public abstract class AbstractHttpSessionApplicationInitializer implements WebApplicationInitializer {
private static final String SERVLET_CONTEXT_PREFIX = "org.springframework.web.servlet.FrameworkServlet.CONTEXT.";
public static final String DEFAULT_FILTER_NAME = "springSessionRepositoryFilter";
//......
public void onStartup(ServletContext servletContext)
throws ServletException {
beforeSessionRepositoryFilter(servletContext);
if(configurationClasses != null) {
AnnotationConfigWebApplicationContext rootAppContext = new AnnotationConfigWebApplicationContext();
rootAppContext.register(configurationClasses);
servletContext.addListener(new ContextLoaderListener(rootAppContext));
}
insertSessionRepositoryFilter(servletContext);//注册一个SessionRepositoryFilter
afterSessionRepositoryFilter(servletContext);
}
/**
* Registers the springSessionRepositoryFilter
* @param servletContext the {@link ServletContext}
*/
private void insertSessionRepositoryFilter(ServletContext servletContext) {
String filterName = DEFAULT_FILTER_NAME;//默认名字是springSessionRepositoryFilter
DelegatingFilterProxy springSessionRepositoryFilter = new DelegatingFilterProxy(filterName);//该Filter代理会在初始化时从Spring容器中查找springSessionRepositoryFilter，之后实际会使用SessionRepositoryFilter进行doFilter操作
String contextAttribute = getWebApplicationContextAttribute();
if(contextAttribute != null) {
springSessionRepositoryFilter.setContextAttribute(contextAttribute);
}
registerFilter(servletContext, true, filterName, springSessionRepositoryFilter);
}
//......
}SessionRepositoryFilter是一个优先级最高的javax.servlet.Filter，它使用了一个SessionRepositoryRequestWrapper类接管了Http Session的创建和管理工作。 注意下面给出的是简化过的示例代码，与spring-session项目的源代码有所差异。 @Order(SessionRepositoryFilter.DEFAULT_ORDER)
public class SessionRepositoryFilter implements Filter {
public doFilter(ServletRequest request, ServletResponse response, FilterChain chain) {
HttpServletRequest httpRequest = (HttpServletRequest) request;
SessionRepositoryRequestWrapper customRequest =
new SessionRepositoryRequestWrapper(httpRequest);
chain.doFilter(customRequest, response, chain);
}
// ...
}public class SessionRepositoryRequestWrapper extends HttpServletRequestWrapper {
public SessionRepositoryRequestWrapper(HttpServletRequest original) {
super(original);
}
public HttpSession getSession() {
return getSession(true);
}
public HttpSession getSession(boolean createNew) {
// create an HttpSession implementation from Spring Session
}
// ... other methods delegate to the original HttpServletRequest ...
}（3）好了，剩下的问题就是，如何在Servlet容器启动时，加载下面两个类。幸运的是，这两个类由于都实现了WebApplicationInitializer接口，会被自动加载。
在Servlet3.0规范中，Servlet容器启动时会自动扫描javax.servlet.ServletContainerInitializer的实现类，在实现类中我们可以定制需要加载的类。在spring-web项目中，有一个ServletContainerInitializer实现类SpringServletContainerInitializer，它通过注解@HandlesTypes(WebApplicationInitializer.class)，让Servlet容器在启动该类时，会自动寻找所有的WebApplicationInitializer实现类。 package org.springframework.web;
@HandlesTypes(WebApplicationInitializer.class)
public class SpringServletContainerInitializer implements ServletContainerInitializer {
/**
* Delegate the {@code ServletContext} to any {@link WebApplicationInitializer}
* implementations present on the application classpath.
*
* <p>Because this class declares @{@code HandlesTypes(WebApplicationInitializer.class)},
* Servlet 3.0+ containers will automatically scan the classpath for implementations
* of Spring's {@code WebApplicationInitializer} interface and provide the set of all
* such types to the {@code webAppInitializerClasses} parameter of this method.
*
* <p>If no {@code WebApplicationInitializer} implementations are found on the
* classpath, this method is effectively a no-op. An INFO-level log message will be
* issued notifying the user that the {@code ServletContainerInitializer} has indeed
* been invoked but that no {@code WebApplicationInitializer} implementations were
* found.
*
* <p>Assuming that one or more {@code WebApplicationInitializer} types are detected,
* they will be instantiated (and <em>sorted</em> if the @{@link
* org.springframework.core.annotation.Order @Order} annotation is present or
* the {@link org.springframework.core.Ordered Ordered} interface has been
* implemented). Then the {@link WebApplicationInitializer#onStartup(ServletContext)}
* method will be invoked on each instance, delegating the {@code ServletContext} such
* that each instance may register and configure servlets such as Spring's
* {@code DispatcherServlet}, listeners such as Spring's {@code ContextLoaderListener},
* or any other Servlet API componentry such as filters.
*
* @param webAppInitializerClasses all implementations of
* {@link WebApplicationInitializer} found on the application classpath
* @param servletContext the servlet context to be initialized
* @see WebApplicationInitializer#onStartup(ServletContext)
* @see AnnotationAwareOrderComparator
*/
@Override
public void onStartup(Set<Class<?>> webAppInitializerClasses, ServletContext servletContext)
throws ServletException {
//......
}
}5. 如何在Redis中查看Session数据？（1）Http Session数据在Redis中是以Hash结构存储的。 （2）可以看到，还有一个key="spring:session:expirations:1431577740000"的数据，是以Set结构保存的。这个值记录了所有session数据应该被删除的时间（即最新的一个session数据过期的时间）。 127.0.0.1:6379> keys * 1) "spring:session:expirations:1431577740000" 2) "spring:session:sessions:e2cef3ae-c8ea-4346-ba6b-9b3b26eee578" 127.0.0.1:6379> type spring:session:sessions:e2cef3ae-c8ea-4346-ba6b-9b3b26eee578 hash 127.0.0.1:6379> type spring:session:expirations:1431577740000 set 127.0.0.1:6379> keys * 1) "spring:session:expirations:1431527520000" 2) "spring:session:sessions:59f3987c-d1e4-44b3-a83a-32079942888b" 3) "spring:session:sessions:11a69da6-138b-42bc-9916-60ae78aa55aa" 4) "spring:session:sessions:0a51e2c2-4a3b-4986-a754-d886d8a5d42d" 5) "spring:session:expirations:1431527460000" 127.0.0.1:6379> hkeys spring:session:sessions:59f3987c-d1e4-44b3-a83a-32079942888b 1) "maxInactiveInterval" 2) "creationTime" 3) "lastAccessedTime" 4) "sessionAttr:attr1" 127.0.0.1:6379> hget spring:session:sessions:59f3987c-d1e4-44b3-a83a-32079942888b sessionAttr:attr1 "\xac\xed\x00\x05sr\x00\x11java.lang.Integer\x12\xe2\xa0\xa4\xf7\x81\x878\x02\x00\x01I\x00\x05valuexr\x00\x10java.lang.Number\x86\xac\x95\x1d\x0b\x94\xe0\x8b\x02\x00\x00xp\x00\x00\x00\x03" 127.0.0.1:6379> hget spring:session:sessions:59f3987c-d1e4-44b3-a83a-32079942888b creationTime "\xac\xed\x00\x05sr\x00\x0ejava.lang.Long;\x8b\xe4\x90\xcc\x8f#\xdf\x02\x00\x01J\x00\x05valuexr\x00\x10java.lang.Number\x86\xac\x95\x1d\x0b\x94\xe0\x8b\x02\x00\x00xp\x00\x00\x01MM\x94(\xec" 6.参考文章Spring Session 1.01 Reference spring session入门 集群session共享机制 |
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来自： instl > 《software engineering》
