issue #69 添加Session的支持，添加测试用例

weixin-java-common/src/main/java/me/chanjar/weixin/common/session/InternalSessionManager.java

@@ -2,6 +2,19 @@ package me.chanjar.weixin.common.session;
 
 public interface InternalSessionManager {
 
+  /**
+   * Return the active Session, associated with this Manager, with the
+   * specified session id (if any); otherwise return <code>null</code>.
+   *
+   * @param id The session id for the session to be returned
+   *
+   * @exception IllegalStateException if a new session cannot be
+   *  instantiated for any reason
+   * @exception java.io.IOException if an input/output error occurs while
+   *  processing this request
+   */
+  InternalSession findSession(String id);
+
   /**
    * Construct and return a new session object, based on the default
    * settings specified by this Manager's properties.  The session
@@ -68,7 +81,33 @@ public interface InternalSessionManager {
    */
   void setMaxInactiveInterval(int interval);
 
+  /**
+   * <pre>
+   * Set the manager checks frequency.
+   * 设置每尝试多少次清理过期session，才真的会执行一次清理动作
+   * 要和{@link #setBackgroundProcessorDelay(int)}联合起来看
+   * 如果把这个数字设置为6（默认），那么就是说manager要等待 6 * backgroundProcessorDay的时间才会清理过期session
+   * </pre>
+   * @param processExpiresFrequency the new manager checks frequency
+   */
   void setProcessExpiresFrequency(int processExpiresFrequency);
 
+  /**
+   * <pre>
+   * Set the manager background processor delay
+   * 设置manager sleep几秒，尝试执行一次background操作（清理过期session）
+   * </pre>
+   * @param backgroundProcessorDelay
+   */
   void setBackgroundProcessorDelay(int backgroundProcessorDelay);
+
+
+  /**
+   * Set the maximum number of active Sessions allowed, or -1 for
+   * no limit.
+   * 设置最大活跃session数，默认无限
+   * @param max The new maximum number of sessions
+   */
+  void setMaxActiveSessions(int max);
+
 }

weixin-java-common/src/main/java/me/chanjar/weixin/common/session/StandardSession.java

@@ -6,7 +6,7 @@ import java.util.*;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.atomic.AtomicInteger;
 
-public class SessionImpl implements WxSession, InternalSession {
+public class StandardSession implements WxSession, InternalSession {
 
   /**
    * The string manager for this package.
@@ -129,7 +129,7 @@ public class SessionImpl implements WxSession, InternalSession {
    * The facade associated with this session.  NOTE:  This value is not
    * included in the serialized version of this object.
    */
-  protected transient InternalSessionFacade facade = null;
+  protected transient StandardSessionFacade facade = null;
 
   /**
    * The access count for this session.
@@ -137,7 +137,7 @@ public class SessionImpl implements WxSession, InternalSession {
   protected transient AtomicInteger accessCount = null;
 
 
-  public SessionImpl(InternalSessionManager manager) {
+  public StandardSession(InternalSessionManager manager) {
     this.manager = manager;
     this.accessCount = new AtomicInteger();
   }
@@ -147,7 +147,7 @@ public class SessionImpl implements WxSession, InternalSession {
   public WxSession getSession() {
 
     if (facade == null){
-      facade = new InternalSessionFacade(this);
+      facade = new StandardSessionFacade(this);
     }
     return (facade);
 
@@ -281,7 +281,6 @@ public class SessionImpl implements WxSession, InternalSession {
 
   @Override
   public void setMaxInactiveInterval(int interval) {
-    int oldMaxInactiveInterval = this.maxInactiveInterval;
     this.maxInactiveInterval = interval;
   }
 
@@ -311,9 +310,9 @@ public class SessionImpl implements WxSession, InternalSession {
   @Override
   public boolean equals(Object o) {
     if (this == o) return true;
-    if (!(o instanceof SessionImpl)) return false;
+    if (!(o instanceof StandardSession)) return false;
 
-    SessionImpl session = (SessionImpl) o;
+    StandardSession session = (StandardSession) o;
 
     if (creationTime != session.creationTime) return false;
     if (expiring != session.expiring) return false;

weixin-java-common/src/main/java/me/chanjar/weixin/common/session/StandardSessionFacade.java

@@ -2,17 +2,21 @@ package me.chanjar.weixin.common.session;
 
 import java.util.Enumeration;
 
-public class InternalSessionFacade implements WxSession {
+public class StandardSessionFacade implements WxSession {
 
   /**
    * Wrapped session object.
    */
   private WxSession session = null;
 
-  public InternalSessionFacade(WxSession session) {
+  public StandardSessionFacade(StandardSession session) {
     this.session = session;
   }
 
+  public InternalSession getInternalSession() {
+    return (InternalSession) session;
+  }
+
   @Override
   public Object getAttribute(String name) {
     return session.getAttribute(name);
@@ -37,4 +41,5 @@ public class InternalSessionFacade implements WxSession {
   public void invalidate() {
     session.invalidate();
   }
+
 }

weixin-java-common/src/main/java/me/chanjar/weixin/common/session/StandardSessionManager.java

@@ -8,9 +8,12 @@ import java.util.Map;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.atomic.AtomicBoolean;
 
-public class InMemorySessionManager implements WxSessionManager, InternalSessionManager {
+/**
+ * 基于内存的session manager
+ */
+public class StandardSessionManager implements WxSessionManager, InternalSessionManager {
 
-  protected final Logger log = LoggerFactory.getLogger(InMemorySessionManager.class);
+  protected final Logger log = LoggerFactory.getLogger(StandardSessionManager.class);
 
   protected static final StringManager sm =
       StringManager.getManager(Constants.Package);
@@ -128,18 +131,9 @@ public class InMemorySessionManager implements WxSessionManager, InternalSession
   }
 
 
-  /**
-   * Return the active Session, associated with this Manager, with the
-   * specified session id (if any); otherwise return <code>null</code>.
-   *
-   * @param id The session id for the session to be returned
-   *
-   * @exception IllegalStateException if a new session cannot be
-   *  instantiated for any reason
-   * @exception java.io.IOException if an input/output error occurs while
-   *  processing this request
-   */
-  protected InternalSession findSession(String id) {
+
+  @Override
+  public InternalSession findSession(String id) {
 
     if (id == null)
       return (null);
@@ -189,12 +183,11 @@ public class InMemorySessionManager implements WxSessionManager, InternalSession
     return (getNewSession());
   }
 
-
   /**
    * Get new session class to be used in the doLoad() method.
    */
   protected InternalSession getNewSession() {
-    return new SessionImpl(this);
+    return new StandardSession(this);
   }
 
 
@@ -312,4 +305,17 @@ public class InMemorySessionManager implements WxSessionManager, InternalSession
 
   }
 
+  /**
+   * Set the maximum number of active Sessions allowed, or -1 for
+   * no limit.
+   *
+   * @param max The new maximum number of sessions
+   */
+  @Override
+  public void setMaxActiveSessions(int max) {
+
+    this.maxActiveSessions = max;
+
+  }
+
 }

weixin-java-common/src/main/java/me/chanjar/weixin/common/util/WxMessageInMemoryDuplicateChecker.java

@@ -82,6 +82,9 @@ public class WxMessageInMemoryDuplicateChecker implements WxMessageDuplicateChec
 
   @Override
   public boolean isDuplicate(Long wxMsgId) {
+    if (wxMsgId == null) {
+      return false;
+    }
     checkBackgroundProcessStarted();
     Long timestamp = msgId2Timestamp.putIfAbsent(wxMsgId, System.currentTimeMillis());
     if (timestamp == null) {