issue #66

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

@@ -0,0 +1,18 @@
+package me.chanjar.weixin.common.util;
+
+/**
+ * <pre>
+ * 消息重复检查器
+ * 微信服务器在五秒内收不到响应会断掉连接，并且重新发起请求，总共重试三次
+ * </pre>
+ */
+public interface WxMsgIdDuplicateChecker {
+
+  /**
+   * 检查消息ID是否重复
+   * @param wxMsgId
+   * @return 如果是重复消息，返回true，否则返回false
+   */
+  public boolean isDuplicate(Long wxMsgId);
+
+}

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

@@ -0,0 +1,84 @@
+package me.chanjar.weixin.common.util;
+
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+
+/**
+ * <pre>
+ * 默认消息重复检查器
+ * 将每个消息id保存在内存里，每隔5秒清理已经过期的消息id，每个消息id的过期时间是15秒
+ * </pre>
+ */
+public class WxMsgIdInMemoryDuplicateChecker implements WxMsgIdDuplicateChecker {
+
+  /**
+   * 一个消息ID在内存的过期时间：15秒
+   */
+  private final Long TIME_TO_LIVE;
+
+  /**
+   * 每隔多少周期检查消息ID是否过期：5秒
+   */
+  private final Long CLEAR_PERIOD;
+
+  private final ConcurrentHashMap<Long, Long> msgId2Timestamp = new ConcurrentHashMap<Long, Long>();
+
+  /**
+   * WxMsgIdInMemoryDuplicateChecker构造函数
+   * <pre>
+   * 一个消息ID在内存的过期时间：15秒
+   * 每隔多少周期检查消息ID是否过期：5秒
+   * </pre>
+   */
+  public WxMsgIdInMemoryDuplicateChecker() {
+    this.TIME_TO_LIVE = 15 * 1000l;
+    this.CLEAR_PERIOD = 5 * 1000l;
+    this.start();
+  }
+
+  /**
+   * WxMsgIdInMemoryDuplicateChecker构造函数
+   * @param timeToLive 一个消息ID在内存的过期时间：毫秒
+   * @param clearPeriod 每隔多少周期检查消息ID是否过期：毫秒
+   */
+  public WxMsgIdInMemoryDuplicateChecker(Long timeToLive, Long clearPeriod) {
+    this.TIME_TO_LIVE = timeToLive;
+    this.CLEAR_PERIOD = clearPeriod;
+    this.start();
+  }
+
+  private void start() {
+    Thread t = new Thread(new Runnable() {
+      @Override
+      public void run() {
+        try {
+          while (true) {
+            Thread.sleep(CLEAR_PERIOD);
+            Long now = System.currentTimeMillis();
+            for (Map.Entry<Long, Long> entry : msgId2Timestamp.entrySet()) {
+              if (now - entry.getValue() > TIME_TO_LIVE) {
+                msgId2Timestamp.entrySet().remove(entry);
+              }
+            }
+          }
+        } catch (InterruptedException e) {
+          e.printStackTrace();
+        }
+      }
+    });
+    t.setDaemon(true);
+    t.start();
+  }
+
+  @Override
+  public boolean isDuplicate(Long wxMsgId) {
+    Long timestamp = msgId2Timestamp.putIfAbsent(wxMsgId, System.currentTimeMillis());
+    if (timestamp == null) {
+      // 第一次接收到这个消息
+      return false;
+    }
+    return true;
+  }
+
+
+}

weixin-java-common/src/test/java/me/chanjar/weixin/common/util/WxMsgIdInMemoryDuplicateCheckerTest.java

@@ -0,0 +1,38 @@
+package me.chanjar.weixin.common.util;
+
+import org.testng.Assert;
+import org.testng.annotations.Test;
+
+/**
+ * Created by qianjia on 15/1/20.
+ */
+@Test
+public class WxMsgIdInMemoryDuplicateCheckerTest {
+
+  public void test() throws InterruptedException {
+    Long[] msgIds = new Long[] { 1l, 2l, 3l, 4l, 5l, 6l, 7l, 8l };
+    WxMsgIdInMemoryDuplicateChecker checker = new WxMsgIdInMemoryDuplicateChecker(2000l, 1000l);
+
+    // 第一次检查
+    for (Long msgId : msgIds) {
+      boolean result = checker.isDuplicate(msgId);
+      Assert.assertFalse(result);
+    }
+
+    // 过1秒再检查
+    Thread.sleep(1000l);
+    for (Long msgId : msgIds) {
+      boolean result = checker.isDuplicate(msgId);
+      Assert.assertTrue(result);
+    }
+
+    // 过1.5秒再检查
+    Thread.sleep(1500l);
+    for (Long msgId : msgIds) {
+      boolean result = checker.isDuplicate(msgId);
+      Assert.assertFalse(result);
+    }
+
+  }
+
+}

weixin-java-common/src/test/resources/testng.xml

@@ -7,6 +7,7 @@
 			<class name="me.chanjar.weixin.common.bean.WxErrorTest" />
             <class name="me.chanjar.weixin.common.bean.WxMenuTest" />
             <class name="me.chanjar.weixin.common.util.crypto.WxCryptUtilTest" />
+            <class name="me.chanjar.weixin.common.util.WxMsgIdInMemoryDuplicateCheckerTest" />
         </classes>
 	</test>
 </suite>