更新hbase

code/src/main/java/com/raorao/java/thread/TopN.java

@@ -0,0 +1,35 @@
+package com.raorao.java.thread;
+
+import java.util.Iterator;
+import java.util.PriorityQueue;
+
+/**
+ * 得到TopN的方法（使用优先队列）.
+ *
+ * @author Xiong Raorao
+ * @since 2018-08-03-10:18
+ */
+public class TopN {
+
+  public static void main(String[] args) {
+    PriorityQueue<Integer> p = new PriorityQueue<>(5);
+    int[] aa = new int[] {1, 2, 3, 4, 77, 22, 42, 35, 8, 12};
+    for (int i : aa) {
+      if (p.size() < 5) {
+        p.offer(i);
+      } else {
+        if (i < p.peek()) {
+          // do nothing
+        } else {
+          p.offer(i);
+          p.poll();
+        }
+      }
+    }
+
+    Iterator<Integer> iterator = p.iterator();
+    while (iterator.hasNext()) {
+      System.out.println(iterator.next());
+    }
+  }
+}