HBase协处理器

2019-04-08 17:26:21 +08:00
parent 784a420f58
commit d7c4b2ad2b
13 changed files with 568 additions and 1 deletions
--- a/code/Hbase/hbase-observer-coprocessor/src/main/java/com/heibaiying/AppendRegionObserver.java
+++ b/code/Hbase/hbase-observer-coprocessor/src/main/java/com/heibaiying/AppendRegionObserver.java
@@ -0,0 +1,51 @@
+package com.heibaiying;
+
+import org.apache.hadoop.hbase.Cell;
+import org.apache.hadoop.hbase.CellUtil;
+import org.apache.hadoop.hbase.client.Durability;
+import org.apache.hadoop.hbase.client.Get;
+import org.apache.hadoop.hbase.client.Put;
+import org.apache.hadoop.hbase.client.Result;
+import org.apache.hadoop.hbase.coprocessor.BaseRegionObserver;
+import org.apache.hadoop.hbase.coprocessor.ObserverContext;
+import org.apache.hadoop.hbase.coprocessor.RegionCoprocessorEnvironment;
+import org.apache.hadoop.hbase.regionserver.wal.WALEdit;
+import org.apache.hadoop.hbase.util.Bytes;
+
+import java.io.IOException;
+import java.util.List;
+
+/**
+ * 对相同的article:content执行put命令时，将新插入的内容添加到原有内容的末尾
+ */
+public class AppendRegionObserver extends BaseRegionObserver {
+
+    private byte[] columnFamily = Bytes.toBytes("article");
+    private byte[] qualifier = Bytes.toBytes("content");
+
+    @Override
+    public void prePut(ObserverContext<RegionCoprocessorEnvironment> e, Put put, WALEdit edit,
+                       Durability durability) throws IOException {
+        if (put.has(columnFamily, qualifier)) {
+            // 遍历查询结果，获取指定列的原值
+            Result rs = e.getEnvironment().getRegion().get(new Get(put.getRow()));
+            String oldValue = "";
+            for (Cell cell : rs.rawCells())
+                if (CellUtil.matchingColumn(cell, columnFamily, qualifier)) {
+                    oldValue = Bytes.toString(CellUtil.cloneValue(cell));
+                }
+
+            // 获取指定列新插入的值
+            List<Cell> cells = put.get(columnFamily, qualifier);
+            String newValue = "";
+            for (Cell cell : cells) {
+                if (CellUtil.matchingColumn(cell, columnFamily, qualifier)) {
+                    newValue = Bytes.toString(CellUtil.cloneValue(cell));
+                }
+            }
+
+            // Append 操作
+            put.addColumn(columnFamily, qualifier, Bytes.toBytes(oldValue + newValue));
+        }
+    }
+}