HBASE-28191 Meta browser can happen NPE when server or targetServer o…

…f region is null (#5508)

Signed-off-by: Wellington Chevreuil <wchevreuil@apache.org>
Signed-off-by: Duo Zhang <zhangduo@apache.org>

hbase-server/src/main/resources/hbase-webapps/master/table.jsp

@@ -562,12 +562,13 @@
       final RegionInfo regionInfo = regionReplicaInfo.getRegionInfo();
       final ServerName serverName = regionReplicaInfo.getServerName();
       final RegionState.State regionState = regionReplicaInfo.getRegionState();
-      final int rsPort = master.getRegionServerInfoPort(serverName);
 
       final long seqNum = regionReplicaInfo.getSeqNum();
 
       final String regionSpanFormat = "<span title=" + HConstants.CATALOG_FAMILY_STR + ":%s>%s</span>";
-      final String targetServerName = regionReplicaInfo.getTargetServerName().toString();
+      final String targetServerName = regionReplicaInfo.getTargetServerName() != null
+        ? regionReplicaInfo.getTargetServerName().toString()
+        : "";
       final Map<String, RegionInfo> mergeRegions = regionReplicaInfo.getMergeRegionInfo();
       final String mergeRegionNames = (mergeRegions == null) ? "" :
         mergeRegions.entrySet().stream()
@@ -585,7 +586,7 @@
       <td title="endKey"><%= endKeyDisplay %></td>
       <td title="replicaId"><%= replicaIdDisplay %></td>
       <td title="regionState"><%= regionStateDisplay %></td>
-      <td title="<%= serverColumnName + "," + startCodeColumnName %>"><%= buildRegionLink(serverName, rsPort, regionInfo, regionState) %></td>
+      <td title="<%= serverColumnName + "," + startCodeColumnName %>"><%= serverName != null ? buildRegionLink(serverName, master.getRegionServerInfoPort(serverName), regionInfo, regionState) : "" %></td>
       <td title="<%= seqNumColumnName %>"><%= seqNum %></td>
       <td title="<%= serverNameColumnName %>"><%= targetServerName %></td>
       <td><%= mergeRegionNames %></td>