avoid introspecting the resultset

Author: emacarron

src/main/java/org/apache/ibatis/executor/resultset/FastResultSetHandler.java

@@ -419,8 +419,7 @@ protected Object createPrimitiveResultObject(ResultSet rs, ResultMap resultMap,
       final ResultMapping mapping = resultMappingList.get(0);
       columnName = prependPrefix(mapping.getColumn(), columnPrefix);
     } else {
-      final ResultSetMetaData rsmd = rs.getMetaData();
-      columnName = configuration.isUseColumnLabel() ? rsmd.getColumnLabel(1) : rsmd.getColumnName(1);
+      columnName = resultColumnCache.getColumnNames().get(0);
     }
     final TypeHandler<?> typeHandler = resultColumnCache.getTypeHandler(resultType, columnName);
     return typeHandler.getResult(rs, columnName);
@@ -587,6 +586,10 @@ protected ResultColumnCache(ResultSetMetaData metaData, Configuration configurat
       }
     }
 
+    protected List<String> getColumnNames() {
+      return this.columnNames;
+    }
+    
     protected JdbcType getJdbcType(String columnName) {
       final int index = columnNames.indexOf(columnName);
       return jdbcTypes.get(index);

src/main/java/org/apache/ibatis/executor/resultset/NestedResultSetHandler.java

@@ -16,7 +16,6 @@
 package org.apache.ibatis.executor.resultset;
 
 import java.sql.ResultSet;
-import java.sql.ResultSetMetaData;
 import java.sql.SQLException;
 import java.util.HashMap;
 import java.util.List;
@@ -247,7 +246,7 @@ private CacheKey createRowKey(ResultMap resultMap, ResultSet rs, String columnPr
     List<ResultMapping> resultMappings = getResultMappingsForRowKey(resultMap);
     if (resultMappings.size() == 0) {
       if (Map.class.isAssignableFrom(resultMap.getType())) {
-        createRowKeyForMap(rs, cacheKey);
+        createRowKeyForMap(rs, cacheKey, resultColumnCache);
       } else {
         createRowKeyForUnmappedProperties(resultMap, rs, cacheKey, columnPrefix, resultColumnCache);
       }
@@ -322,16 +321,14 @@ private void createRowKeyForUnmappedProperties(ResultMap resultMap, ResultSet rs
     }
   }
 
-  private void createRowKeyForMap(ResultSet rs, CacheKey cacheKey) throws SQLException {
-    final ResultSetMetaData rsmd = rs.getMetaData();
-    final int columnCount = rsmd.getColumnCount();
-    for (int i = 1; i <= columnCount; i++) {
-      final String columnName = configuration.isUseColumnLabel() ? rsmd.getColumnLabel(i) : rsmd.getColumnName(i);
+  private void createRowKeyForMap(ResultSet rs, CacheKey cacheKey, ResultColumnCache resultColumnCache) throws SQLException {
+    List<String> columnNames = resultColumnCache.getColumnNames();
+    for (String columnName : columnNames) {
       final String value = rs.getString(columnName);
       if (value != null) {
         cacheKey.update(columnName);
         cacheKey.update(value);
-      }
+      }      
     }
   }