JdbcTemplate consistently exposes first value of equally named columns

Issue: SPR-16578

spring-jdbc/src/main/java/org/springframework/jdbc/core/ColumnMapRowMapper.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2017 the original author or authors.
+ * Copyright 2002-2018 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -52,13 +52,12 @@ public class ColumnMapRowMapper implements RowMapper<Map<String, Object>> {
 	public Map<String, Object> mapRow(ResultSet rs, int rowNum) throws SQLException {
 		ResultSetMetaData rsmd = rs.getMetaData();
 		int columnCount = rsmd.getColumnCount();
-		Map<String, Object> mapOfColValues = createColumnMap(columnCount);
+		Map<String, Object> mapOfColumnValues = createColumnMap(columnCount);
 		for (int i = 1; i <= columnCount; i++) {
-			String key = getColumnKey(JdbcUtils.lookupColumnName(rsmd, i));
-			Object obj = getColumnValue(rs, i);
-			mapOfColValues.put(key, obj);
+			String column = JdbcUtils.lookupColumnName(rsmd, i);
+			mapOfColumnValues.putIfAbsent(getColumnKey(column), getColumnValue(rs, i));
 		}
-		return mapOfColValues;
+		return mapOfColumnValues;
 	}
 
 	/**

spring-jdbc/src/main/java/org/springframework/jdbc/core/metadata/TableMetaDataContext.java

@@ -253,7 +253,7 @@ public class TableMetaDataContext {
 					for (Map.Entry<String, ?> entry : inParameters.entrySet()) {
 						if (column.equalsIgnoreCase(entry.getKey())) {
 							value = entry.getValue();
-							// TODO: break;
+							break;
 						}
 					}
 				}

spring-jdbc/src/test/java/org/springframework/jdbc/core/JdbcTemplateTests.java

@@ -22,12 +22,14 @@ import java.sql.Connection;
 import java.sql.DatabaseMetaData;
 import java.sql.PreparedStatement;
 import java.sql.ResultSet;
+import java.sql.ResultSetMetaData;
 import java.sql.SQLException;
 import java.sql.SQLWarning;
 import java.sql.Statement;
 import java.sql.Types;
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.Collections;
 import java.util.LinkedList;
 import java.util.List;
 import java.util.Map;
@@ -704,10 +706,10 @@ public class JdbcTemplateTests {
 	@Test
 	public void testBatchUpdateWithListOfObjectArrays() throws Exception {
 		final String sql = "UPDATE NOSUCHTABLE SET DATE_DISPATCHED = SYSDATE WHERE ID = ?";
-		final List<Object[]> ids = new ArrayList<>();
+		final List<Object[]> ids = new ArrayList<>(2);
 		ids.add(new Object[] {100});
 		ids.add(new Object[] {200});
-		final int[] rowsAffected = new int[] { 1, 2 };
+		final int[] rowsAffected = new int[] {1, 2};
 
 		given(this.preparedStatement.executeBatch()).willReturn(rowsAffected);
 		mockDatabaseMetaData(true);
@@ -730,11 +732,11 @@ public class JdbcTemplateTests {
 	@Test
 	public void testBatchUpdateWithListOfObjectArraysPlusTypeInfo() throws Exception {
 		final String sql = "UPDATE NOSUCHTABLE SET DATE_DISPATCHED = SYSDATE WHERE ID = ?";
-		final List<Object[]> ids = new ArrayList<>();
+		final List<Object[]> ids = new ArrayList<>(2);
 		ids.add(new Object[] {100});
 		ids.add(new Object[] {200});
 		final int[] sqlTypes = new int[] {Types.NUMERIC};
-		final int[] rowsAffected = new int[] { 1, 2 };
+		final int[] rowsAffected = new int[] {1, 2};
 
 		given(this.preparedStatement.executeBatch()).willReturn(rowsAffected);
 		mockDatabaseMetaData(true);
@@ -1070,14 +1072,13 @@ public class JdbcTemplateTests {
 		given(this.callableStatement.execute()).willReturn(true);
 		given(this.callableStatement.getUpdateCount()).willReturn(-1);
 
-		List<SqlParameter> params = new ArrayList<>();
-		params.add(new SqlReturnResultSet("", (RowCallbackHandler) rs -> {
+		SqlParameter param = new SqlReturnResultSet("", (RowCallbackHandler) rs -> {
 			throw new InvalidDataAccessApiUsageException("");
-		}));
+		});
 
 		this.thrown.expect(InvalidDataAccessApiUsageException.class);
 		try {
-			this.template.call(conn -> conn.prepareCall("my query"), params);
+			this.template.call(conn -> conn.prepareCall("my query"), Collections.singletonList(param));
 		}
 		finally {
 			verify(this.resultSet).close();
@@ -1099,10 +1100,8 @@ public class JdbcTemplateTests {
 		assertTrue("now it should have been set to case insensitive",
 				this.template.isResultsMapCaseInsensitive());
 
-		List<SqlParameter> params = new ArrayList<>();
-		params.add(new SqlOutParameter("a", 12));
-
-		Map<String, Object> out = this.template.call(conn -> conn.prepareCall("my query"), params);
+		Map<String, Object> out = this.template.call(
+				conn -> conn.prepareCall("my query"), Collections.singletonList(new SqlOutParameter("a", 12)));
 
 		assertThat(out, instanceOf(LinkedCaseInsensitiveMap.class));
 		assertNotNull("we should have gotten the result with upper case", out.get("A"));
@@ -1111,6 +1110,25 @@ public class JdbcTemplateTests {
 		verify(this.connection).close();
 	}
 
+	@Test  // SPR-16578
+	public void testEquallyNamedColumn() throws SQLException {
+		given(this.connection.createStatement()).willReturn(this.statement);
+
+		ResultSetMetaData metaData = mock(ResultSetMetaData.class);
+		given(metaData.getColumnCount()).willReturn(2);
+		given(metaData.getColumnLabel(1)).willReturn("x");
+		given(metaData.getColumnLabel(2)).willReturn("X");
+		given(this.resultSet.getMetaData()).willReturn(metaData);
+
+		given(this.resultSet.next()).willReturn(true, false);
+		given(this.resultSet.getObject(1)).willReturn("first value");
+		given(this.resultSet.getObject(2)).willReturn("second value");
+
+		Map<String, Object> map = this.template.queryForMap("my query");
+		assertEquals(1, map.size());
+		assertEquals("first value", map.get("x"));
+	}
+
 
 	private void mockDatabaseMetaData(boolean supportsBatchUpdates) throws SQLException {
 		DatabaseMetaData databaseMetaData = mock(DatabaseMetaData.class);