A new option (shrinkWhitespacesInSql) to remove extra whitespaces from SQL

src/main/java/org/apache/ibatis/builder/SqlSourceBuilder.java

@@ -22,6 +22,7 @@
 import org.apache.ibatis.mapping.ParameterMapping;
 import org.apache.ibatis.mapping.SqlSource;
 import org.apache.ibatis.parsing.GenericTokenParser;
+import org.apache.ibatis.parsing.StringParser;
 import org.apache.ibatis.parsing.TokenHandler;
 import org.apache.ibatis.reflection.MetaClass;
 import org.apache.ibatis.reflection.MetaObject;
@@ -42,7 +43,12 @@ public SqlSourceBuilder(Configuration configuration) {
   public SqlSource parse(String originalSql, Class<?> parameterType, Map<String, Object> additionalParameters) {
     ParameterMappingTokenHandler handler = new ParameterMappingTokenHandler(configuration, parameterType, additionalParameters);
     GenericTokenParser parser = new GenericTokenParser("#{", "}", handler);
-    String sql = parser.parse(originalSql);
+    String sql;
+    if (configuration.isMinifySqlEnabled()) {
+      sql = parser.parse(StringParser.removeBreakingWhitespace(originalSql));
+    } else {
+      sql = parser.parse(originalSql);
+    }
     return new StaticSqlSource(configuration, sql, handler.getParameterMappings());
   }
 

src/main/java/org/apache/ibatis/logging/jdbc/BaseJdbcLogger.java

@@ -26,10 +26,10 @@
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
-import java.util.StringTokenizer;
 import java.util.stream.Collectors;
 
 import org.apache.ibatis.logging.Log;
+import org.apache.ibatis.parsing.StringParser;
 import org.apache.ibatis.reflection.ArrayUtil;
 
 /**
@@ -121,13 +121,7 @@ protected void clearColumnInfo() {
   }
 
   protected String removeBreakingWhitespace(String original) {
-    StringTokenizer whitespaceStripper = new StringTokenizer(original);
-    StringBuilder builder = new StringBuilder();
-    while (whitespaceStripper.hasMoreTokens()) {
-      builder.append(whitespaceStripper.nextToken());
-      builder.append(" ");
-    }
-    return builder.toString();
+    return StringParser.removeBreakingWhitespace(original);
   }
 
   protected boolean isDebugEnabled() {

src/main/java/org/apache/ibatis/parsing/StringParser.java

@@ -0,0 +1,31 @@
+/*
+ *    Copyright 2009-2020 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.
+ *    You may obtain a copy of the License at
+ *
+ *       http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *    Unless required by applicable law or agreed to in writing, software
+ *    distributed under the License is distributed on an "AS IS" BASIS,
+ *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *    See the License for the specific language governing permissions and
+ *    limitations under the License.
+ */
+package org.apache.ibatis.parsing;
+
+import java.util.StringTokenizer;
+
+public class StringParser {
+
+  public static String removeBreakingWhitespace(String original) {
+    StringTokenizer whitespaceStripper = new StringTokenizer(original);
+    StringBuilder builder = new StringBuilder();
+    while (whitespaceStripper.hasMoreTokens()) {
+      builder.append(whitespaceStripper.nextToken());
+      builder.append(" ");
+    }
+    return builder.toString().trim();
+  }
+}

src/main/java/org/apache/ibatis/session/Configuration.java

@@ -113,6 +113,7 @@ public class Configuration {
   protected boolean callSettersOnNulls;
   protected boolean useActualParamName = true;
   protected boolean returnInstanceForEmptyRow;
+  protected boolean minifySqlEnabled;
 
   protected String logPrefix;
   protected Class<? extends Log> logImpl;
@@ -266,6 +267,14 @@ public void setReturnInstanceForEmptyRow(boolean returnEmptyInstance) {
     this.returnInstanceForEmptyRow = returnEmptyInstance;
   }
 
+  public boolean isMinifySqlEnabled() {
+    return minifySqlEnabled;
+  }
+
+  public void setMinifySqlEnabled(boolean minifySqlEnabled) {
+    this.minifySqlEnabled = minifySqlEnabled;
+  }
+
   public String getDatabaseId() {
     return databaseId;
   }

src/test/java/org/apache/ibatis/builder/SqlSourceBuilderTest.java

@@ -0,0 +1,62 @@
+/*
+ *    Copyright 2009-2020 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.
+ *    You may obtain a copy of the License at
+ *
+ *       http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *    Unless required by applicable law or agreed to in writing, software
+ *    distributed under the License is distributed on an "AS IS" BASIS,
+ *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *    See the License for the specific language governing permissions and
+ *    limitations under the License.
+ */
+package org.apache.ibatis.builder;
+
+import java.io.Reader;
+import org.apache.ibatis.builder.xml.XMLConfigBuilder;
+import org.apache.ibatis.io.Resources;
+import org.apache.ibatis.mapping.BoundSql;
+import org.apache.ibatis.mapping.SqlSource;
+import org.apache.ibatis.session.Configuration;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.Test;
+
+public class SqlSourceBuilderTest {
+
+  private static Configuration configuration;
+  private static SqlSourceBuilder sqlSourceBuilder;
+  String sqlFromXml = "SELECT * \n        FROM user\n        WHERE user_id = 1";
+
+  @BeforeAll
+  static void setUp() throws Exception {
+    // create an SqlSessionFactory
+    try (Reader reader = Resources
+      .getResourceAsReader("org/apache/ibatis/submitted/empty_row/mybatis-config.xml")) {
+      XMLConfigBuilder parser = new XMLConfigBuilder(reader, null, null);
+      configuration = parser.parse();
+    }
+
+    sqlSourceBuilder = new SqlSourceBuilder(configuration);
+  }
+
+  @Test
+  void testMinifySqlEnabledIsFalse() {
+    SqlSource sqlSource = sqlSourceBuilder.parse(sqlFromXml, null, null);
+    BoundSql boundSql = sqlSource.getBoundSql(null);
+    String actual = boundSql.getSql();
+    Assertions.assertEquals(sqlFromXml, actual);
+  }
+
+  @Test
+  void testMinifySqlEnabledIsTrue() {
+    configuration.setMinifySqlEnabled(true);
+    SqlSource sqlSource = sqlSourceBuilder.parse(sqlFromXml, null, null);
+    BoundSql boundSql = sqlSource.getBoundSql(null);
+    String actual = boundSql.getSql();
+    Assertions.assertNotEquals(sqlFromXml, actual);
+  }
+}