Mybatis-3: Remove blank lines in SQL

[zhaoxi1988]

Question:
MyBatis build SQL include many blank lines from XML.
The blank lines is unnecessary.

https://issues.apache.org/jira/browse/IBATIS-143

class XMLScriptBuilder
Let XNode replace '\n' or "\r\n" to ' ' .
I want the feature can be configurable.

[kazuki43zoo]

Hi @zhaoxi1988 , contributing welcome!! :D

[zhaoxi1988]

Oh. I accept it.

By the way.
Why do not mybatis's package name 'org.apache.mybatis' ?

[George5814]

@zhaoxi1988 Is the problem solved?

[zhaoxi1988]

@George5814 Still not solved...I busy on mybatis UnitTest...

[zhaoxi1988]

@George5814
My idea:
1.add in org.apache.ibatis.session.Configuration
2.push configuration down , let SqlSourceBuilder trim '\r|\n' or replace('\r|\n', ' ')

单元测试在IntelliJ上, 只安装JDK8有点尴尬...

[harawata]

I'm wondering why this feature request gets many votes.
Is there any actual harm caused by the extra blank lines?

[George5814]

This is to delete the extra whitespace produced by the dynamic tags, not to beautify the SQL.
Improve readability.

[harawata]

@George5814
Recent versions of MyBatis remove blank lines when printing the log, so where do you see the SQLs with blank lines?

[zhaoxi1988]

@harawata I was an DBA. I see the problem like MySQL truncate the SQL because of the many blank lines.

[harawata]

@zhaoxi1988 ,
Do you mean that the length of a generated SQL exceeds max_allowed_packet ?

[zhaoxi1988]

@harawata

Do you mean that the length of a generated SQL exceeds max_allowed_packet

It is not.
It is MySQL's query-log or InnoDB log when had a dead lock.

[harawata]

@zhaoxi1988 ,

Thank you for the comment!

It is MySQL's query-log or InnoDB log when had a dead lock.

Okay. As I commented on the PR, the best we can do is to reduce the number of line breaks, probably.

[zhboseu]

Question:
MyBatis build SQL include many blank lines from XML.
The blank lines is unnecessary.

https://issues.apache.org/jira/browse/IBATIS-143

class XMLScriptBuilder
Let XNode replace '\n' or "\r\n" to ' ' .
I want the feature can be configurable.

Hi, is this problem solved?

[harawata]

Nope.
If it's very important, writing a custom language driver and script builder should work.

The language driver can be pretty simple.

public class CustomXmlLanguageDriver extends XMLLanguageDriver {
  @Override
  public SqlSource createSqlSource(Configuration configuration, XNode script, Class<?> parameterType) {
    CustomXmlScriptBuilder builder = new CustomXmlScriptBuilder(configuration, script, parameterType);
    return builder.parseScriptNode();
  }
}

CustomXmlScriptBuilder is almost identical to org.apache.ibatis.scripting.xmltags.XMLScriptBuilder.
Just remove whitespaces in parseDynamicTags() method as @zhaoxi1988 did in #1153 .

And set defaultScriptLanguage in the config.

<settings>
  <setting name="defaultScriptingLanguage"
    value="xxx.yyy.CustomXmlLanguageDriver" />
</settings>

[harawata]

It might be cleaner to do the substitution in the language driver.

import java.util.regex.Pattern;

import org.apache.ibatis.builder.xml.XMLMapperEntityResolver;
import org.apache.ibatis.mapping.SqlSource;
import org.apache.ibatis.parsing.PropertyParser;
import org.apache.ibatis.parsing.XNode;
import org.apache.ibatis.parsing.XPathParser;
import org.apache.ibatis.scripting.defaults.RawSqlSource;
import org.apache.ibatis.scripting.xmltags.DynamicSqlSource;
import org.apache.ibatis.scripting.xmltags.TextSqlNode;
import org.apache.ibatis.scripting.xmltags.XMLLanguageDriver;
import org.apache.ibatis.session.Configuration;

public class CompactXMLLanguageDriver extends XMLLanguageDriver {
  private static final Pattern pattern = Pattern.compile("[\\s]+");

  @Override
  public SqlSource createSqlSource(Configuration configuration, XNode script, Class<?> parameterType) {
    script.getNode().setTextContent(pattern.matcher(script.getNode().getTextContent()).replaceAll(" "));
    return super.createSqlSource(configuration, script, parameterType);
  }

  @Override
  public SqlSource createSqlSource(Configuration configuration, String script, Class<?> parameterType) {
    if (script.startsWith("<script>")) {
      XPathParser parser = new XPathParser(script, false, configuration.getVariables(), new XMLMapperEntityResolver());
      return createSqlSource(configuration, parser.evalNode("/script"), parameterType);
    } else {
      script = PropertyParser.parse(pattern.matcher(script).replaceAll(" "), configuration.getVariables());
      TextSqlNode textSqlNode = new TextSqlNode(script);
      if (textSqlNode.isDynamic()) {
        return new DynamicSqlSource(configuration, textSqlNode);
      } else {
        return new RawSqlSource(configuration, script, parameterType);
      }
    }
  }
}

You don't have to modify XMLScriptBuilder anymore.

[harawata]

Fixed via #1901
We added a new option shrinkWhitespacesInSql
Please test 3.5.5.-SNAPSHOT.