The Mathod of nodeHandlers need to be enhanced

[zhangweidavid]

https://github.com/mybatis/mybatis-3/blob/master/src/main/java/org/apache/ibatis/scripting/xmltags/XMLScriptBuilder.java

 NodeHandler nodeHandlers(String nodeName) {
    Map<String, NodeHandler> map = new HashMap<String, NodeHandler>();
    map.put("trim", new TrimHandler());
    map.put("where", new WhereHandler());
    map.put("set", new SetHandler());
    map.put("foreach", new ForEachHandler());
    map.put("if", new IfHandler());
    map.put("choose", new ChooseHandler());
    map.put("when", new IfHandler());
    map.put("otherwise", new OtherwiseHandler());
    map.put("bind", new BindHandler());
    return map.get(nodeName);
  }

These handlers are thread-safe, so they do not need to be created every time。
Using a global Map instead of local variables might be better?

MyBatis version

3.3.1

Database vendor and version

Test case or example project

Steps to reproduce

Expected result

Actual result