如何在速度模板文件中访问地图

Question

when I passed a Map<String,String> in velocity template file, and when try to print the values of map it get sorted (on the basis of ASCII values).

I am doing as follows:

this is my velocity template file::

#set($tocList=${mapReference.mapValue})
#set($tocEntry="")

<div >
 #foreach($tocEntry in $tocList.keySet())
  <a href="#$tocEntry">$tocList.get($tocEntry)</a><br/>
 #end
</div>

My Java code is :

 Map<String, String> map=new HashMap<String, String>();
 Map<String,HashMap> m1=new HashMap<String, HashMap>();

   \\values that we want to print in template file

   map.put("sdfhfg", "Df lm"); 
   map.put("chdgfhd", "gBc Jk");
   map.put("dghjdhdf", "gI Ml");

   m1.put("mapValue", (HashMap) map);

  VelocityEngine velocityEngine = VelocityEngineFactory.getVelocityEngine();
  VelocityContext context = new VelocityContext();
  context.put("img",model);
  context.put("mapReference",m1);
  context.put("iterator", new IteratorTool());


  Template t = velocityEngine.getTemplate("tocTemplate.vm");
  StringWriter writer = new StringWriter();
    t.merge(context , writer);
    System.out.println(writer);

Output is:

 <div>
   <a href="#dghjdhdf">gI Ml</a><br/>
   <a href="#chdgfhd">gBc Jk</a><br/>
   <a href="#sdfhfg">Df lm</a><br/>
 </div>

Why these values get sorted? I want to print map as it is.

Answer 1

The order of the HasMap will not remain constant over time, from Javadoc :

This class makes no guarantees as to the order of the map; in particular, it does not guarantee that the order will remain constant over time.

To remain the order, you can consider use LinkedHashMap as following suggested:

This linked list defines the iteration ordering, which is normally the order in which keys were inserted into the map