使用javax.json从列表创建json

Question

I have a List with 3000 items and I have to create a json from it and send it to my client side code which is Extjs. As JsonArrayBuilder does not accept list, I'm iterating through the list and add create each json object and finally send it to the client side. The problem is that this process takes 13 seconds which is really high.

Here is the way I make this json array.

 JsonObjectBuilder builder = Json.createObjectBuilder();
 JsonArrayBuilder childrenArrayBuilder = Json.createArrayBuilder();
        builder.add("success", true);
        builder.add("children, childrenArrayBuilder);

here is how I iterate through the list

           for (TagDefinitionProject tt : myList) {

            childrenArrayBuilder.add(
                    Json.createObjectBuilder()
                    .add("id", getTreeNodeId(tt.getTag()) + "-" + (idSplit[1]))
                    .add("nodeStatus", tt.getStatus())
                    .add("text", tt.getNJTagName())
                    .add("tagNJName", tt.getTag().getName())
                    .add("baseType", tt.getTag().getBaseType().getName())
                    .add("definitionType", def)
                    .add("leaf", (tt.getTag().getChildren().size() == 1 || tt.getTag().getChildren().get(1).getChild().equals(tt.getTag()))));
            }

How can improve the performance here?

Answer 1

The preferred method of creating multiple builders with the javax Json library is by using JsonBuilderFactory. I've modified your code below.

     // Create a new factory. The argument, config, can be null or
     // contain a Map with configuration values for the created builders.
     JsonBuilderFactory factory = Json.createBuilderFactory(config);
     JsonObjectBuilder builder = factory.createObjectBuilder();
     JsonArrayBuilder childrenArrayBuilder = factory.createArrayBuilder();
            builder.add("success", true);
            builder.add("children", childrenArrayBuilder);


               for (TagDefinitionProject tt : myList) {

                childrenArrayBuilder.add(
                        factory.createObjectBuilder()
                        .add("id", getTreeNodeId(tt.getTag()) + "-" + (idSplit[1]))
                        .add("nodeStatus", tt.getStatus())
                        .add("text", tt.getNJTagName())
                        .add("tagNJName", tt.getTag().getName())
                        .add("baseType", tt.getTag().getBaseType().getName())
                        .add("definitionType", def)
                        .add("leaf", (tt.getTag().getChildren().size() == 1 || tt.getTag().getChildren().get(1).getChild().equals(tt.getTag()))));
                }