How to get an object from a list of object in Freemarker

Question

I am trying to get one object returned from a list of objects;

list = [{"name":"Joe","id":1},{"name":"Fred","id":2}]

I want to output the object exactly like the format below;

{"name":"Joe","id":1}

It throws errors when I want to access the object in its entirety;

${list?first} -> Error: Expected a string or something automatically...

Testing this on https://try.freemarker.apache.org/ but I can't seem to be able to extract the full first object, whilst accessing a property from that object works fine..?

I understand that this is somewhat of an odd use case to display the object like that. I need it for a business program that uses freemarker and I want to assign the object back into a variable, which accepts this format.

Ori Marko · Accepted Answer · 2019-04-04 05:31:18Z

2

You can show values that can be converted to String as error (below) suggest

<#assign item = list[0]>
${item.name} ${item.id}

For "${...}" content: Expected a string or something automatically convertible to 
string (number, date or boolean), or "template output" , but this has evaluated to a 
sequence (ArrayList wrapped into f.t.DefaultListAdapter):
==> list  [in nameless template at line 1, column 3]

You can check freemarker parse a JSON answers, for executing similar as:

<#assign array = '[{"name":"Joe","id":1},{"name":"Fred","id":2}]'> 
<#assign object = array?eval[0]> 
<#list object?keys as key>"${key}":"${object[key]}"
</#list>

edited Apr 4, 2019 at 5:31

answered Apr 3, 2019 at 11:52

Ori Marko

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5 Comments

Bastiaan Over a year ago

I can do the same with ${list?first.name}, but how to retrieve the full object like {"name":"Joe","id":1} ? The object properties are not always the same, so I just want to have the full object.

Ori Marko Over a year ago

@Bastiaan you get it in first line <#assign item = list[0]>

Bastiaan Over a year ago

I understand that items contains the first object. However I still cannot output exactly {"name":"Joe","id":1} in any way? When I do the assign and then after that ${item} I get the exact same error. Have elaborated a bit more in the question to explain the use case

Ori Marko Over a year ago

@Bastiaan stackoverflow.com/questions/13087436/…

Bastiaan Over a year ago

Thanks! I have it working, do you want to update your answer with this, so I can accept it as the answer? <#assign array = '[{"name":"Joe","id":1},{"name":"Fred","id":2}]'> <#assign object = array?eval[0]> <#list object?keys as key>"${key}":"${object[key]}"</#list>

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