apache camel: replace function - replace

Question

I want to use replace function in apache camel but have trouble with this. here is my code:
"firstName" : "aaa",
"lastName" : []
and my desire output is like this:
"firstName" : "aaa",
"lastName" : ""
I use this code for transform:
<transform>
<simple>${body.replace("[]","")}</simple>
</transform>
but the problem is not showing double quotation, actually I get this:
"firstName" : "aaa",
"lastName" :
I used &quot also, but do not work. Thanks in advance

Answer 1

I guess the correct replace call would contain escaped double quotes (I use Java DSL)
.transform(simple("${body.replace('[]', '\"\"')}"))
But that does not work, the empty double quotes do not show up in the result. Perhaps they are "evaluated to empty".
Original body: "firstName" : "aaa" "lastName" : []
Transformed body: "firstName" : "aaa" "lastName" :
However, you can do a workaround by replacing empty brackets in a first step to empty double quotes with a "special helper character" just to make sure the replace string cannot be interpreted as empty. I used the plus sign (+) in my example below.
In a second step you can replace the helper character with nothing and so the empty double quotes stay in the result.
.transform(simple("${body.replace('[]', '+\"\"')}"))
.transform(simple("${body.replace('+', '')}"))
This works for me.
Original body: "firstName" : "aaa" "lastName" : []
Transformed body: "firstName" : "aaa" "lastName" : ""
You would need to use a helper character that is not contained in your body. Otherwise the second step would perhaps remove something you do not want to.