How to access values from list of maps in Apache camel message body - arraylist

Question

Perhaps this is easy, but I am somehow not able to crack it yet. Message body for an exchange is basically a list of maps with both key & value being string. As example,
[{'key'='val1'}, {'key'='val2'},...]
I am using simple expression to set this as a property which I would be using in subsequent routes. This is how I am setting it:
.setProperty("myProperty", simple("${body}"))
But this sets the complete body. I just want to (somehow) set only the values part to avoid setting the entire list of maps. What I have tried and not working so far:
.setProperty("myProperty", simple("${body}['key']"))
.setProperty("myProperty", simple("${body}[*]['key']"))
.setProperty("myProperty", simple("${body}[0]['key']")) // this returns only the first value, I want all
Any idea/suggestion how can I achieve this ?

Answer 1

You can access every level of your body with Simple expressions:
${body} // get whole list of maps
${body[0]} // get first map in the list (index 0)
${body[0][key]} // get value of key "key" from the first map in the list
What you cannot do in a Simple expression is a conversion of your data structure in another one.
However, you can simply plug a Java bean into your route
from("direct:start")
...
.bean(MyConversionBean.class)
...;
And do the conversion with Java
public class MyConversionBean {
public List<String> convertBody() {
// extract all values (or whatever) with Java;
return listOfValues;
}
}