UriComponentsBuilder - how to replace some of the queryParams and remove the unused?

Question

Hey i have this url that contains multiple query params - it is used for search. It's a hatehoas link

https://someurl/customers?customer-id={customer-id}&type={type}&something={something}

And i wish to replace only two of the the params

Map<String, String> params = new HashMap<>();
    params.put("customer-id", customerId);
    params.put("something", something)

    UriComponents customerUrl = UriComponentsBuilder
          .fromHttpUrl(specialURL)
          .buildAndExpand(params).encode();

But this throws.

java.lang.IllegalArgumentException: Map has no value for 'type'
    at org.springframework.web.util.UriComponents$MapTemplateVariables.getValue(UriComponents.java:346) ~[spring-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]

What is the best workaround here, let's say I have around 7 params, replacing them by an empty string or cutting string in half seems rather hacky.

Answer 1

UriComponents is always expect all the key data must be present in the map, below is the code which is used by UriComponents which throws the exception.

@Override
public Object getValue(String name) {
    if (!this.uriVariables.containsKey(name)) {
        throw new IllegalArgumentException("Map has no value for '" + name + "'");
    }
    return this.uriVariables.get(name);
}

Solution:

So to solve your problem you can try following code.

class Param extends HashMap<String, String>{


    @Override
    public String get(Object key) {
        if(!super.containsKey(key)){
            super.put(key.toString(), "");
        }
        return super.getOrDefault(key, "t");
    }

    @Override
    public boolean containsKey(Object arg0) {
        return true;
    }   
}

public class UriComponenet {

    public static void main(String[] args) {

        Param params = new Param();
        params.put("customer-id", "1");
        String specialURL="https://someurl/customers?customer-id={customer-id}&type={type}&something={something}";
        UriComponents customerUrl = UriComponentsBuilder
              .fromHttpUrl(specialURL)
              .buildAndExpand(params).encode();

        System.out.println(customerUrl);        
    }
}

I have extends the HashMap class to Param and then use that class as an input to buildAndExpand method.

I hope this will solve your problem.