Custom encoders and decoders

The Feign Builder API allows us to create custom encoders for a request, and decoders for a response, to the Feign client.

Custom encoder

Let's create a custom encoder for a request body.

The request body data has been sent to the server by a POST method using either the String or byte[] parameter. You can add a Content-Type header:

interface AccountService { 
   @PostMapping("/account/") 
   @Headers("Content-Type: application/json") 
   Account create(@RequestBody Account account); 
} 

Let's configure your own custom encoder; now it will be the type-safe request body. Let's see the following example using the feign-gson extension:

class Account { 
    Integer accountId; 
   Double balance; 
   Integer customerId; 
   String accountType; 
   String branchCode; 
   String bank; 
 
public Account(Integer accountId, Double balance, Integer customerId, String accountType, String branchCode, 
               String bank) { 
         super(); 
         this.accountId = accountId...