FeignException ByteBuffer to String - Java

Introduction

In some cases, when using the Feign HTTP client in Java, you may encounter a FeignException that contains a body as a ByteBuffer. This can be challenging to work with, as the ByteBuffer needs to be converted to a String before it can be processed. In this tutorial, we will explore how to do this conversion in Java.

Converting ByteBuffer to String

To convert a ByteBuffer to a String in Java, we can use the Charset class to decode the ByteBuffer into a string. Here's an example of how to do this in Feign:

public String getResponseBody(FeignException e) {
    if (e.responseBody().isPresent()) {
        ByteBuffer buffer = e.responseBody().get().asByteBuffer();
        Charset charset = Charset.forName("UTF-8");
        return charset.decode(buffer).toString();
    }
    return null;
}

In this example, we first check if the responseBody is present in the FeignException. If it is, we get the body as a ByteBuffer and use the Charset.decode() method to convert it to a String.

Conclusion

Converting a ByteBuffer to a String can be a bit tricky, especially when working with FeignExceptions. However, by using the Charset class in Java, we can easily decode the ByteBuffer and obtain a String that can be processed as needed.