Spring default characterEncoding

[vojkny]

Since Spring 5.2 MediaType.APPLICATION_JSON_UTF8 is @deprecated as described within MediaType class:

/**
 * A String equivalent of \{@link MediaType#APPLICATION_JSON_UTF8}.
 * @deprecated as of 5.2 in favor of \{@link #APPLICATION_JSON_VALUE}
 * since major browsers like Chrome
 * <a href="https://bugs.chromium.org/p/chromium/issues/detail?id=438464">
 * now comply with the specification</a> and interpret correctly UTF-8 special
 * characters without requiring a \{@code charset=UTF-8} parameter.
 */
@Deprecated
public static final String APPLICATION_JSON_UTF8_VALUE = "application/json;charset=UTF-8";

So basically everyone should be using MediaType.APPLICATION_JSON_VALUE without (UTF8 information) instead. This is unfortunately in conflict with MockHttpServletResponse:

private String characterEncoding = "ISO-8859-1";

So even thought UTF8 is expected by default, the testing environment is in violation with aboves:

now comply with the specification</a> and interpret correctly UTF-8 special

The tests which explicitly don't override this encoding will fail.

[rstoyanchev]

The characterEncoding in MockHttpServletResponse simply reflects the Serlvet spec default. It shouldn't interfere with MappingJackson2HttpMessageConverter which writes UTF-8 directly to the OutputStream. Can you clarify how tests fail?

[vojkny]

The characterEncoding in MockHttpServletResponse simply reflects the Serlvet spec default. It shouldn't interfere with MappingJackson2HttpMessageConverter which writes UTF-8 directly to the OutputStream. Can you clarify how tests fail?

When the response from a JSON endpoint contains UTF-8 characters (ěščřžýá), then the MockHttpServletResponse will consider them as ISO-8859-1 and the these characters will be received broken. If the tests perform assertEquals on such strings, they will fail.

[rstoyanchev]

So you're probably doing this?

assertEquals("...", response.getContentAsString());

but should be:

assertEquals("...", response.getContentAsString(StandardCharsets.UTF_8));

[vojkny]

The problem is that until having original aplication/json; charset=UTF-8 this worked correctly.

again:

now comply with the specification</a> and interpret correctly UTF-8 special

it is just strange to migrate to version without charset=UTF-8 when all tests are now broken.

[rstoyanchev]

Right but the change reflects the fact that it is now up to clients to be compliant and interpret this correctly. In MockMvc we automatically interpret JSON as UTF-8 but in this case you're reading directly from the response and it is up to your tests to do that. It is too low level a place for us to start adding functionality like that.

[vojkny]

Ok, thanks.