JSON Invalid UTF-8 middle byte

Question

This error happens when the (Jackson, this case) JSON engine tries to parse some JSON that is not encoded in UTF-8.

How to tell the engine that it should expect something different from UTF-8, such as UTF-16?

HttpHeaders requestHeaders = createSomeHeader(); RestTemplate restTemplate = new RestTemplate(); HttpEntity<?> requestEntity = new HttpEntity<Object>(requestHeaders); String url = "someurl" ResponseEntity<MyObject[]> arrayResponseEntity = restTemplate.exchange(url, HttpMethod.GET, requestEntity, MyObject[].class); 

error log:

Caused by: org.springframework.http.converter.HttpMessageNotReadableException: Could not read JSON: Invalid UTF-8 middle byte 0x20 at [Source: org.apache.http.conn.EofSensorInputStream@44d397b0; line: 92, column: 42]; nested exception is org.codehaus.jackson.JsonParseException: Invalid UTF-8 middle byte 0x20 at [Source: org.apache.http.conn.EofSensorInputStream@44d397b0; line: 92, column: 42] at org.springframework.http.converter.json.MappingJacksonHttpMessageConverter.readInternal(MappingJacksonHttpMessageConverter.java:138) at org.springframework.http.converter.AbstractHttpMessageConverter.read(AbstractHttpMessageConverter.java:154) at org.springframework.web.client.HttpMessageConverterExtractor.extractData(HttpMessageConverterExtractor.java:74) at org.springframework.web.client.RestTemplate$ResponseEntityResponseExtractor.extractData(RestTemplate.java:622) at org.springframework.web.client.RestTemplate$ResponseEntityResponseExtractor.extractData(RestTemplate.java:608) at org.springframework.web.client.RestTemplate.doExecute(RestTemplate.java:449) at org.springframework.web.client.RestTemplate.execute(RestTemplate.java:404) at org.springframework.web.client.RestTemplate.exchange(RestTemplate.java:380) ... 4 more Caused by: org.codehaus.jackson.JsonParseException: Invalid UTF-8 middle byte 0x20 at [Source: org.apache.http.conn.EofSensorInputStream@44d397b0; line: 92, column: 42] at org.codehaus.jackson.JsonParser._constructError(JsonParser.java:1213) at org.codehaus.jackson.impl.JsonParserMinimalBase._reportError(JsonParserMinimalBase.java:375) at org.codehaus.jackson.impl.Utf8StreamParser._reportInvalidOther(Utf8StreamParser.java:2132) at org.codehaus.jackson.impl.Utf8StreamParser._reportInvalidOther(Utf8StreamParser.java:2139) at org.codehaus.jackson.impl.Utf8StreamParser._decodeUtf8_3fast(Utf8StreamParser.java:1962) 

Answer 1

JSON data must be encoded as UTF-8, UTF-16 or UTF-32. The JSON decoder can determine the encoding by examining the first four octets of the byte stream:

       00 00 00 xx  UTF-32BE        00 xx 00 xx  UTF-16BE        xx 00 00 00  UTF-32LE        xx 00 xx 00  UTF-16LE        xx xx xx xx  UTF-8 

It sounds like the server is encoding data in some illegal encoding (ISO-8859-1, windows-1252, etc.)

Answer 2

I got this exception when in the Java Client Application I was serializing a JSON like this

String json = mapper.writeValueAsString(contentBean); 

and on the Server Side I was using Spring Boot as REST Endpoint. Exception was:

nested exception is com.fasterxml.jackson.databind.JsonMappingException: Invalid UTF-8 start byte 0xaa

My problem was, that I was not setting the correct encoding on the HTTP Client. This solved my problem:

updateRequest.setHeader("Content-Type", "application/json;charset=UTF-8"); StringEntity entity= new StringEntity(json, "UTF-8"); updateRequest.setEntity(entity); 

Android set content type HttpPost