What causes "data.export.json.error" in OtterMind/Chat2DB?

Inspect the wrapped JsonProcessingException for the offending type and convert that column to a String/plain value before batching.

OtterMind/Chat2DB · error · BusinessException

data.export.json.error

data.export.json.error

Error message

data.export.json.error

What it means

BusinessException 'data.export.json.error' from JsonDataExporter.writeBatch when ObjectMapper.writeValueAsString throws JsonProcessingException serializing a data batch to JSON during streaming export.

Source

Thrown at chat2db-community-server/chat2db-community-domain/chat2db-community-domain-core/src/main/java/ai/chat2db/community/domain/core/impl/task/export/json/JsonDataExporter.java:88

                        writer.println(",");
                    }
                    asyncContext.info(DateUtil.formatTime(new Date()) + ":" + String.format("Exported %d rows", n));
                    writeBatch(writer, objectMapper, dataBatch);
                    firstBatch = false;
                }
            }
            writer.println("]");
        }, asyncContext, asyncContext::checkCancelled);
    }

    private void writeBatch(PrintWriter writer, ObjectMapper objectMapper, List<Map<String, Object>> dataBatch) {
        try {
            String jsonBatch = objectMapper.writeValueAsString(dataBatch);
            writer.println(jsonBatch.substring(1, jsonBatch.length() - 1));
            writer.flush();
            dataBatch.clear();
        } catch (JsonProcessingException e) {
            throw new BusinessException("data.export.json.error", null, e);
        }
    }

}

View on GitHub (pinned to 5ee1e990e7)

Solutions

Inspect the wrapped JsonProcessingException for the offending type and convert that column to a String/plain value before batching.
Configure the ObjectMapper used by the exporter (register JavaTimeModule / SqlModule) to handle the JDBC types present.
Skip or stringify problematic columns in the export query/projection.

Defensive patterns

Strategy: try-catch

Validate before calling

// pre-configure the exporter ObjectMapper with JDBC/time modules
ObjectMapper om = new ObjectMapper();
om.registerModule(new com.fasterxml.jackson.datatype.jsr310.JavaTimeModule());
om.disable(com.fasterxml.jackson.databind.SerializationFeature.WRITE_DATES_AS_TIMESTAMPS);

Try / catch

try { String batch = objectMapper.writeValueAsString(dataBatch); }
catch (JsonProcessingException e) {
    throw new BusinessException("data.export.json.error", null, e);
}

Prevention

Register JavaTime/Sql modules on the export ObjectMapper.
Convert exotic JDBC types (BLOB/array) to String before batching.
Test export with the actual column types of high-variance tables.

When it happens

Trigger: A row map contains a value ObjectMapper cannot serialize (e.g. a non-JSON-serializable type, a self-referencing object, or a JDBC type without a serializer), or serialization hits a JDK type restriction.

Common situations: ResultSet column mapped to an exotic SQL/JDBC type (BLOB, array, custom); null-handling producing an unsupported Java type; mapper misconfiguration after an upgrade.

Related errors

AI-assisted analysis of OtterMind/Chat2DB@5ee1e990e7 (2026-08-14). Data as JSON: /api/errors/b705a3172711f9c4. Report an issue: GitHub.