What are the second parameters for `json_encode`?

json_encode The second function parameter is optional and is used to specify encoding options. Here are some commonly used encoding options:

1. JSON_HEX_QUOTEscape double quotation marks to \u0022。
2. JSON_HEX_TAG: In HTML tags < 和 > Escape sequence:\u003C 和 \u003E。
3. JSON_HEX_AMPCharacter: & Escape sequence: \u0026。
4. JSON_HEX_APOSEscape a single quotation mark to \u0027。
5. JSON_NUMERIC_CHECKForces a string-valued number to be converted to a numeric type.
6. JSON_PRETTY_PRINTFormat JSON data for easy readability.
7. JSON_UNESCAPED_UNICODE: Does not encode Unicode characters.
8. JSON_UNESCAPED_SLASHESDo not encode斜杠 characters.
9. JSON_FORCE_OBJECTCast a non-associative array into an associative array.

These options can be used individually or in combination using the bitwise OR operator. | Combined operator usage, e.g.:

$options = JSON_PRETTY_PRINT | JSON_UNESCAPED_UNICODE;
$jsonString = json_encode($data, $options);