json_last_error — Returns the last error occurred ## Return Values Returns an integer, the value can be one of the following constants: JSON error codes Constant Meaning Availability JSON_ERROR_NONE No error has occurred JSON_ERROR_DEPTH The maximum stack depth has been exceeded JSON_ERROR_STATE_MISMATCH Invalid or malformed JSON JSON_ERROR_CTRL_CHAR Control character error, possibly incorrectly encoded JSON_ERROR_SYNTAX Syntax error JSON_ERROR_UTF8 Malformed UTF-8 characters, possibly incorrectly encoded PHP 5.3.3 JSON_ERROR_RECURSION One or more recursive references in the value to be encoded PHP 5.5.0 JSON_ERROR_INF_OR_NAN One or more NAN or INF values in the value to be encoded PHP 5.5.0 JSON_ERROR_UNSUPPORTED_TYPE A value of a type that cannot be encoded was given PHP 5.5.0 JSON_ERROR_INVALID_PROPERTY_NAME A property name that cannot be encoded was given PHP 7.0.0 JSON_ERROR_UTF16 Malformed UTF-16 characters, possibly incorrectly encoded PHP 7.0.0 ## 例子 ~~~ <?php // A valid json string $json[] = '{"Organization": "PHP Documentation Team"}'; // An invalid json string which will cause an syntax // error, in this case we used ' instead of " for quotation $json[] = "{'Organization': 'PHP Documentation Team'}"; foreach ($json as $string) { echo 'Decoding: ' . $string; json_decode($string); switch (json_last_error()) { case JSON_ERROR_NONE: echo ' - No errors'; break; case JSON_ERROR_DEPTH: echo ' - Maximum stack depth exceeded'; break; case JSON_ERROR_STATE_MISMATCH: echo ' - Underflow or the modes mismatch'; break; case JSON_ERROR_CTRL_CHAR: echo ' - Unexpected control character found'; break; case JSON_ERROR_SYNTAX: echo ' - Syntax error, malformed JSON'; break; case JSON_ERROR_UTF8: echo ' - Malformed UTF-8 characters, possibly incorrectly encoded'; break; default: echo ' - Unknown error'; break; } echo PHP_EOL; } ?> ~~~