本文实例讲述了PHP实现的json类。分享给大家供大家参考。具体如下：

这里注意json_encode只有(PHP 5 >= 5.2.0, PECL json >= 1.2.0)才有

* @author  Matt Knapp <mdknapp[at]gmail[dot]com>
* @author  Brett Stimmerman <brettstimmerman[at]gmail[dot]com>
* @copyright 2005 Michal Migurski
* @version  CVS: $Id: JSON.php,v 1.31 2006/06/28 05:54:17 migurski Exp $
* @license  http://www.opensource.org/licenses/bsd-license.php
* @link  http://pear.php.net/pepr/pepr-proposal-show.php?id=198
*/
/**
* Marker constant for Services_JSON::decode(), used to flag stack state
*/
define('SERVICES_JSON_SLICE', 1);
/**
* Marker constant for Services_JSON::decode(), used to flag stack state
*/
define('SERVICES_JSON_IN_STR', 2);
/**
* Marker constant for Services_JSON::decode(), used to flag stack state
*/
define('SERVICES_JSON_IN_ARR', 3);
/**
* Marker constant for Services_JSON::decode(), used to flag stack state
*/
define('SERVICES_JSON_IN_OBJ', 4);
/**
* Marker constant for Services_JSON::decode(), used to flag stack state
*/
define('SERVICES_JSON_IN_CMT', 5);
/**
* Behavior switch for Services_JSON::decode()
*/
define('SERVICES_JSON_LOOSE_TYPE', 16);
/**
* Behavior switch for Services_JSON::decode()
*/
define('SERVICES_JSON_SUPPRESS_ERRORS', 32);
/**
* Converts to and from JSON format.
*
* Brief example of use:
*
* 
* // create a new instance of Services_JSON
* $json = new Services_JSON();
*
* // convert a complexe value to JSON notation, and send it to the browser
* $value = array('foo', 'bar', array(1, 2, 'baz'), array(3, array(4)));
* $output = $json->encode($value);
*
* print($output);
* // prints: ["foo","bar",[1,2,"baz"],[3,[4]]]
*
* // accept incoming POST data, assumed to be in JSON notation
* $input = file_get_contents('php://input', 1000000);
* $value = $json->decode($input);
*  */ class Services_JSON { /** * constructs a new JSON instance * * @param int $use object behavior flags; combine with boolean-OR * * possible values: * - SERVICES_JSON_LOOSE_TYPE: loose typing. * "{...}" syntax creates associative arrays * instead of objects in decode(). * - SERVICES_JSON_SUPPRESS_ERRORS: error suppression. * Values which can't be encoded (e.g. resources) * appear as NULL instead of throwing errors. * By default, a deeply-nested resource will * bubble up with an error, so all return values * from encode() should be checked with isError() */ function Services_JSON($use = 0) { $this->use = $use; } /** * convert a string from one UTF-16 char to one UTF-8 char * * Normally should be handled by mb_convert_encoding, but * provides a slower PHP-only method for installations * that lack the multibye string extension. * * @param string $utf16 UTF-16 character * @return string UTF-8 character * @access private */ function utf162utf8($utf16) { // oh please oh please oh please oh please oh please if(function_exists('mb_convert_encoding')) { return mb_convert_encoding($utf16, 'UTF-8', 'UTF-16'); } $bytes = (ord($utf16{0}) << 8) | ord($utf16{1}); switch(true) { case ((0x7F & $bytes) == $bytes): // this case should never be reached, because we are in ASCII range // see: http://www.cl.cam.ac.uk/~mgk25/unicode.html#utf-8 return chr(0x7F & $bytes); case (0x07FF & $bytes) == $bytes: // return a 2-byte UTF-8 character // see: http://www.cl.cam.ac.uk/~mgk25/unicode.html#utf-8 return chr(0xC0 | (($bytes >> 6) & 0x1F)) . chr(0x80 | ($bytes & 0x3F)); case (0xFFFF & $bytes) == $bytes: // return a 3-byte UTF-8 character // see: http://www.cl.cam.ac.uk/~mgk25/unicode.html#utf-8 return chr(0xE0 | (($bytes >> 12) & 0x0F)) . chr(0x80 | (($bytes >> 6) & 0x3F)) . chr(0x80 | ($bytes & 0x3F)); } // ignoring UTF-32 for now, sorry return ''; } /** * convert a string from one UTF-8 char to one UTF-16 char * * Normally should be handled by mb_convert_encoding, but * provides a slower PHP-only method for installations * that lack the multibye string extension. * * @param string $utf8 UTF-8 character * @return string UTF-16 character * @access private */ function utf82utf16($utf8) { // oh please oh please oh please oh please oh please if(function_exists('mb_convert_encoding')) { return mb_convert_encoding($utf8, 'UTF-16', 'UTF-8'); } switch(strlen($utf8)) { case 1: // this case should never be reached, because we are in ASCII range // see: http://www.cl.cam.ac.uk/~mgk25/unicode.html#utf-8 return $utf8; case 2: // return a UTF-16 character from a 2-byte UTF-8 char // see: http://www.cl.cam.ac.uk/~mgk25/unicode.html#utf-8 return chr(0x07 & (ord($utf8{0}) >> 2)) . chr((0xC0 & (ord($utf8{0}) << 6)) | (0x3F & ord($utf8{1}))); case 3: // return a UTF-16 character from a 3-byte UTF-8 char // see: http://www.cl.cam.ac.uk/~mgk25/unicode.html#utf-8 return chr((0xF0 & (ord($utf8{0}) << 4)) | (0x0F & (ord($utf8{1}) >> 2))) . chr((0xC0 & (ord($utf8{1}) << 6)) | (0x7F & ord($utf8{2}))); } // ignoring UTF-32 for now, sorry return ''; } /** * encodes an arbitrary variable into JSON format * * @param mixed $var any number, boolean, string, array, or object to be encoded. * see argument 1 to Services_JSON() above for array-parsing behavior. * if var is a strng, note that encode() always expects it * to be in ASCII or UTF-8 format! * * @return mixed JSON string representation of input var or an error if a problem occurs * @access public */ function encode($var) { switch (gettype($var)) { case 'boolean': return $var ? 'true' : 'false'; case 'NULL': return 'null'; case 'integer': return (int) $var; case 'double': case 'float': return (float) $var; case 'string': // STRINGS ARE EXPECTED TO BE IN ASCII OR UTF-8 FORMAT $ascii = ''; $strlen_var = strlen($var); /* * Iterate over every character in the string, * escaping with a slash or encoding to UTF-8 where necessary */ for ($c = 0; $c < $strlen_var; ++$c) { $ord_var_c = ord($var{$c}); switch (true) { case $ord_var_c == 0x08: $ascii .= 'b'; break; case $ord_var_c == 0x09: $ascii .= 't'; break; case $ord_var_c == 0x0A: $ascii .= 'n'; break; case $ord_var_c == 0x0C: $ascii .= 'f'; break; case $ord_var_c == 0x0D: $ascii .= 'r'; break; case $ord_var_c == 0x22: case $ord_var_c == 0x2F: case $ord_var_c == 0x5C: // double quote, slash, slosh $ascii .= '\'.$var{$c}; break; case (($ord_var_c >= 0x20) && ($ord_var_c <= 0x7F)): // characters U-00000000 - U-0000007F (same as ASCII) $ascii .= $var{$c}; break; case (($ord_var_c & 0xE0) == 0xC0): // characters U-00000080 - U-000007FF, mask 110XXXXX // see http://www.cl.cam.ac.uk/~mgk25/unicode.html#utf-8 $char = pack('C*', $ord_var_c, ord($var{$c + 1})); $c += 1; $utf16 = $this->utf82utf16($char); $ascii .= sprintf('u%04s', bin2hex($utf16)); break; case (($ord_var_c & 0xF0) == 0xE0): // characters U-00000800 - U-0000FFFF, mask 1110XXXX // see http://www.cl.cam.ac.uk/~mgk25/unicode.html#utf-8 $char = pack('C*', $ord_var_c, ord($var{$c + 1}), ord($var{$c + 2})); $c += 2; $utf16 = $this->utf82utf16($char); $ascii .= sprintf('u%04s', bin2hex($utf16)); break; case (($ord_var_c & 0xF8) == 0xF0): // characters U-00010000 - U-001FFFFF, mask 11110XXX // see http://www.cl.cam.ac.uk/~mgk25/unicode.html#utf-8 $char = pack('C*', $ord_var_c, ord($var{$c + 1}), ord($var{$c + 2}), ord($var{$c + 3})); $c += 3; $utf16 = $this->utf82utf16($char); $ascii .= sprintf('u%04s', bin2hex($utf16)); break; case (($ord_var_c & 0xFC) == 0xF8): // characters U-00200000 - U-03FFFFFF, mask 111110XX // see http://www.cl.cam.ac.uk/~mgk25/unicode.html#utf-8 $char = pack('C*', $ord_var_c, ord($var{$c + 1}), ord($var{$c + 2}), ord($var{$c + 3}), ord($var{$c + 4})); $c += 4; $utf16 = $this->utf82utf16($char); $ascii .= sprintf('u%04s', bin2hex($utf16)); break; case (($ord_var_c & 0xFE) == 0xFC): // characters U-04000000 - U-7FFFFFFF, mask 1111110X // see http://www.cl.cam.ac.uk/~mgk25/unicode.html#utf-8 $char = pack('C*', $ord_var_c, ord($var{$c + 1}), ord($var{$c + 2}), ord($var{$c + 3}), ord($var{$c + 4}), ord($var{$c + 5})); $c += 5; $utf16 = $this->utf82utf16($char); $ascii .= sprintf('u%04s', bin2hex($utf16)); break; } } return '"'.$ascii.'"'; case 'array': /* * As per JSON spec if any array key is not an integer * we must treat the the whole array as an object. We * also try to catch a sparsely populated associative * array with numeric keys here because some JS engines * will create an array with empty indexes up to * max_index which can cause memory issues and because * the keys, which may be relevant, will be remapped * otherwise. * * As per the ECMA and JSON specification an object may * have any string as a property. Unfortunately due to * a hole in the ECMA specification if the key is a * ECMA reserved word or starts with a digit the * parameter is only accessible using ECMAScript's * bracket notation. */ // treat as a JSON object if (is_array($var) && count($var) && (array_keys($var) !== range(0, sizeof($var) - 1))) { $properties = array_map(array($this, 'name_value'), array_keys($var), array_values($var)); foreach($properties as $property) { if(Services_JSON::isError($property)) { return $property; } } return '{' . join(',', $properties) . '}'; } // treat it like a regular array $elements = array_map(array($this, 'encode'), $var); foreach($elements as $element) { if(Services_JSON::isError($element)) { return $element; } } return '[' . join(',', $elements) . ']'; case 'object': $vars = get_object_vars($var); $properties = array_map(array($this, 'name_value'), array_keys($vars), array_values($vars)); foreach($properties as $property) { if(Services_JSON::isError($property)) { return $property; } } return '{' . join(',', $properties) . '}'; default: return ($this->use & SERVICES_JSON_SUPPRESS_ERRORS) ? 'null' : new Services_JSON_Error(gettype($var)." can not be encoded as JSON string"); } } /** * array-walking function for use in generating JSON-formatted name-value pairs * * @param string $name name of key to use * @param mixed $value reference to an array element to be encoded * * @return string JSON-formatted name-value pair, like '"name":value' * @access private */ function name_value($name, $value) { $encoded_value = $this->encode($value); if(Services_JSON::isError($encoded_value)) { return $encoded_value; } return $this->encode(strval($name)) . ':' . $encoded_value; } /** * reduce a string by removing leading and trailing comments and whitespace * * @param $str string string value to strip of comments and whitespace * * @return string string value stripped of comments and whitespace * @access private */ function reduce_string($str) { $str = preg_replace(array( // eliminate single line comments in '// ...' form '#^s*//(.+)$#m', // eliminate multi-line comments in '/* ... */' form, at start of string '#^s*/*(.+)*/#Us', // eliminate multi-line comments in '/* ... */' form, at end of string '#/*(.+)*/s*$#Us' ), '', $str); // eliminate extraneous space return trim($str); } /** * decodes a JSON string into appropriate variable * * @param string $str JSON-formatted string * * @return mixed number, boolean, string, array, or object * corresponding to given JSON input string. * See argument 1 to Services_JSON() above for object-output behavior. * Note that decode() always returns strings * in ASCII or UTF-8 format! * @access public */ function decode($str) { $str = $this->reduce_string($str); switch (strtolower($str)) { case 'true': return true; case 'false': return false; case 'null': return null; default: $m = array(); if (is_numeric($str)) { // Lookie-loo, it's a number // This would work on its own, but I'm trying to be // good about returning integers where appropriate: // return (float)$str; // Return float or int, as appropriate return ((float)$str == (integer)$str) ? (integer)$str : (float)$str; } elseif (preg_match('/^("|').*(1)$/s', $str, $m) && $m[1] == $m[2]) { // STRINGS RETURNED IN UTF-8 FORMAT $delim = substr($str, 0, 1); $chrs = substr($str, 1, -1); $utf8 = ''; $strlen_chrs = strlen($chrs); for ($c = 0; $c < $strlen_chrs; ++$c) { $substr_chrs_c_2 = substr($chrs, $c, 2); $ord_chrs_c = ord($chrs{$c}); switch (true) { case $substr_chrs_c_2 == 'b': $utf8 .= chr(0x08); ++$c; break; case $substr_chrs_c_2 == 't': $utf8 .= chr(0x09); ++$c; break; case $substr_chrs_c_2 == 'n': $utf8 .= chr(0x0A); ++$c; break; case $substr_chrs_c_2 == 'f': $utf8 .= chr(0x0C); ++$c; break; case $substr_chrs_c_2 == 'r': $utf8 .= chr(0x0D); ++$c; break; case $substr_chrs_c_2 == '\"': case $substr_chrs_c_2 == '\'': case $substr_chrs_c_2 == '\\': case $substr_chrs_c_2 == '\/': if (($delim == '"' && $substr_chrs_c_2 != '\'') || ($delim == "'" && $substr_chrs_c_2 != '\"')) { $utf8 .= $chrs{++$c}; } break; case preg_match('/\u[0-9A-F]{4}/i', substr($chrs, $c, 6)): // single, escaped unicode character $utf16 = chr(hexdec(substr($chrs, ($c + 2), 2))) . chr(hexdec(substr($chrs, ($c + 4), 2))); $utf8 .= $this->utf162utf8($utf16); $c += 5; break; case ($ord_chrs_c >= 0x20) && ($ord_chrs_c <= 0x7F): $utf8 .= $chrs{$c}; break; case ($ord_chrs_c & 0xE0) == 0xC0: // characters U-00000080 - U-000007FF, mask 110XXXXX //see http://www.cl.cam.ac.uk/~mgk25/unicode.html#utf-8 $utf8 .= substr($chrs, $c, 2); ++$c; break; case ($ord_chrs_c & 0xF0) == 0xE0: // characters U-00000800 - U-0000FFFF, mask 1110XXXX // see http://www.cl.cam.ac.uk/~mgk25/unicode.html#utf-8 $utf8 .= substr($chrs, $c, 3); $c += 2; break; case ($ord_chrs_c & 0xF8) == 0xF0: // characters U-00010000 - U-001FFFFF, mask 11110XXX // see http://www.cl.cam.ac.uk/~mgk25/unicode.html#utf-8 $utf8 .= substr($chrs, $c, 4); $c += 3; break; case ($ord_chrs_c & 0xFC) == 0xF8: // characters U-00200000 - U-03FFFFFF, mask 111110XX // see http://www.cl.cam.ac.uk/~mgk25/unicode.html#utf-8 $utf8 .= substr($chrs, $c, 5); $c += 4; break; case ($ord_chrs_c & 0xFE) == 0xFC: // characters U-04000000 - U-7FFFFFFF, mask 1111110X // see http://www.cl.cam.ac.uk/~mgk25/unicode.html#utf-8 $utf8 .= substr($chrs, $c, 6); $c += 5; break; } } return $utf8; } elseif (preg_match('/^[.*]$/s', $str) || preg_match('/^{.*}$/s', $str)) { // array, or object notation if ($str{0} == '[') { $stk = array(SERVICES_JSON_IN_ARR); $arr = array(); } else { if ($this->use & SERVICES_JSON_LOOSE_TYPE) { $stk = array(SERVICES_JSON_IN_OBJ); $obj = array(); } else { $stk = array(SERVICES_JSON_IN_OBJ); $obj = new stdClass(); } } array_push($stk, array('what' => SERVICES_JSON_SLICE, 'where' => 0, 'delim' => false)); $chrs = substr($str, 1, -1); $chrs = $this->reduce_string($chrs); if ($chrs == '') { if (reset($stk) == SERVICES_JSON_IN_ARR) { return $arr; } else { return $obj; } } //print("nparsing {$chrs}n"); $strlen_chrs = strlen($chrs); for ($c = 0; $c <= $strlen_chrs; ++$c) { $top = end($stk); $substr_chrs_c_2 = substr($chrs, $c, 2); if (($c == $strlen_chrs) || (($chrs{$c} == ',') && ($top['what'] == SERVICES_JSON_SLICE))) { // found a comma that is not inside a string, array, etc., // OR we've reached the end of the character list $slice = substr($chrs, $top['where'], ($c - $top['where'])); array_push($stk, array('what' => SERVICES_JSON_SLICE, 'where' => ($c + 1), 'delim' => false)); //print("Found split at {$c}: ".substr($chrs, $top['where'], (1 + $c - $top['where']))."n"); if (reset($stk) == SERVICES_JSON_IN_ARR) { // we are in an array, so just push an element onto the stack array_push($arr, $this->decode($slice)); } elseif (reset($stk) == SERVICES_JSON_IN_OBJ) { // we are in an object, so figure // out the property name and set an // element in an associative array, // for now $parts = array(); if (preg_match('/^s*(["'].*[^\]["'])s*:s*(S.*),?$/Uis', $slice, $parts)) { // "name":value pair $key = $this->decode($parts[1]); $val = $this->decode($parts[2]); if ($this->use & SERVICES_JSON_LOOSE_TYPE) { $obj[$key] = $val; } else { $obj->$key = $val; } } elseif (preg_match('/^s*(w+)s*:s*(S.*),?$/Uis', $slice, $parts)) { // name:value pair, where name is unquoted $key = $parts[1]; $val = $this->decode($parts[2]); if ($this->use & SERVICES_JSON_LOOSE_TYPE) { $obj[$key] = $val; } else { $obj->$key = $val; } } } } elseif ((($chrs{$c} == '"') || ($chrs{$c} == "'")) && ($top['what'] != SERVICES_JSON_IN_STR)) { // found a quote, and we are not inside a string array_push($stk, array('what' => SERVICES_JSON_IN_STR, 'where' => $c, 'delim' => $chrs{$c})); //print("Found start of string at {$c}n"); } elseif (($chrs{$c} == $top['delim']) && ($top['what'] == SERVICES_JSON_IN_STR) && ((strlen(substr($chrs, 0, $c)) - strlen(rtrim(substr($chrs, 0, $c), '\'))) % 2 != 1)) { // found a quote, we're in a string, and it's not escaped // we know that it's not escaped becase there is _not_ an // odd number of backslashes at the end of the string so far array_pop($stk); //print("Found end of string at {$c}: ".substr($chrs, $top['where'], (1 + 1 + $c - $top['where']))."n"); } elseif (($chrs{$c} == '[') && in_array($top['what'], array(SERVICES_JSON_SLICE, SERVICES_JSON_IN_ARR, SERVICES_JSON_IN_OBJ))) { // found a left-bracket, and we are in an array, object, or slice array_push($stk, array('what' => SERVICES_JSON_IN_ARR, 'where' => $c, 'delim' => false)); //print("Found start of array at {$c}n"); } elseif (($chrs{$c} == ']') && ($top['what'] == SERVICES_JSON_IN_ARR)) { // found a right-bracket, and we're in an array array_pop($stk); //print("Found end of array at {$c}: ".substr($chrs, $top['where'], (1 + $c - $top['where']))."n"); } elseif (($chrs{$c} == '{') && in_array($top['what'], array(SERVICES_JSON_SLICE, SERVICES_JSON_IN_ARR, SERVICES_JSON_IN_OBJ))) { // found a left-brace, and we are in an array, object, or slice array_push($stk, array('what' => SERVICES_JSON_IN_OBJ, 'where' => $c, 'delim' => false)); //print("Found start of object at {$c}n"); } elseif (($chrs{$c} == '}') && ($top['what'] == SERVICES_JSON_IN_OBJ)) { // found a right-brace, and we're in an object array_pop($stk); //print("Found end of object at {$c}: ".substr($chrs, $top['where'], (1 + $c - $top['where']))."n"); } elseif (($substr_chrs_c_2 == '/*') && in_array($top['what'], array(SERVICES_JSON_SLICE, SERVICES_JSON_IN_ARR, SERVICES_JSON_IN_OBJ))) { // found a comment start, and we are in an array, object, or slice array_push($stk, array('what' => SERVICES_JSON_IN_CMT, 'where' => $c, 'delim' => false)); $c++; //print("Found start of comment at {$c}n"); } elseif (($substr_chrs_c_2 == '*/') && ($top['what'] == SERVICES_JSON_IN_CMT)) { // found a comment end, and we're in one now array_pop($stk); $c++; for ($i = $top['where']; $i <= $c; ++$i) $chrs = substr_replace($chrs, ' ', $i, 1); //print("Found end of comment at {$c}: ".substr($chrs, $top['where'], (1 + $c - $top['where']))."n"); } } if (reset($stk) == SERVICES_JSON_IN_ARR) { return $arr; } elseif (reset($stk) == SERVICES_JSON_IN_OBJ) { return $obj; } } } } /** * @todo Ultimately, this should just call PEAR::isError() */ function isError($data, $code = null) { if (class_exists('pear')) { return PEAR::isError($data, $code); } elseif (is_object($data) && (get_class($data) == 'services_json_error' || is_subclass_of($data, 'services_json_error'))) { return true; } return false; } } if (class_exists('PEAR_Error')) { class Services_JSON_Error extends PEAR_Error { function Services_JSON_Error($message = 'unknown error', $code = null, $mode = null, $options = null, $userinfo = null) { parent::PEAR_Error($message, $code, $mode, $options, $userinfo); } } } else { /** * @todo Ultimately, this class shall be descended from PEAR_Error */ class Services_JSON_Error { function Services_JSON_Error($message = 'unknown error', $code = null, $mode = null, $options = null, $userinfo = null) { } } } ?>

希望本文所述对大家的php程序设计有所帮助。