PHP实现的同步推荐操作API接口案例分析
385
2024-01-10
(PHP 5 >= 5.2.0, PECL json >= 1.2.0)
json_encode — 对变量进行 JSON 编码
说明
string json_encode ( mixed$value
[, int $options = 0
] )
返回 value 值的 JSON 形式
参数
value
待编码的 value ，除了resource
类型之外，可以为任何数据类型
该函数只能接受 UTF-8 编码的数据
options
由以下常量组成的二进制掩码： JSON_HEX_QUOT,
JSON_HEX_TAG,
JSON_HEX_AMP,
JSON_HEX_APOS,
JSON_NUMERIC_CHECK,
JSON_PRETTY_PRINT,
JSON_UNESCAPED_SLASHES,
JSON_FORCE_OBJECT,
JSON_UNESCAPED_UNICODE.
返回值
编码成功则返回一个以 JSON 形式表示的 string 或者在失败时返回 FALSE 。
更新日志
版本
说明
5.4.0
options 参数增加常量：
JSON_PRETTY_PRINT, JSON_UNESCAPED_SLASHES, 和 JSON_UNESCAPED_UNICODE。
5.3.3
options 参数增加常量：JSON_NUMERIC_CHECK。
5.3.0
增加 options 参数.
范例
Example #1 A json_encode() 的例子
<?php
$arr = array ('a'=>1,'b'=>2,'c'=>3,'d'=>4,'e'=>5);
echo json_encode($arr);
?>
以上例程会输出：
{"a":1,"b":2,"c":3,"d":4,"e":5}
Example #2 json_encode() 函数中 options 参数的用法
<?php
$a = array('<foo>',"'bar'",'"baz"','&blong&', "xc3xa9");
echo "Normal: ", json_encode($a), "n";
echo "Tags: ", json_encode($a, JSON_HEX_TAG), "n";
echo "Apos: ", json_encode($a, JSON_HEX_APOS), "n";
echo "Quot: ", json_encode($a, JSON_HEX_QUOT), "n";
echo "Amp: ", json_encode($a, JSON_HEX_AMP), "n";
echo "Unicode: ", json_encode($a, JSON_UNESCAPED_UNICODE), "n";
echo "All: ", json_encode($a, JSON_HEX_TAG | JSON_HEX_APOS | JSON_HEX_QUOT | JSON_HEX_AMP | JSON_UNESCAPED_UNICODE), "nn";
$b = array();
echo "Empty array output as array: ", json_encode($b), "n";
echo "Empty array output as object: ", json_encode($b, JSON_FORCE_OBJECT), "nn";
$c = array(array(1,2,3));
echo "Non-associative array output as array: ", json_encode($c), "n";
echo "Non-associative array output as object: ", json_encode($c, JSON_FORCE_OBJECT), "nn";
$d = array('foo' => 'bar', 'baz' => 'long');
echo "Associative array always output as object: ", json_encode($d), "n";
echo "Associative array always output as object: ", json_encode($d, JSON_FORCE_OBJECT), "nn";
?>
以上例程会输出：
Normal: ["<foo>","'bar'",""baz"","&blong&","u00e9"]
Tags: ["u003Cfoou003E","'bar'",""baz"","&blong&","u00e9"]
Apos: ["<foo>","u0027baru0027",""baz"","&blong&","u00e9"]
Quot: ["<foo>","'bar'","u0022bazu0022","&blong&","u00e9"]
Amp: ["<foo>","'bar'",""baz"","u0026blongu0026","u00e9"]
Unicode: ["<foo>","'bar'",""baz"","&blong&","é"]
All: ["u003Cfoou003E","u0027baru0027","u0022bazu0022","u0026blongu0026","é"]
Empty array output as array: []
Empty array output as object: {}
Non-associative array output as array: [[1,2,3]]
Non-associative array output as object: {"0":{"0":1,"1":2,"2":3}}
Associative array always output as object: {"foo":"bar","baz":"long"}
Associative array always output as object: {"foo":"bar","baz":"long"}
Example #3 连续与非连续数组示例
<?php
echo "连续数组".PHP_EOL;
$sequential = array("foo", "bar", "baz", "blong");
var_dump(
$sequential,
json_encode($sequential)
);
echo PHP_EOL."非连续数组".PHP_EOL;
$nonsequential = array(1=>"foo", 2=>"bar", 3=>"baz", 4=>"blong");
var_dump(
$nonsequential,
json_encode($nonsequential)
);
echo PHP_EOL."删除一个连续数组值的方式产生的非连续数组".PHP_EOL;
unset($sequential[1]);
var_dump(
$sequential,
json_encode($sequential)
);
?>
以上例程会输出：
连续数组
array(4) {
[0]=>
string(3) "foo"
[1]=>
string(3) "bar"
[2]=>
string(3) "baz"
[3]=>
string(5) "blong"
}
string(27) "["foo","bar","baz","blong"]"
非连续数组
array(4) {
[1]=>
string(3) "foo"
[2]=>
string(3) "bar"
[3]=>
string(3) "baz"
[4]=>
string(5) "blong"
}
string(43) "{"1":"foo","2":"bar","3":"baz","4":"blong"}"
删除一个连续数组值的方式产生的非连续数组
array(3) {
[0]=>
string(3) "foo"
[2]=>
string(3) "baz"
[3]=>
string(5) "blong"
}
string(33) "{"0":"foo","2":"baz","3":"blong"}"
注释
Note:
如果执行失败，可以通过 json_last_error() 函数来获取详细错误信息。
Note:
如果要编码的数组的键不是从0开始的数字，所有的键将会被当作字符串，并明确声明为 key-value 对。
参见
JsonSerializable json_decode() - 对 JSON 格式的字符串进行编码 json_last_error() - 返回最后发生的错误
