json_encode 编码与参数

JSON 编码

知识概述

json 数据格式：主要由对象 { } 和数组 [ ] 组成:

其中对象包括键值对（属性: 属性值）{key:value}，value 可为 str，num，list，obj；

取值以 objcet.key 获取；

对象 {key:value, key2:value2,} 键 : 值 以 冒号分开，对间 以 , 连接；

数组包含元素：str，num，list，obj 都可以，利用索引访问 [index]，用 . 连接各个值。

数组

var stu = {
	"student":
		[
			{"name": "Tom","Grade":1, "age":11, "gender": "M"},
			{"name": "Jerry", "Grade":1, "age":10, "gender": "M"}
		],
	"position": 
		{"class1": "room1", "class2": "room2"}
};

取值

document.write(stu.student[1].name);    // 输出第二个学生名 "Jerry"
document.write(stu.student[0].age);     // 输出第一个学生年龄 "11"
document.write(stu.position.class1);    // 输出 position 的 class1 值 "room1"
document.write(stu["position"].class2); // 同时支持中括号键访问对象值 "room2"

类型简述

json_encode 编码常见用于索引类型和关联类型数组。

其中索引类型又分为数组 ["val1","val2",...] 和对象 {"0":"one","1":"two",...}，从 0 开始为每个对象索引序号；

而关联类型为可以为数值指定名称 {"KR":"Korea","JP":"Japan","SG":"Singapore"}，可以更直观判断值的对应关系。

索引数组

默认仅以数组形式输出

$arr = Array('one', 'two', 'three');
echo json_encode($arr);

输出结果 https://static.hexingxing.cn/v2/example/jsonext/JSON_ARRAY_ONLY_VALUE/

格式：[]

["one","two","three"]

索引对象

JSON_FORCE_OBJECT 强制转换为对象输出

$arr = Array('one', 'two', 'three');
echo json_encode($arr,JSON_FORCE_OBJECT);

输出结果 https://static.hexingxing.cn/v2/example/jsonext/JSON_ARRAY_INDEX/

格式：{}

{"0":"one","1":"two","2":"three"}

关联数组

$arr = Array('KR'=>'Korea', 'JP'=>'Japan', 'SG'=>'Singapore');
echo json_encode($arr);

输出结果 https://static.hexingxing.cn/v2/example/jsonext/JSON_ARRAY_ASSOCIATIVE/

格式：{}

{"KR":"Korea","JP":"Japan","SG":"Singapore"}

对象转换

$obj->body           = 'another post';
$obj->id             = 21;
$obj->approved       = true;
$obj->favorite_count = 1;
$obj->status         = NULL;
echo json_encode($obj,JSON_PRETTY_PRINT);

输出结果 https://static.hexingxing.cn/v2/example/jsonext/JSON_ARRAY_OBJECT_CONVERSION/

格式：{}

{
　"body":"another post",
　"id":21,
　"approved":true,
　"favorite_count":1,
　"status":null
}

JSON 参数

JSON_PRETTY_PRINT 格式化输出
JSON_FORCE_OBJECT 强制转换为对象
JSON_UNESCAPED_UNICODE 支持中文字符

默认数组形式

$水果 = [
    "苹果",
    "西瓜",
    "香蕉"
];

header('Content-type:application/json;charset=utf-8');
  echo json_encode($水果);//默认

["\u82f9\u679c","\u897f\u74dc","\u9999\u8549"]

https://static.hexingxing.cn/v2/example/jsonext/JSON_NONE/

格式化输出对象

$水果 = [
    "a"=>"苹果",
    "b"=>"西瓜",
    "c"=>"香蕉"
];

header('Content-type:application/json;charset=utf-8');
  echo json_encode($水果, JSON_PRETTY_PRINT);//格式化输出对象

{
    "a": "\u82f9\u679c",
    "b": "\u897f\u74dc",
    "c": "\u9999\u8549"
}

https://static.hexingxing.cn/v2/example/jsonext/JSON_PRETTY_PRINT/

强制转换为对象

$水果 = [
    "苹果",
    "西瓜",
    "香蕉"
];

header('Content-type:application/json;charset=utf-8');
  echo json_encode($水果, JSON_FORCE_OBJECT);//强制转换为对象

{"0":"\u82f9\u679c","1":"\u897f\u74dc","2":"\u9999\u8549"}

https://static.hexingxing.cn/v2/example/jsonext/JSON_FORCE_OBJECT/

支持显示中文字符

$水果 = [
    "a"=>"苹果",
    "b"=>"西瓜",
    "c"=>"香蕉"
];

header('Content-type:application/json;charset=utf-8');
  echo json_encode($水果, JSON_UNESCAPED_UNICODE);//支持显示中文字符

{"a":"苹果","b":"西瓜","c":"香蕉"}

https://static.hexingxing.cn/v2/example/jsonext/JSON_UNESCAPED_UNICODE/

格式化输出并支持中文字符

$水果 = [
    "a"=>"苹果",
    "b"=>"西瓜",
    "c"=>"香蕉"
];

header('Content-type:application/json;charset=utf-8');
  echo json_encode($水果, JSON_PRETTY_PRINT|JSON_UNESCAPED_UNICODE);//格式化输出并支持中文字符

{
    "a": "苹果",
    "b": "西瓜",
    "c": "香蕉"
}

https://static.hexingxing.cn/v2/example/jsonext/JSON_PRETTY_PRINT&JSON_UNESCAPED_UNICODE/