json_decode 和 json_encode 区别

json_decode： json字符串转json对象
json_encode： json对象转json字符串
 
json对象：

{
    "id": 68,
    "order_no": "C615901108975467",
    "snap_items": [
        {
            "id": 1,
            "name": "芹菜 半斤",
        },
        {
            "id": 2,
            "name": "梨花带雨 3个",
        }
    ]
}

json字符串

{
    "id": 68,
    "order_no": "C615901108975467",
    "snap_items": "[
        {\"id\":1,\"name\":\"\\u82b9\\u83dc \\u534a\\u65a4\"},
        {\"id\":2,\"name\":\"\\u68a8\\u82b1\\u5e26\\u96e8 3\\u4e2a\"}
    ]",
}