在 PHP 上解析 JSON 并提取特定值

Question

目标：解析后面的 json 字符串并单独获取提到的值，稍后将这些分离的值插入到 mysql 数据库。
我在JsonLint 上检查了我的json 字符串

1. 用户名，
2. 选定日期，
3. selected_project，

4. tasks , 4.1.task_name, 4.2 work_hours

   {
   "user_name": "USER",
   "selected_date": "2015-06-08",
   "selected_project": "Project1",
   "tasks": [
       {
           "task_name": "task-1",
           "work_hours": [
               {
               "Monday": " 3"
               },
               {
               "Tuesday": " 0"
               },
               {
               "Wednesday": " 2.5"
               },
               {
               "Thursday": " 2"
               },
               {
               "Friday": " 0"
               },
               {
               "Saturday": " 0"
               },
               {
               "Sunday": " 0"
               }
           ]
       }
   ] 
   }
   

   PHP代码是：

   $str_json = file_get_contents('php://input'); //($_POST doesn't work here)
   $response = json_decode($str_json, true); // decoding received JSON to array
   $jsonIterator = new RecursiveIteratorIterator(
   new RecursiveArrayIterator(json_decode($response, TRUE)),
   RecursiveIteratorIterator::SELF_FIRST);
   foreach ($jsonIterator as $key => $val) 
   {
    if(is_array($val)) 
    {
      echo "$key:\n";
    } 
    else 
    {
      echo "$key => $val\n";
      echo "$value";
    }
   }
   

由于我是 JSON 和 PHP 的新手，我无法解决这个问题，我们将不胜感激。

Answer 1

    <?
$json = '{
"user_name": "USER",
"selected_date": "2015-06-08",
"selected_project": "Project1",
"tasks": [
    {
        "task_name": "task-1",
        "work_hours": [
            {
            "Monday": " 3"
            },
            {
            "Tuesday": " 0"
            },
            {
            "Wednesday": " 2.5"
            },
            {
            "Thursday": " 2"
            },
            {
            "Friday": " 0"
            },
            {
            "Saturday": " 0"
            },
            {
            "Sunday": " 0"
            }
        ]
    }
] 
}';

// decode your json  into associative arrays
$decoded = json_decode($json, true);

// use array
echo "Username: ". $decoded['user_name'] . "<br>";
echo "Date: ". $decoded['selected_date'] . "<br>";
echo "project: ". $decoded['selected_project'] . "<br>";
echo "Task: ". $decoded['tasks'][0]['task_name'] . "<br>";

foreach($decoded['tasks'][0]['work_hours'] as $key => $value) {
    foreach($value as $key2 => $value2){
        echo $key2 . ": ". $value2 . "<br>";
    }
}
?>