Question

我之前问过一个问题，这个问题都围绕着一个JSON格式问题。我有一个PHP页面，它只是从MYSQL数据库中获取行，并返回它们。但是，我不确定如何格式化它们所以我得到的所有列都是一个集合，并且对于每一行，它创建一个新集合。我不确定对这样的事情进行编码的常见做法是什么。

e.g。这就是我想要的（如果它是正确的）：

{ "message": [
   {
      "chat":"Hello, world!",
      "time":"2014-05-09 17:32:00",
       "username":"Josue"
   },
   {
      "chat":"This is my second message.",
      "time":"2014-05-09 17:32:05",
      "username":"Josue"
   }
]
}

这样，我可以使用$ .parseAJAX解析，并访问我的数据，如：data.message[0].chat，它将返回“Hello world！”。

以下是我目前正在做的事情：

$SQL = sprintf('SELECT time_sent, chat, username FROM Messages where time_sent >= date(\'%s\')', $last_chat_time);
$result = mysql_query($SQL);

$messages = Array();

while ( $row = mysql_fetch_assoc($result) ) {
    $messages[] = 'chat';
    $messages[] = $row['chat'];
    $messages[] = 'time';
    $messages[] = $row['time_sent'];
    $messages[] = 'username';
    $messages[] = $row['username'];
}

$loopCount = count($chats);

if(count($messages) > 0){
/*
    $sexyJSON = '{message: [';
    for($i = 0; $i < $loopCount; $i++){
        $sexyJSON .= '{"chat":"'.$chats[$i].'","time":"'.$times[$i].'","username":"'.$usernames[$i].'"},';
    }
    $sexyJSON = substr($sexyJSON,0,strlen($sexyJSON)-1);
    $sexyJSON .= ']}';
    $newMessages = $sexyJSON;
    echo $sexyJSON;
    */

     echo json_encode($messages);
}

当我简单地编码我的数组时，它会返回如下内容：

["chat","Hello, world!","time","2014-05-09 17:32:00","username","Josue","chat","hmmm","time","2014-05-09 17:48:34","username","asdf"]

我需要做些什么才能将消息分组聊天，日期与日期以及用户名在键值对中？

Answer 1

mysql_fetch_assoc的格式应为

array('chat'=>'Some chat', 'time_sent'=>'123456', 'username'=>'abcdefg')

json_encode会直接将其转换为

{"chat":"Some chat", "time_sent":"123456", "username":"abcdefg"}

所以在你的循环中，如果你只是按$mesages[] = $row;并按原样保留你的json_encode，它应该如上所示工作。但是，您可以更改SQL语句以为列提供别名，以便time_sent只显示属性time

Answer 2

这就是我要做的事情：

$SQL = sprintf('SELECT time_sent, chat, username FROM Messages where time_sent >= date(\'%s\')', $last_chat_time);
$result = mysql_query($SQL);

$messages = array();

while ( $row = mysql_fetch_assoc($result) ) {
  $arr = array();
  $arr['chat'] = $row['chat'];
  $arr['time'] = $row['time_sent'];
  $arr['username'] = $row['username'];
  $messages[] = $arr;
}

$loopCount = count($chats);

if(count($messages) > 0){
    echo json_encode($messages);
}

如果没有编码，将输出：

Array
(
    [0] => Array
        (
            [chat] => chat_0
            [time] => time_sent_0
            [username] => username_0
        )

    [1] => Array
        (
            [chat] => chat_1
            [time] => time_sent_1
            [username] => username_1
        )

    [2] => Array
        (
            [chat] => chat_2
            [time] => time_sent_2
            [username] => username_2
        )

    [3] => Array
        (
            [chat] => chat_3
            [time] => time_sent_3
            [username] => username_3
        )

）

如果编码：

[{"chat":"chat_0","time":"time_sent_0","username":"username_0"},
 {"chat":"chat_1","time":"time_sent_1","username":"username_1"},
 {"chat":"chat_2","time":"time_sent_2","username":"username_2"},
 {"chat":"chat_3","time":"time_sent_3","username":"username_3"}]

解析JSON

假设您将JSON结果放在data var

中

var obj = $.parseJSON(data);

$.each(obj, function(i, value){
    console.log(value.chat);    
});

Answer 3

您需要使用多维数组才能使其正常工作。下面的代码已经过编辑，可以为命名索引赋值，并将这些值附加到$ messages数组的第二级。

$messages = Array();

while ( $row = mysql_fetch_assoc($result) ) {
    $messages[] = Array(
        'chat' => $row['chat'],
        'time' => $row['time_sent'],
        'username' => $row['username']
    );
}

Answer 4

while循环应该是这样的：

while ( $row = mysql_fetch_assoc($result) ) {
  $arr = array();
  $arr['chat'] = $row['chat'];
  $arr['time'] = $row['time_sent'];
  $arr['username'] = $row['username'];
  $messages[] = $arr;
}

Answer 5

通过在SQL中获取字段名称来节省一点时间。

$SQL = sprintf('SELECT time_sent as `time`, chat, username FROM Messages where time_sent >= date(\'%s\')', $last_chat_time);
$result = mysql_query($SQL);

$messages = array();

while ($row = mysql_fetch_assoc($result)) {
  $messages[] = $row;
}

echo json_encode($messages);

IMO在没有消息的情况下返回一个空数组比返回任何消息要好，因为现在你可以在JavaScript代码中区分你的php是否有效，如果你没有消息。

如何正确格式化JSON

5 个答案: