php返回json数据

一、返回格式为：

[
    {"id":"1","address":"IANA"},
    {"id":"2","address":"美国"}
]

php代码：

php
    header('Content-Type:application/json');  //此声明非常重要
    try {
        $conn = new PDO("mysql:host=localhost;dbname=orig", 'admin', 'admin');
        $conn -> setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
        $conn->exec("SET NAMES utf8");   //设置编码
    } catch(PDOException $e) {
        echo "conn_error:
" . $e -> getMessage();
    }

    $sql = "select id,address from ip_segments limit 2;";

    $result = $conn->query($sql)->fetchAll(PDO::FETCH_ASSOC);

    echo json_encode($result,JSON_UNESCAPED_UNICODE);  //JSON_UNESCAPED_UNICODE防止中文乱码
?>

二、返回格式为：

{
    "total":2,
    "rows":[
        {"id":"1","address":"IANA"},
        {"id":"2","address":"美国"}
    ]
}

php代码：

    header('Content-Type:application/json');
    try {
        $conn = new PDO("mysql:host=localhost;dbname=orig", 'admin', 'admin');
        $conn -> setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
        $conn->exec("SET NAMES utf8");
    } catch(PDOException $e) {
        echo "conn_error:
" . $e -> getMessage();
    }

    $sql = "select id,address from ip_segments limit 2;";

    $result = $conn->query($sql)->fetchAll(PDO::FETCH_ASSOC);

    $json['total'] = count($result);
    $json['rows'] = $result;

    echo json_encode($json,JSON_UNESCAPED_UNICODE);
?>