json_encode规范些

1，json输出 

<?php
class JsonOutput
{
   // 返回结果code值
   private $retCode = 0;
   // 返回信息
   private $retMsg = '';
   // 返回结果数据
   private $retData = null;
   // 返回结果附加数据
   private $retInfo = null;
   // 返回json的键
   private $retKeys = array(
      'code' => 'code',
      'msg'  => 'message',
      'data' => 'data',
      'info' => 'info');
   // 输出json后是否exit，默认true
   private $exit = true;
   // 不转义斜杠
   private $unEscapedSlashes = true;
   // 不转义unicode
   private $unEscapedUnicode = true;
   private $instance;

   /**
    * JsonOutput constructor.
    * @param int $codeDefault 默认返回成功code值
    * @param array $keys 返回json键名，如array('code'=>'retCode','msg'=>'message')
    */
   public function __construct($codeDefault = 0, $keys = array())
   {
      if (!$this->instance) {
         $this->instance = $this;
      }
      $this->retCode = $codeDefault;
      foreach ($this->retKeys as $key => $value) {
         if (isset($keys[$key]) && !empty($keys[$key])) {
            $this->retKeys[$key] = $keys[$key];
         }
      }
   }

   /**
    * 设置输出结果的code
    * @param int $code code
    * @param string $key code的键名
    * @return JsonOutput
    */
   public function code($code = 1, $key = '')
   {
      $this->retCode = $code;
      $this->retKeys['code'] = empty($key) ? $this->retKeys['code'] : $key;
      return $this->instance;
   }

   /**
    * 设置输出结果的msg
    * @param string $msg msg
    * @param string $key msg的键名
    * @return JsonOutput
    */
   public function msg($msg = '', $key = '')
   {
      $this->retMsg = $msg;
      $this->retKeys['msg'] = empty($key) ? $this->retKeys['msg'] : $key;
      return $this->instance;
   }

   /**
    * 设置输出结果的data
    * @param null $data data
    * @param string $key data的键名
    * @return JsonOutput
    */
   public function data($data = null, $key = '')
   {
      $this->retData = $data;
      $this->retKeys['data'] = empty($key) ? $this->retKeys['data'] : $key;
      return $this->instance;
   }

   /**
    * 设置输出结果的info
    * @param null $info info
    * @param string $key info的键名
    * @return JsonOutput
    */
   public function info($info = null, $key = '')
   {
      $this->retInfo = $info;
      $this->retKeys['info'] = empty($key) ? $this->retKeys['info'] : $key;
      return $this->instance;
   }

   /**
    * 设置输出json后是否exit
    * @param bool $exit 默认true，即输出json后exit
    * @return JsonOutput
    */
   public function isExit($exit = true)
   {
      $this->exit = $exit;
      return $this->instance;
   }

   /**
    * 设置是否不转义斜杠（仅在php >= 5.4）
    * @param bool $flg 默认true，不转义斜杠
    * @return JsonOutput
    */
   public function unEscapedSlashes($flg = true)
   {
      $this->unEscapedSlashes = $flg;
      return $this->instance;
   }

   /**
    * 设置是否不转义unicode（仅在php >= 5.4）
    * @param bool $flg 默认true，不转义unicode
    * @return JsonOutput
    */
   public function unEscapedUnicode($flg = true)
   {
      $this->unEscapedUnicode = $flg;
      return $this->instance;
   }

   /**
    * 输出json
    */
   public function out()
   {
      $data = array(
         $this->retKeys['code'] => $this->retCode,
         $this->retKeys['msg']  => $this->retMsg,
         $this->retKeys['data'] => $this->retData,
         $this->retKeys['info'] => $this->retInfo
      );

      $options = 0;
      if (defined('JSON_UNESCAPED_SLASHES') && $this->unEscapedSlashes) {
         $options = $options | JSON_UNESCAPED_SLASHES;
      }
      if (defined('JSON_UNESCAPED_UNICODE') && $this->unEscapedUnicode) {
         $options = $options | JSON_UNESCAPED_UNICODE;
      }

      if ($this->isIE()) {
         header('Content-type: text/html;charset=UTF-8');
      } else {
         header('Content-type: application/json;charset=UTF-8');
      }

      if ($options != 0) {
         echo json_encode($data, $options);
      } else {
         echo json_encode($data);
      }
      $this->exit && exit();
   }

   /**
    * @return bool|int
    */
   private function isIE()
   {
      $isIE = strpos($_SERVER['HTTP_USER_AGENT'], "Triden");
      return $isIE;
   }
}

2，使用：include_once 引入上述文件：

$Json = new JsonOutput(1, array('msg' => 'msg'));// 操作成功，错误代码为0，否则大于0
$Json->code(0)->msg('成功')->data->($data)->info()->out();

  注意：$data 是数据库查询的数据

上述等同于

result = array(
    'code'=>0,
    'msg'=>'成功',
    'data'=>$data,
    'info'=>'分页，url等信息'  // 或者自定义
);
echo json_encode($result);
die;