Laravel5.* 打印出执行的sql语句的方法

// 先引入DB 
use DB;
// 或者直接使用 \DB::
 DB::listen(function($sql, $bindings, $time) {
        dump($sql);
      });

use DB;
// 或者直接使用 \DB::
// 只能接受一个参数

QueryExecuted {#84 ?
 +sql: "select * from `posts` where `slug` = ? limit 1"
 +bindings: array:1 [▶]
 +time: 0.59
 +connection: MySqlConnection {#85 ▶}
 +connectionName: "mysql"
}

 DB::listen(function($sql) {
        dump($sql);
        // echo $sql->sql;
        // dump($sql->bindings);
      });

// 如果要放入日志文件中
DB::listen(
  function ($sql) {
    // $sql is an object with the properties:
    // sql: The query
    // bindings: the sql query variables
    // time: The execution time for the query
    // connectionName: The name of the connection

    // To save the executed queries to file:
    // Process the sql and the bindings:
    foreach ($sql->bindings as $i => $binding) {
      if ($binding instanceof \DateTime) {
        $sql->bindings[$i] = $binding->format('\'Y-m-d H:i:s\'');
      } else {
        if (is_string($binding)) {
          $sql->bindings[$i] = "'$binding'";
        }
      }
    }

    // Insert bindings into query
    $query = str_replace(array('%', '?'), array('%%', '%s'), $sql->sql);

    $query = vsprintf($query, $sql->bindings);

    // Save the query to file
    $logFile = fopen(
      storage_path('logs' . DIRECTORY_SEPARATOR . date('Y-m-d') . '_query.log'),
      'a+'
    );
    fwrite($logFile, date('Y-m-d H:i:s') . ': ' . $query . PHP_EOL);
    fclose($logFile);
  }
);