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1.简介
PHP连接数据库有多种方法,现介绍常用的MySQL数据库连接方法,PHP连接MySQL也有两种方式,一是面向对象,二是面向过程方式,两种方法稍有区别。下面通过代码介绍两种方法连接MySQL并以json格式输出。
2、面向对象方式
[php] view plain copy<?php header("content-Type: text/html; charset=utf-8");//字符编码设置 $servername = "localhost"; $username = "root"; $passWord = "123456"; $dbname = "mydb"; // 创建连接 $conn =new mysqli($servername, $username, $password, $dbname); // 检测连接 if ($conn->connect_error) { die("Connection failed: " . $conn->connect_error); } $sql = "SELECT * FROM power WHERE DATE='2014-1-1'"; $result = $conn->query($sql); $arr = array(); // 输出每行数据 while($row = $result->fetch_assoc()) { $count=count($row);//不能在循环语句中,由于每次删除row数组长度都减小 for($i=0;$i<$count;$i++){ unset($row[$i]);//删除冗余数据 } array_push($arr,$row); } //PRint_r($arr); echo json_encode($arr,JSON_UNESCAPED_UNICODE);//json编码 $conn->close(); ?> 3.面向过程方式[php] view plain copy<?php header("content-Type: text/html; charset=utf-8");//字符编码设置 $servername = "localhost"; $username = "root"; $password = "123456"; $dbname = "mydb"; // 创建连接 $con =mysqli_connect($servername, $username, $password, $dbname); // 检测连接 if (mysqli_connect_errno()) { echo "Failed to connect to MySQL: " . mysqli_connect_error(); } $sql = "SELECT * FROM power WHERE DATE='2014-1-1'"; $result = mysqli_query($con,$sql); $arr = array(); while($row = mysqli_fetch_array($result)) { $count=count($row);//不能在循环语句中,由于每次删除 row数组长度都减小 for($i=0;$i<$count;$i++){ unset($row[$i]);//删除冗余数据 } array_push($arr,$row); } echo json_encode($arr,JSON_UNESCAPED_UNICODE); mysqli_close($con); ?> 4.输出json示例[javascript] view plain copy[{"NAME":"小区1","DM":"A","LNG":"564142.623","LAT":"4329376.169","DATE":"2014-1-1","VAL":"26.8"},{"NAME":"小区2","DM":"B","LNG":"563089.677","LAT":"4329311.017","DATE":"2014-1-1","VAL":"26.8"}] 5.json输出说明由于$row = mysqli_fetch_array($result)获取数据的一行数据并以数组形式存储,里边除了字段和值键值对外默认还会有0,1,2……下标存在,如下所示
[Javascript] view plain copyArray ( [0] => 小区1 [NAME] => 小区1 [1] => A [DM] => A [2] => 564142.623 [LNG] => 564142.623 [3] => 4329376.169 [LAT] => 4329376.169 [4] => 2014-1-1 [DATE] => 2014-1-1 [5] => 26.8 [VAL] => 26.8 ) 如此数据就出现冗余,unset方法则是删除数组冗余数据,之后再添加到$arr数组中。另外在json编码中json_encode($arr);会出现中文被unicode编码,php5.3加入了options参数, 5.4以后才加入JSON_UNESCAPED_UNICODE,这个参数,不需要做escape和unicode处理。所以在5.4之前都需要对中文做个处理 。5.4里面直接补上代码中的参数即可。
整理网上的方法,5.4之前处理方法有两种,方法1:在实际应用中有个问题,部分字符会掉,原因暂不清楚。
[php] view plain copyfunction encode_json($arr){ $code = json_encode($arr); return preg_replace("#///u([0-9a-f]+)#ie", "iconv('UCS-2', 'UTF-8', pack('H4', '//1'))", $code); }方法2:先对需要处理的做urlencode处理,然后json_encode,最后做urldecode处理
[php] view plain copyfunction encode_json($str) { return urldecode(json_encode(url_encode($str))); } /** * */ function url_encode($str) { if(is_array($str)) { foreach($str as $key=>$value) { $str[urlencode($key)] = url_encode($value); } } else { $str = urlencode($str); } return $str; }新闻热点
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