PHP connects to MySQL database and outputs it in json format
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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
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
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
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
[{"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
Array ( [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。
function encode_json($arr){
$code = json_encode($arr);
return preg_replace("#\\\u([0-9a-f]+)#ie", "iconv('UCS-2', 'UTF-8', pack('H4', '\\1'))", $code);
}方法2：先对需要处理的做urlencode处理，然后json_encode，最后做urldecode处理
function encode_json($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;
}mysqli连接mysql数据库的常用方法（面向对象和面向过程）
相信开始学习PHP的伙伴们用的都是php4,或者php5，在这些版本中都有一个连接数据库的函数mysql_connect（），但在使用php5.5及5.5以上版本时，你会发现使用mysql_connect()会直接报错，这是因为php5.5以后的版本考虑到未来的可移植性和安全性，性能而废弃了mysql_connect（）函数，所以我们只能使用mysqli_connect()和PDO，这里我说一下mysqli_connect（）。
mysqli_connect()的两种方式，面向过程和面向对象的连接数据库方法。
（1）面向过程连接数据库：
<!-- 面向过程的数据库mysqli连接 -->
<?php
$conn=mysqli_connect("localhost","root","950609","user");
// 连接数据库user
if (!$conn) {
# code...判断链接是否成功
echo "连接失败！";
echo mysqli_connect_error();
exit();
}
mysqli_query($conn,"set names utf8");
// 指定编码格式
$sql="select * from goods";
// sql语句
$result=mysqli_query($conn,$sql);
// 执行sql语句，将执行结果返回到结果集中
$row=mysqli_fetch_array($result);
// 从结果集中取得一行作为数组
echo "<pre class="brush:php;toolbar:false">";
print_r($row);
?>（2）面向对象的数据库连接
<!-- 面向对象的数据库mysqli连接 -->
lt;?php
$mysqli=new mysqli("localhost","root","950609","user");
if ( $mysqli -> connect_error ) {
die( 'Connect Error (' . $mysqli -> connect_errno . ') '
. $mysqli -> connect_error );
}
$sql = "select * from goods";
$mysqli->set_charset("utf8");
$result = $mysqli->query($sql);
$row = $result->fetch_array(); // 从结果集中取得一行作为数组
echo '<pre class="brush:php;toolbar:false">';
print_r($row);
/* free result set */
$result->free();
/* close connection */
$mysqli->close();
>这篇文章就介绍到这了，关于PHP连接MySQL数据库并以json格式输出的实现代码，需要的朋友可以参考一下。
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