[Technical Advancement] How to import and export CSV files with PHP

We first prepare the mysql data table. Assume that there is a table student in the project that records student information, and has id, name, sex, age to record the student's name, gender, age and other information respectively.

CREATE TABLE `student` ( 
  `id` int(11) NOT NULL auto_increment, 
  `name` varchar(50) NOT NULL, 
  `sex` varchar(10) NOT NULL, 
  `age` smallint(3) NOT NULL default '0', 
  PRIMARY KEY  (`id`) 
) ENGINE=MyISAM  DEFAULT CHARSET=utf8;

We also need an html interactive page to place the import form and export button.

<form id="addform" action="do.php?action=import" method="post" enctype="multipart/form-data"> 
    <p>请选择要导入的CSV文件：<br/><input type="file" name="file"> <input type="submit" 
    class="btn" value="导入CSV"> 
    <input type="button" class="btn" value="导出CSV" onclick="window.location.href=&#39;do.php? 
    action=export&#39;"></p> 
</form>

After selecting the local csv file, click Import and submit it to do.php?action=import for processing, and click the Export button to request the address do.php?action=export for data export processing.

Import CSV

do.php needs to process the import and export processes separately according to the parameters obtained. The PHP structure is as follows:

include_once ("connect.php"); //连接数据库 
 
$action = $_GET['action']; 
if ($action == 'import') { //导入CSV 
   //导入处理 
} elseif ($action=='export') { //导出CSV 
   //导出处理 
}

Import CSV processing process: verify csv File legality (ignored in this article) ->Open to read and parse the fields in the csv file

->Loop to obtain the values ​​of each field->Add to the data table in batches->Complete.

if ($action == 'import') { //导入CSV 
    $filename = $_FILES['file']['tmp_name']; 
    if (empty ($filename)) { 
        echo '请选择要导入的CSV文件！'; 
        exit; 
    } 
    $handle = fopen($filename, 'r'); 
    $result = input_csv($handle); //解析csv 
    $len_result = count($result); 
    if($len_result==0){ 
        echo '没有任何数据！'; 
        exit; 
    } 
    for ($i = 1; $i < $len_result; $i++) { //循环获取各字段值 
        $name = iconv(&#39;gb2312&#39;, &#39;utf-8&#39;, $result[$i][0]); //中文转码 
        $sex = iconv(&#39;gb2312&#39;, &#39;utf-8&#39;, $result[$i][1]); 
        $age = $result[$i][2]; 
        $data_values .= "(&#39;$name&#39;,&#39;$sex&#39;,&#39;$age&#39;),"; 
    } 
    $data_values = substr($data_values,0,-1); //去掉最后一个逗号 
    fclose($handle); //关闭指针 
    $query = mysql_query("insert into student (name,sex,age) values $data_values");//批量插入数据表中 
    if($query){ 
        echo &#39;导入成功！&#39;; 
    }else{ 
        echo &#39;导入失败！&#39;; 
    } 
}

Note that PHP’s own fgetcsv function can easily handle csv. Use this function to read a line from the file pointer and parse the CSV field. The function below parses the csv file fields and returns them as an array.

function input_csv($handle) { 
    $out = array (); 
    $n = 0; 
    while ($data = fgetcsv($handle, 10000)) { 
        $num = count($data); 
        for ($i = 0; $i < $num; $i++) { 
            $out[$n][$i] = $data[$i]; 
        } 
        $n++; 
    } 
    return $out; 
}

In addition, when importing into the database, we use batch insertion instead of inserting one by one, so when constructing the SQL statement, we need to do a little processing, see the code.

Export CSV

We know that csv file is a plain text file composed of comma delimiters. You can open it with excel, and the effect is the same as xls table.

Export CSV processing flow: Read the student information table->loop records to construct comma-separated field information->set header information->Export the file (download) to local.

... 
} elseif ($action=='export') { //导出CSV 
    $result = mysql_query("select * from student order by id asc"); 
    $str = "姓名,性别,年龄\n"; 
    $str = iconv('utf-8','gb2312',$str); 
    while($row=mysql_fetch_array($result)){ 
        $name = iconv('utf-8','gb2312',$row['name']); //中文转码 
        $sex = iconv('utf-8','gb2312',$row['sex']); 
        $str .= $name.",".$sex.",".$row['age']."\n"; //用引文逗号分开 
    } 
    $filename = date('Ymd').'.csv'; //设置文件名 
    export_csv($filename,$str); //导出 
}

To export the data to local, you need to modify the header information, the code is as follows:

function export_csv($filename,$data) { 
    header("Content-type:text/csv"); 
    header("Content-Disposition:attachment;filename=".$filename); 
    header('Cache-Control:must-revalidate,post-check=0,pre-check=0'); 
    header('Expires:0'); 
    header('Pragma:public'); 
    echo $data; 
}

Pay attention to the import and export process, because we use unified UTF-8 encoding , be sure to remember to transcode when encountering Chinese characters, otherwise the Chinese characters may be garbled.

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