php获取指定数量随机字符串的方法

functiongetARandLetter($number= 1) {

  if($number== 0)

    returnFALSE;//去除0

  $number=$number< 0 ? -$number:$number;//如果小于零取正值

  $letterArr=array('A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P','Q','R','S','T','U','V','W','X','Y','Z','a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z');

  $returnStr=''

  for($i= 0;$i<$number;$i++) {

    $returnStr.=$letterArr[rand ( 0, 51 )];

  }

  return$returnStr;

}

echogetARandLetter(8);

/*加密解密*/

functionauthcode($string,$operation='E') {

  $ssl_public=file_get_contents(DATA_PATH."/conf/cert_public.key");

  $ssl_private=file_get_contents(DATA_PATH."/conf/cert_private.pem");

  $pi_key= openssl_pkey_get_private($ssl_private);//这个函数可用来判断私钥是否是可用的，可用返回资源id Resource id

  $pu_key= openssl_pkey_get_public($ssl_public);//这个函数可用来判断公钥是否是可用的

  if(false == ($pi_key||$pu_key))return'证书错误';

  $data="";

  if($operation=='D'){

    openssl_private_decrypt(base64_decode($string),$data,$pi_key);//私钥解密

  }else{

    openssl_public_encrypt($string,$data,$pu_key);//公钥加密

    $data=base64_encode($data);

  }

  return$data;

}

/*生成证书*/

functionexportOpenSSLFile(){

  $config=array(

    "digest_alg"   =>"sha512",

    "private_key_bits"=> 4096,          //字节数  512 1024 2048  4096 等

    "private_key_type"=> OPENSSL_KEYTYPE_RSA,  //加密类型

  );

  $res= openssl_pkey_new($config);

  if($res== false)returnfalse;

  openssl_pkey_export($res,$private_key);

  $public_key= openssl_pkey_get_details($res);

  $public_key=$public_key["key"];

  file_put_contents(DATA_PATH."/conf/cert_public.key",$public_key);

  file_put_contents(DATA_PATH."/conf/cert_private.pem",$private_key);

  openssl_free_key($res);

}

<?php

$mysqli=newmysqli("localhost","my_user","my_password","world");

$uresult=$mysqli->query("SELECT Name FROM City", MYSQLI_USE_RESULT);

if($uresult) {

  while($row=$uresult->fetch_assoc()) {

    echo$row['Name'] . PHP_EOL;

  }

}

$uresult->close();

<?php

$pdo=newPDO("mysql:host=localhost;dbname=world",'my_user','my_pass');

$pdo->setAttribute(PDO::MYSQL_ATTR_USE_BUFFERED_QUERY, false);

$uresult=$pdo->query("SELECT Name FROM City");

if($uresult) {

  while($row=$uresult->fetch(PDO::FETCH_ASSOC)) {

    echo$row['Name'] . PHP_EOL;

  }

}

<?php

$conn= mysql_connect("localhost","my_user","my_pass");

$db = mysql_select_db("world");

$uresult= mysql_unbuffered_query("SELECT Name FROM City");

if($uresult) {

  while($row= mysql_fetch_assoc($uresult)) {

    echo$row['Name'] . PHP_EOL;

  }

}