無法重定向後mysqli連接錯誤

Question

我是新來的PHP。我試圖重定向到php中的錯誤頁面，當我得到一個MySQL連接錯誤，但我得到一個錯誤，指出我不能修改頭，因爲輸出已經在第8行（我創建連接）發送。請你能建議這樣做的正確方法嗎？

<?php 
$servername = "localhost:3306"; 
$username = "danny"; 
$password = "sql1"; 
$dbname = "testdb"; 

    try{ 
     $conn = new mysqli($servername, $username, $password, $dbname); 
    } 
    catch(Exception $e){ 
    header('Location: /connection_error.php'); 
    die(); 
} 


?> 

感謝

丹尼

Answer 1

你需要在頂部加入這一行告訴mysqli的拋出異常

mysqli_report(MYSQLI_REPORT_STRICT); 
$servername = "localhost:3306"; 
$username = "danny"; 
$password = "sql1"; 
$dbname = "testdb"; 

    try{ 
     $conn = new mysqli($servername, $username, $password, $dbname); 
    } 
    catch(Exception $e){ 
    header('Location: /connection_error.php'); 
    die(); 
} 

Answer 2

試試這個

<?php 
ob_start(); 

$servername = "localhost:3306"; 
$username = "danny"; 
$password = "sql1"; 
$dbname = "testdb"; 

    try{ 
     $conn = new mysqli($servername, $username, $password, $dbname); 
    } 
    catch(Exception $e){ 
    header('Location: /connection_error.php'); 
} 

ob_flush(); 
?> 

Answer 3

此外，你總是可以檢查th e使用mysqli::$connect_errno從上次連接呼叫發出的錯誤代碼，但如果失敗，則會返回上次呼叫的錯誤代碼值。零意味着沒有錯誤發生（因此錯誤）。

<?php 
    /* Variable Defaults */ 
    $servername = 'localhost:3306'; 
    $username = 'danny'; 
    $password = 'sql1'; 
    $dbname  = 'testdb'; 

    /* Make Connection */ 
    $conn = new mysqli($servername, $username, $password, $dbname); 

    /* Check Connection */ 
    if($conn->connect_errno) { 
     /* Redirect */ 
     header('Location: /connection_error.php'); 
     exit(); 
    } 
?>