什麼是 PHP 中的異常處理?
異常是在程式執行期間出現的問題。在程式執行過程中,當發生異常時,語句後面的程式碼將不會執行,PHP 將嘗試查詢第一個匹配的 catch 塊。如果未捕獲異常,則會發出帶有“未捕獲異常”的 PHP 致命錯誤。
語法
try {
print "this is our try block";
throw new Exception();
}catch (Exception $e) {
print "something went wrong, caught yah! n";
}finally {
print "this part is always executed";
}示例
<?php
function printdata($data) {
try {
//If var is six then only if will be executed
if($data == 6) {
// If var is zero then only exception is thrown
throw new Exception('Number is six.');
echo "
After throw (It will never be executed)";
}
}
// When Exception has been thrown by try block
catch(Exception $e){
echo "
Exception Caught", $e->getMessage();
}
//this block code will always executed.
finally{
echo "
Final block will be always executed";
}
}
// Exception will not be rised here
printdata(0);
// Exception will be rised
printdata(6);
?>輸出
Final block will be always executed Exception CaughtNumber is six. Final block will be always executed
備註
要處理異常,程式程式碼必須在 try 塊內。每個 try 必須至少有一個相應的 catch 塊。可以使用多個 catch 塊來捕獲不同類的異常。
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