How can PHP check if a piece of code is abnormal?

In PHP, try-catch blocks can be used to catch and handle exceptions.

Here is an example code:

try {
    // 这里是一串可能会出现异常的代码
    // ...
} catch (Exception $e) {
    // 捕获到异常后的处理代码
    echo '异常消息：' . $e->getMessage();
}

Within the try block, you can place a series of code that may potentially raise an exception. If an exception occurs during execution, it will be thrown and caught by the catch block.

In the catch block, you can handle the caught exception. In the example above, the getMessage() method is used to retrieve the exception message and output it.

Different catch blocks can be added according to specific needs to catch different types of exceptions and to handle them differently.