看到书上有这么一段话:
通常,JSP 引擎检查 JSP 文件的 servlet 是否已存在,JSP 的修改日期是否比 servlet 的过时。如果 JSP 的修改日期比其生成的 servlet 的修改日期过时,那么 JSP 容器假设 JSP 修改日期没有改变,且生成的 servlet 的修改日期仍然与 JSP 的内容相匹配。与其他脚本语言(比如 PHP)相比,这个过程更有效率,因此更加快速。
请问php是怎样的一个过程呢?
回复内容:
看到书上有这么一段话:
通常,JSP 引擎检查 JSP 文件的 servlet 是否已存在,JSP 的修改日期是否比 servlet 的过时。如果 JSP 的修改日期比其生成的 servlet 的修改日期过时,那么 JSP 容器假设 JSP 修改日期没有改变,且生成的 servlet 的修改日期仍然与 JSP 的内容相匹配。与其他脚本语言(比如 PHP)相比,这个过程更有效率,因此更加快速。
请问php是怎样的一个过程呢?
PHP并不是这样一个过程,因为PHP是每次请求都要编译的,所以就不再需要判断代码是否更新了。
另外PHP的编译与JSP的编译也存在很大差别,PHP因为每次都会编译,为了加快编译速度,去掉了代码优化等过程,其编译速度要比JSP来得快,但是也不能一概而论,比较JSP是一次编译长期使用,而PHP不是。如果进行比较,只能说各有特色各有针对。

PHP type prompts to improve code quality and readability. 1) Scalar type tips: Since PHP7.0, basic data types are allowed to be specified in function parameters, such as int, float, etc. 2) Return type prompt: Ensure the consistency of the function return value type. 3) Union type prompt: Since PHP8.0, multiple types are allowed to be specified in function parameters or return values. 4) Nullable type prompt: Allows to include null values and handle functions that may return null values.

In PHP, use the clone keyword to create a copy of the object and customize the cloning behavior through the \_\_clone magic method. 1. Use the clone keyword to make a shallow copy, cloning the object's properties but not the object's properties. 2. The \_\_clone method can deeply copy nested objects to avoid shallow copying problems. 3. Pay attention to avoid circular references and performance problems in cloning, and optimize cloning operations to improve efficiency.

PHP is suitable for web development and content management systems, and Python is suitable for data science, machine learning and automation scripts. 1.PHP performs well in building fast and scalable websites and applications and is commonly used in CMS such as WordPress. 2. Python has performed outstandingly in the fields of data science and machine learning, with rich libraries such as NumPy and TensorFlow.

Key players in HTTP cache headers include Cache-Control, ETag, and Last-Modified. 1.Cache-Control is used to control caching policies. Example: Cache-Control:max-age=3600,public. 2. ETag verifies resource changes through unique identifiers, example: ETag: "686897696a7c876b7e". 3.Last-Modified indicates the resource's last modification time, example: Last-Modified:Wed,21Oct201507:28:00GMT.

In PHP, password_hash and password_verify functions should be used to implement secure password hashing, and MD5 or SHA1 should not be used. 1) password_hash generates a hash containing salt values to enhance security. 2) Password_verify verify password and ensure security by comparing hash values. 3) MD5 and SHA1 are vulnerable and lack salt values, and are not suitable for modern password security.

PHP is a server-side scripting language used for dynamic web development and server-side applications. 1.PHP is an interpreted language that does not require compilation and is suitable for rapid development. 2. PHP code is embedded in HTML, making it easy to develop web pages. 3. PHP processes server-side logic, generates HTML output, and supports user interaction and data processing. 4. PHP can interact with the database, process form submission, and execute server-side tasks.

PHP has shaped the network over the past few decades and will continue to play an important role in web development. 1) PHP originated in 1994 and has become the first choice for developers due to its ease of use and seamless integration with MySQL. 2) Its core functions include generating dynamic content and integrating with the database, allowing the website to be updated in real time and displayed in personalized manner. 3) The wide application and ecosystem of PHP have driven its long-term impact, but it also faces version updates and security challenges. 4) Performance improvements in recent years, such as the release of PHP7, enable it to compete with modern languages. 5) In the future, PHP needs to deal with new challenges such as containerization and microservices, but its flexibility and active community make it adaptable.

The core benefits of PHP include ease of learning, strong web development support, rich libraries and frameworks, high performance and scalability, cross-platform compatibility, and cost-effectiveness. 1) Easy to learn and use, suitable for beginners; 2) Good integration with web servers and supports multiple databases; 3) Have powerful frameworks such as Laravel; 4) High performance can be achieved through optimization; 5) Support multiple operating systems; 6) Open source to reduce development costs.


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