takeaway

This is the fourth article in the recommended Learning Java series. The first three articles have covered the content of JavaASE, and now it’s time to truly enter the horizon of Java backend development. To understand the basic learning route, you may have such a question: the front content should be learned at all? Does Java development need to be front-end? The following is to analyze each one.

Java regular expressions

Before you begin, take you to learn first in Java regular expressions, the content can either put Java based part learning, can also to learn now, in contrast, is more suitable to be learn now, because the learning of the backend development, need to all validation data, including regular match is little not, here is to learn.

What is a regular expression

Use a special symbol concatenation to validate certain rules on a particular string, and the concatenation formed by this special symbol is a regular expression.

Pros and cons of regular expressions: easy to write, poor reading

Regular expression syntax rules

  • [ABC] stands for A, B, or C (simple class)
  • [A-Za-Z] means A to Z or A to Z
  • \d denotes number: [0-9]
  • \D stands for non-number
  • \s represents white space characters (such as Spaces, \t tabs, \n newlines, etc.)
  • \S represents a non-white space character (anything but a white space character)
  • \ W denote word character: [a-za-z_0-9]
  • \W represents a non-word character
  • X{n} represents X, which occurs exactly n times
  • X{n} means X, at least n times
  • X{n,m} denotes X, at least n times, but not more than m times

In a regular expression, the ^ represents the regular actual tag and the $represents the closing tag (which can be left out).

Front-end things that Java development should know

  • Simple HTML
  • Simple CSS
  • To master the Servlet

For HTML only need to be able to understand simple code and write a simple static page can be; For CSS, you only need to know the common properties and selectors and how to introduce them into HTML pages. For servlets, you need to focus on the former two, understand the execution process and response process of the request, as well as the application of forwarding and redirection.

As for JavaScript, jQuery, Ajax, JSP, and XML, which we often hear about, you don’t need to know. They all belong to the front-end category. Of course, if you have a basic knowledge of these languages, it is even better.

The development tools

The front-end development Xiaobian chose is: HBuilder X

Download address: https://www.dcloud.io/hbuilderx.html

There are a lot of tools. Xiaobian chooses this one mainly because he plans to launch uni-app in the future, so it will be in place all at once. You can choose the tool you are comfortable with, and it is not necessary to unify this tool.

I have mentioned the content of the front end to learn, but I will not go into details here. I have drawn a very detailed knowledge map for you, so you can follow the following rules:

Java development Xiaobian choice is: IntelliJ IDEA

The introduction of the IDEA tool is omitted here. Download and configure the environment can be seen in the first article of the recommendation to learn Java.

The following is about the content of Servlet, this content learning to be carried out in Java development, will be combined with the content of the front end, so the front Xiaobian will be included in the category of the front end to learn.

Java backend environment

All projects here refer to Java Web projects, which are different from the Java projects we learned earlier. This section mainly studies the following points:

  • Tomcat environment configuration
  • Create a Java Web project
  • Deploy the Java Web project
  • Java Web project directory structure description
  • Run the Java Web project

Tomcat environment configuration

Official website to download address: http://tomcat.apache.org/

Relative to the configuration of the JDK when we learn JavaSE is simple, refer to the map can be done, recommend everyone to download the unzip and use version, download a point: be sure to download and your computer the same number of digits.

Create a Java Web project

In fact, it is very simple. Of course, this is also related to the version of IDEA, which is made up of IntelliJ IDEA 2021.1.1 version.

Deploy the Java Web project

This one is a little bit more difficult, but it’s not too hard. You can get the process done with a simple hands-on program. Practice makes perfect.

It should be noted that, for example, in the practice of developing the login registration function of XXX system, the server will be repeatedly deployed and restarted, so a trip down you must be familiar with it.

conclusion

This section is to really enter the Java backend development to do the groundwork, the next section will sort out the specific learning route and key points, start the journey of Java!

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