1.
Front desk: visual and basic operations presented to users.
Background: When users browse the web, the background data that we can't see runs. The back-end includes front-end and back-end.
Front end: Corresponding to the webpage languages we wrote, such as html, css, javascript, act on the front-end webpage.
Back-end: business logic code corresponding to jsp, javaBean, dao layer, action layer and service layer. (Including database)
Why is jsp the backend? Mainly the operating principle of jsp is running on the tomcat server.
2.
(1) Javaweb is a direction in java development. Java has Android, web, embedded and so on. Javaweb refers to the web direction. Javaweb is divided into two parts, one is the server side called the back end, and the other is called the front end, which is the web front end. The front end is the part that users can see, such as Taobao, QQ space, and what you can see on web pages is done by the web front end. What the backend does is to process the front-end display business logic functions.
(2) Java web includes jsp, servelt and some frameworks such as spring, structs and knowledge of interacting with databases. Of course, it also involves front-end technologies such as html and css, but it focuses more on back-end development. The web front end is mainly html, css, javascript and other technologies.
Jaweb is a direction of javaee. Javaweb consists of three major aspects: front-end, Java code, and database. The front-end is just one of them.
(3) The interface seen on our machine, the installed program, what is shown to the user, and the operation is the front end; what you can’t see is to help you save the online game data, save the application data, and process the data is the back End (server). For example: The Zhihu we are using is the front-end, and the one that saves this problem and pushes this problem to you is the back-end.
2. Different definitions
Generally speaking, we divide the website into front-end and back-end. The front end is mainly responsible for the display of the page, and the back end is the realization of business logic.
1. Web front-end:
As the name suggests, it is to do the front-end of the Web. The front-end mentioned here generally refers to the front-end of the Web, that is, what the user can see and touch in the Web application. Including the structure of the Web page, the visual appearance of the Web and the realization of the interaction at the Web level.
2. Web back-end: the
back-end is more to interact with the database to process the corresponding business logic. What needs to be considered is how to implement functions, data access, platform stability and performance, etc.
3. Different technologies to master
1. Web front-end:
proficient in JS, proficient in the application of JQuery, understand CSS, proficient in the use of these knowledge, development of interactive effects.
(1) Proficient in HTML, able to write HTML structure with reasonable semantics, clear structure, and easy to maintain;
(2) Proficient in CSS, able to restore visual design, and compatible with mainstream browsers recognized by the industry;
(3) Familiar with JavaScript and understand the basic content of ECMAScript , Master 1-2 kinds of js frameworks, such as JQuery;
(4) Have a clear understanding of common browser compatibility issues and have reliable solutions;
(5) Have certain requirements on performance, and understand yahoo’s performance optimization suggestions , And can be effectively implemented in the project.
2. Web back-end:
back-end developers: can write Java code, can write SQL statements, can do simple database design, know Spring and iBatis, understand some design patterns, etc.
(1) Proficient in jsp, servlet, javabean, JMS, EJB, Jdbc, Flex development, or very familiar with related tools, class libraries and frameworks, such as Velocity, Spring, Hibernate, iBatis, OSGI, etc., have some knowledge of Web development modes Deeper understanding;
(2) Practicing the use of commonly used database systems such as oracle, sqlserver, mysql, and having strong design capabilities for databases;
(3) Familiar with maven project configuration management tools, familiar with application servers such as tomcat, jboss, and Relevant experience in load tuning under high concurrency processing is preferred;
(4) Proficient in object-oriented analysis and design techniques, including design patterns, UML modeling, etc.;
(5) Familiar with network programming, with design and development of external API Interface experience and ability, as well as cross-platform API specification design and API efficient call design capabilities.
4. How are web backends and frontends connected?
1. Web server (apache, tomcat, etc.), network protocol (http, socket, etc.), browser (chrome, FF, IE, etc.). The browser initiates a connection request, establishes a connection with the server through the network protocol, the server maintains the connection, and obtains the data that the browser wants, the server returns the content to the browser through the connection, and the browser presents the data.
2. The connection protocol is generally http, but also websocket. The server exists in the form of service, just like a takeaway shop. You make a phone call, and the food is delivered to the door.
3. The web server needs to use the network connection to access the database, and the port is only the entrance of the open service, just like a takeaway phone.
5. The difference between JavaWeb and web front-end?
1. The web front-end is mainly used to make static pages for the website, which means that the pages you see on the websites you usually browse are basically from the web front-end, but the website layout can be artwork.
The technologies that the web front end needs to master are: DIV+CSS, j, jQuery, and the higher level is to use some frameworks to go to the website pages. There are many such frameworks. Such as Bootstrap, UIkit, Kube and so on.
2, javaweb generally involves the front end. The web front-end development may only involve java.
Front-end development generally only involves js, html, css, some may use flash, photoshop. The framework is jquery, ext, jodo, etc.
In the case of web front-end, its back-end may be java, .net or php, etc., but javaweb can determine that the back-end is java, and the web front-end is actually the same.
The difference between the front-end and Javaweb is more that one is mainly responsible for the design and effects of the front-end, while Javaweb is more focused on the back-end content.
3. When you first started to engage in web development, you must first choose the right learning direction, depending on whether you want to engage in the front-end part or the back-end program part. Of course, in the later stages of the work, it will not be so detailed. From the front end to the later stage, you will also understand some back-end technologies, and vice versa, the back-end is also true.
6. What skills are needed to learn Web front-end development?
1. Learn html. This is the simplest and the most basic. To be proficient in div, form table, ul li, p, span, font these tags, these are the most commonly used, especially div and table, div is used for layout, table also Can be used for layout, but not flexible, the basic table is used to deal with data.
2. Learn css. The css mentioned here does not include css3. Generally, we see that among the requirements of web front-end development engineers, one will use css+html or css+div for interface layout, so css is used to assist html to layout and display, we Call it "css style", why do you say css+div? Because I said above that div is mainly used for layout of html, so div is the core thing! Then css must be used with div .css must be proficient in float, position, width, height, as well as the maximum and minimum, will use 100%, overflow, margin, padding, etc., these are all styles related to the layout, and you must master one point.
3. Learn js. Maybe the first two people think that they are still passing, and they are dumbfounded when they see js. Actually, the introduction of js is very simple. You don't need to know a lot of things. As long as you can get the web page dom or style according to a certain id or name, Or value, and then assign a value to the element tag of a certain id or name, or append data, and chase html.This is an operation related to the data, and then the data is logically judged, and the effect is nothing more than jumping, popping, and hiding What? Combining all of these with others is for practical purposes. The code is not difficult at all. After knowing these basic js, the other ones will be directly Baidu. Then see more, use more, nothing is a problem.
4. Learn jquery. Jquery is a js plug-in equivalent to encapsulating a set of js. The purpose is to make it more convenient to operate, write less code, and get started with jquery is also very simple. Those who need to learn are the same as js, but replaced with jq Code. Baidu is enough for everything else.
5. It is best to use background language, such as java, php, why? Because the data of the foreground interface comes from the background, if you can click the background code, you will know how to interact with the background data is the best, so as to save time , You can also make the front-end code more standardized. Otherwise, because your writing and the data from the back-end cannot be combined, then the front-end code has to be rewritten, which is even more troublesome.
6. Learning css3+html5, maybe this is a bit difficult for newcomers to take over, requiring strong code knowledge and experience, but if you are going to specialize in front-end, then it is best to learn it, so that it will be useful for future work There is greater help.
7. What skills do I need to master when engaging in Java back-end development?
For students who are new to Java and are interested in back-end development, they need to focus on the following parts:
1. Basics: such as computer systems, algorithms, compilation principles, etc.
2. Web development: mainly related to Web development, including Knowledge of HTML/CSS/js (front-end page), Servlet/JSP (J2EE) and MySQL (database). Their order of learning should be from front to back, so the first to learn should be HTML/CSS/JS (front-end page). There are also some front-end frameworks such as easyui, js, jquery and other technologies.
3. J2EE: What you need to learn is the Servlet/JSP (J2EE) part, which is the part that must be very proficient in Java back-end development, so this part is the most energy-intensive part of the three parts. Regarding the selection of some videos of Servlet/Jsp, the industry recognizes the video of Soldier Ma. 4. Database: You need to learn to use the database. MySQL is a good entry choice, and the mainstream relational database in the Java field is mysql. This part is generally encountered when you learn Servlet/Jsp, and the JDBC part is the database-related part. You must not only learn to use JDBC to operate the database, but also learn to use database client tools, such as Navicat, sqlyog, choose one of the two.
5. Development framework: SSM framework is currently more mainstream, namely spring, springmvc, mybatis. You need to learn how to build these three frameworks, and use them to make a simple addition, deletion, modification, and checking Web project. You don't need to understand what those configurations mean and why you want to do this. These are for you to understand later. But you must be able to quickly use these three to build a web framework. In the process of building SSM, you may often come into contact with a tool called maven. This tool is also a tool that you almost must use in your future work, so you can also learn about maven in the process of building SSM. At your current stage, you only need to learn about the basic usage of maven on the Internet. Some high-end usages will be gradually exposed as your work experience increases.
6. You need to look at the source code of some classes in the JDK, including the source code of the framework you are using. The premise that these source codes can be understood is that you must have a good understanding of design patterns. Otherwise, when you look at the source code, you will always have questions like this. Why is this code written like this? Why do you want to define this interface, it looks like a lot? It can also be seen that these learning processes are interlocking. If you pull down at any stage, then you really can’t keep up, or it’s a slow step. All in all, at this stage, what you need to do is to have a deep understanding of the underlying Java and Java class libraries (for example, the concurrency book is the content of the Java concurrency package java.concurrent), that is, the related content of JVM and JDK. And you need to know more about the framework you are using. It is recommended to look at the source code or look at the official documentation.