Introduction to java learning process

First of all, the learning method that I personally recommend is: first learn the front part of Java, that is, HTML, css, js, because after learning Java, you will definitely develop in the direction of Java ee. After finishing the front-end, it is easier to understand many things in the back-end than before! (Recommended: java video tutorial)

Among them, J2SE is the key. If you learn the java se part well and have a solid foundation, it will be easier to learn more later!

Additional explanation: I think the more appropriate way to learn Java is to go through all the knowledge points first, and then connect all the knowledge points together, and add them while developing, just like writing an article, first Write the frame and then polish and fill it. Because in the early stage of learning, you don’t know where to use it, what it is used for, and there is no purpose of learning, so many concepts are difficult to understand and easy to forget after a long time.

But if you start learning directly from practice, many knowledge points will be connected in series, and you will be deeply impressed. Of course, the prerequisite is that you have already started and can write some simple programs. I personally follow the After learning this method, I feel it is very effective.

Note: The content introduced in this article is too detailed. Here I will add some basic learning routes, which are relatively simple but feasible:

1. Basic grammar. That is to say, we often say that various programming languages ​​have parts, such as data types, arrays, for loops, do-while, switch... etc., which are the basis for learning any programming language and are very important.

2. Object-oriented: ① Classes and objects; ② Java’s three major features (encapsulation, inheritance, polymorphism);

3. Tool classes: ① Exceptions and exception handling; ② Collections Framework (mainly List and Map);

4. Commonly used streams: ①Input stream; ②Output stream; ③Buffer stream;

5. Network and threads: ①Socket; ②Multi-threading (Thread, Runnable);

6. Data operations: ①Mysql, Oracle; ②JDBC;

7. Web basics: ①Html/css; ②Javascript; ③JQuery;

8. Frame.

As long as you learn the first 7 items above, it is basically not a big problem to develop common applications from the front desk to the back desk. Of course, it will be best after you learn the framework, but the key is to learn the basics well. To be honest, it is still difficult to fully grasp the knowledge points listed in the table below, so you still have to study calmly and calmly. Don't just look at the progress of learning, but also the effect of learning.

The first stage	Technical Name	Technical Content
##J2SE (javaBasic part )	Prelude to java development	Basic principles of computers, a brief history of the development of the Java language and the establishment of a development environment, experience the development of Java programs, and environment variables Settings, program execution process, introduction to related decompilation tools, installation and use of the Java development tool Eclipse, and javadoc instructions.
	Java basic syntax	Java syntax format, constants and variables, variable scope, methods and methods Overloading, operators, program flow control, arrays and classes that operate arrays, array loop traversal and common search and sorting algorithm principles for arrays, and finally use Java programs to implement functions.
	Object-Oriented Programming	Understand the nature of objects, as well as object-oriented, the relationship between classes and objects, how to use object-oriented thinking to analyze and solve problems in life, and write them using Java programs. How to design a class, the basic principles of designing a class, the instantiation process of a class, class elements: constructor, this keyword, method and method parameter passing process, static keyword, inner class, Java's garbage object recycling mechanism. The three major characteristics of objects: encapsulation, inheritance and polymorphism. The instantiation process of subclass objects, method rewriting and overloading, final keyword, abstract classes, interfaces, advantages and disadvantages of inheritance. Polymorphism of objects: conversion between subclasses and parent classes, references from parent classes to subclasses, application of abstract classes and interfaces in polymorphism, and the advantages of polymorphism. Commonly used design patterns include simple interest, template and other patterns. What is an exception? Exception catching and throwing. The principle of exception catching. The use of finally, the application of package and the import keyword.
	Multi-threaded application	The concept of multi-threading, how to create multi-threads (Thread, Runnable) in the program , Thread safety issues, thread synchronization, communication between threads, and analysis of deadlock problems.
	detailed explanation of javaAPI	Introduction to JavaAPI, String and StringBuffer, various basic data type packaging classes, System and Runtime class, Date and DateFomat classes, etc. Commonly used collection classes are as follows: Java Collections Framework: Collection, Set, List, ArrayList, Vector, LinkedList, Hashset, TreeSet, Map, HashMap, TreeMap, Iterator, Enumeration and other common collection class APIs.
	IO technology	What is IO, File and related classes, byte streams InputStream and OutputStream, character stream Reader and Writer, as well as the corresponding buffer stream and pipe stream, byte and character conversion stream, packaging stream, and the use of common packaging classes, analyze the IO performance of Java.
	Network programming	Java network programming, network communication underlying protocol TCP/UDP/IP, Socket programming. Introduction to commonly used application layer protocols for network communication: HTTP, FTP, etc., as well as the working principle of WEB servers.
	java advanced features	Recursive programs, Java’s advanced features: reflection, proxy and generics, enumeration , Java regular expression API detailed explanation and its application.

second stage	Technical Name	Technical Content
Database Technology	Oracle Basic Management	Oracle background introduction, database installation, database user name and password, client login database service SQLPLUS, database basics Overview.
	SQL statements	Creation of database, creation, modification, deletion, query, index creation of tables, The establishment of master-slave tables, data control authorization and recycling, transaction control, detailed explanation of query statements and operators, and the use of functions in SQL.
	Multiple table joins and subqueries	Equal and non-equivalent joins, outer joins, self-joins; cross Joins, natural joins, using clause joins, complete outer joins and left and right outer joins, subquery usage and precautions.
	Triggers and stored procedures	The usage scenarios of triggers and stored procedures are explained in detail through examples.
	Database design optimization	The connection order in the WHERE clause, select the most efficient table name order, Avoid using ‘ * ‘ in the SELECT clause to calculate the number of records, etc.
	Data backup and transplantation	Transplantation skills, backup plans; import and export, etc.

You can advance the knowledge of the fourth stage, especially for those students who have just started to contact object-oriented programming. I just started learning Java se, and I felt that it was not easy to get started. Learning the web part first is helpful for understanding object-oriented concepts. In addition, the web part is relatively simple and intuitive. You can see the effect immediately after writing, which helps to increase everyone's enthusiasm for learning.

The third phase	Technical Name	Technical Content
##jdbcTechnology ​ ​ ​ ​	JDBC Basics	The use of different classes such as JDBC Connection, Statement, PreparedStatement, CallableStatement, ResultSet, etc.
	Connection pool technology	Understand the concept of connection pool and master the establishment, management, closure and configuration of connection pool .
	ORM and DAO encapsulation	Object relational mapping idea, jdbc dao encapsulation, realize your own jdbc.

The fourth stage	Technical Name	Technical Content
web basic technology (Project actual combat)	Xml technology	Use jdom and dom4j to parse and generate xml documents, the role and usage of xml .
	html/css	Java masters the format and use of basic html tags, css cascading style sheets for divs Definition to achieve the basic implementation of website layout.
	Javascript	Understand the basic syntax of javascript and the use of related functions, and combine it with html pages to realize process control and Page effect display. What is an exception? Exception catching and throwing. The principle of exception catching. The use of finally, the application of package and the import keyword.
	jsp/servlet	Servlet and SP technology, upload and download, Tomcat server technology, servlet filter and monitoring device.
	jstl and EL	JSTL core tag library, function tag library, formatting tag library, custom tags Technology, use of EL expressions in jsp pages.
	ajax and framework technology	Understand and attribute the use of original ajax, the occasions when ajax is used, use The benefits of ajax, ajax framework jquery rendering page effects and related powerful third-party class libraries, how dwr transmits data with background services, and page logic control, etc.
	JSON Advanced Application	Java uses the method supported by json to encapsulate and parse strings to implement page and Data communication for java background services.
	Fckeditor Editor	FCKEditor online editor technology, configuration, processing image and file upload.
	javaMail technology	Understand domain name resolution and MX records, how email works, and mail transfer protocols: SMTP, POP3, IMAP, email organization structure: RFC822 email format, MIME protocol, email encoding, compound email structure analysis, JavaMail API and its architecture, programming to create email content: simple email content, complex emails containing embedded images, including inline Complex emails with pictures and attachments.
	JfreeChart report	Statistical report; chart processing.
	BBS Project Practice	Use Jquery dwr jsp servlet Fckeditor JfreeChart tomcat jdbc (oracle) to complete the actual combat of the BBS project.
	Practical Value	After studying this course, you will already be a programmer with at least nearly 1 year of development experience. , but you should not be satisfied with the status quo, the following courses will attract you more!

In the framework part, you must understand as much as possible the underlying implementation mechanisms and principles. After all, the framework is greatly affected by the environment. The more popular one at this stage is the ssm framework (spring, Spring MVC, mybatis). The following are the more commonly used ones. Framework: (After being able to use the framework for development at this stage, you need to do more projects and type more code. When you are particularly familiar with various application scenarios and can handle various operations at your fingertips, you can consider looking at the source code and studying it. The underlying implementation mechanism to deepen the understanding of the framework)

The fifth classic stage	Technical Name	Technical Content
Web mainstream framework technology (Project actual combat)	struts x.x	Struts framework working principle and architecture analysis, struts-default.xml and default.properties files Function, struts. Multiple configuration files are introduced in Xml. OGNL expressions, Strutsx UI and non-UI tags, input validation, using wildcards to define actions, dynamic method calls, multiple file uploads, custom type converters, injecting values ​​into Action properties, custom interceptors, exception handling, usage A case of CRUD operation implemented by strutsx.
	hibernatex.x	Hibernate application development foundation; ORM basic theory; relational mapping technology; Performance tuning technology; Performance optimization, first-level cache, second-level cache, query cache, transactions and concurrency, pessimistic locking, optimistic locking.
	springxx.x	Spring IoC technology; Spring AOP technology; Spring statement transaction management; Spring common function description, The new features of springx.0, Spring integrates the use of struts and hibernate.
	Spring MVC	Spring’s own mvc framework can replace struts and other MVC frameworks
	mybatis	The current mainstream persistence layer framework requires manual configuration of sql statements and can realize dynamic splicing sql
	Log4j and Junit	Logging API; JUnit unit testing technology; Stress testing technology: badboy performs test plan tracking acquisition and JMeter stress testing.
	Online payment technology	Complete the online payment function of Alipay’s payment interface.
	E-commerce network actual combat	Using spring hibernate struts jquery dwr FckEditor tomcat to complete the actual development of e-commerce website.
	Practical Value	The actual value of the project is completely high standards and high requirements to meet the needs of the enterprise. After learning this After digesting all the courses, you are already an out-and-out senior programmer, which has paved the way for your career. What are you waiting for? Sprint towards a high salary!

Sixth Advanced Stage	Technical Name	Technical Content
Web Advanced Advanced (Project actual combat)	openJpa technology	JPA introduction and development environment construction, single table entity mapping, one-to-many/many-to-one, One-to-one, many-to-many association, entity inheritance, composite primary key, JPQL statement, EntityManager API, transaction management, learn about the new features and applications of jpa2.0.
	lucene search engine	Understand the principles of full-text search, full-text search engine, what is OSEM, OSEM framework Compass, Based on using Lucene and using Compass to implement full-text incremental index creation and search, explore Lucene 3.0 and API.
	E-commerce network reconstruction	This project uses the technology of the previous version of the e-commerce website of Lucene compass openJpa Refactor.
	Practical value	The actual value of this project is unprecedented and has exceeded the actual requirements of the enterprise , you are already a sought-after talent in the company. Once you enter the company, you will be invincible and easily become the company's technical backbone and elite. Technology has changed your life!
	Excel/PDF document processing technology	java uses poi and itext to parse excel and pdf documents respectively. and generate. This technique is often used in reporting in enterprise-level systems.
	OA workflow technology JBPM	What is workflow, introduction to JBPM, main usage of JBPM, various types Usage of nodes, various task assignment methods, overall architectural principles of JBPM, workflow definition model analysis, runtime workflow instance model analysis, database table model analysis, process definition management, process instance monitoring, and encapsulation of JBPM related interfaces , build your own workflow application platform, etc.
	WebService technology	WebService technology principle, WebService technology application, Soap service creation and management, WSDL description Document specifications, operating principles of UDDI registration center; use Axis and Xfire to create WEB services, write Webservice clients, use TCPMonitor to monitor SOAP protocols, and integrate heterogeneous platforms.
	Linux technology	Linux system installation, uninstallation, core ideas of linux use, user management under linux, File management, system management, program installation, use, and uninstallation. Basic applications as a server under Linux: installation of web server, j2ee server, ftp server and project deployment.
	CRM project practice	This project can help you understand and become familiar with the basic process of customer relationship management and the realization of functions. It is implemented using the mainstream framework learned in the above stages, and also adds JBPM technology.
	Practical Value	After learning this system, you will easily enter the development of large-scale enterprise-level projects and feel more comfortable. The complete knowledge system and the most cutting-edge development technology will bring you a different spiritual perspective and the joy of high material salary rewards, taking you to a new turning point and starting point in life!

##Seventh Architecture Stage	Technical Name	Technical Content
Large-scale high-concurrency website optimization plan (Project actual combat)	Detailed explanation of how to build a high-performance website	What kind of website requires high performance and high-performance indicator system to build What work needs to be done for a high-performance website and what details should be paid attention to.
	SSI technology	What is SSI, what are the benefits of using it, and what kind of system uses SSI? Detailed explanation and use of SSI technology and application to projects.
	Technology for generating static pages	What is a static page, why is it needed and the benefits it brings, generate Static page template technology Velocity and Freemark, generate static page access rules, etc.
	Caching technology	Why use caching technology, introduction and use of oscache caching technology, introduction of memcached caching technology And use, comparison of the two caching technologies and how to use them.
	Classic web server	What is a web server, what is a javaweb server, what is their relationship, current technology What are the commonly used web servers in the mainstream, and the applications of web servers apache and nginx.
	nginx architecture practice	What is reverse proxy, load balancing and clustering, and how to implement these in nginx High performance system architecture.
	Practical value	This course has brought you to the threshold of technical managers, supervisors and architects , with a little hard study and practical practice, you will become a technical expert, with a very high salary. At the same time, you will soon become the company's technical middle manager, and your life will take another huge turn!

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