1. Java overview, java Overview

1. Java overview, java Overview

1. java Overview

1. Preface 1.1 learning methods

1. Learning Methods 2. Learning to solve problems independently 3. Active learning rather than passive acceptance 4. ability is your own.

1.2 recommendation blog

Modern programmers should develop the habit of writing and reading blogs.

1. [blog garden] (http://www.cnblogs.com/) 2. [CSDN] (http://www.csdn.net /)

1.3 blog editing artifacts

1. [MacDwon download installation] (http://macdown.uranusjr.com/) 2. [MacDown usage tutorial] (http://www.jianshu.com/p/1e402922ee32)

2. Content: Java overview 2.1 Java language development history 2.1.1 computer language development history

Answer a few questions after reading the computer language:

1. what is computer language 2. what are the categories of computer languages from low-level and advanced levels? 3. what are the types of advanced computer languages and their respective advantages and disadvantages? 4. which advanced computer languages have you used or heard?

2.1.2 Java Language Development History

After reading the java language, I will answer a few questions:

1. What is JDK? 2. What is JRE? 3. What three platforms does java have? 4. What are java development tools? 5. What systems can java develop on? 6. What are the features of Java?

2.2 Java operating mechanism

Answer several questions after reading JVM:

1. What is JVM 2. How is a Java program running?

2.3 build a Java Development Environment 2.3.1 install JDK

JDK

Note:

1. Install x86 on a 32-bit operating system, and install x642. during JDK installation, do not change the installation path. Use the default path for installation. continue to the next step.

2.3.2 environment variable configuration

1. add variable name: JAVA_HOME variable value: JDK installation path (for example, C: \ Program Files \ Java \ jdk1.8.0 _ 31) 2. modify the variable name: PATH variable value: % JAVA_HOME % \ bin; (win7 is placed at the beginning, be sure not to overwrite the original content, the last; number cannot be less; win10 is created in path, it is best to put it at the beginning) 3. add variable name: CLASSPATH variable value :.; % JAVA_HOME % \ lib \ dt. jar; % JAVA_HOME % \ lib \ tools. jar4. Check Configuration: CMD command line Input: java-version CMD command line Input: javac if the configuration fails, you can run the cmd command echo to check the JAVA_HOME environment: echo % JAVA_HOME % to check the CLASSPATH environment: echo % CLASSPATH % check Path Environment: echo % Path % Note: if it still fails, you can log out of the user or restart the computer.

2.3.3 install and configure Eclipse

Problem:

Eclipse

Eclipse Configuration:

1. the workspace is used to save the program project and related settings. Check "use this value as the default value and do not ask. 2. when the workspace is restarted, the following message is displayed: windows> Preference> General> startup and shutdown. Check Refresh workspace on startup3. to modify the encoding format: menu windows-> preference-> General-> under workspace select the encoding format for UTF-8: 4. modify Automatic Content assist: menu windows-> preference-> Java-> Editor-> Content Assistant, modification time delay: 100 (MS) automatic activation Content: abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ. _

Common Eclipse shortcut keys:

1. alt +? Or alt +/: Automatically complete the code or prompt the code. 2. Control/command + o: Quick outline View. 3. Control/command + shift + r: Open the resource list. 4. Control/command + shift + f: format the code. 5. Control/command + e: Quick conversion editor. 6. Control/command + page down ([) or Control/Command + page up (]): Quick Switch between tabs. 7. shift + enter and ctrl + shift + enter: Create a blank space under or above the current row. 8. Alt + arrow keys: the upper and lower rows exchange content or move the content of the current row up or down. 9. Control/Command + Alt + up/down keys: copy one or more highlighted rows. 10. Control/Command + m: The current editing page window is maximized. 11. Control/Command +/: automatically comments the current row or multiple selected rows. 12. Control/Command + d: Delete the current row. 13. Control/Command + shift + o: automatically introduces and deletes useless packages.

You can use Help-> Show Active Keybindings to view

2.3.4 Notepad ++

Notepad ++ is a powerful free text editor

Notepad ++

2.4 compile and run Java programs

Write the first Java program:

public class Helloworld{    public void main (String[] args){        System.out.println("Hello world");    }}

2.5 basic structure of Java program 4. Practices and exercises