Student number 20175212 《Java Programming 》 The first 3 Weekly learning summary

Summary of the learning content of the textbook

One 、 Java—— Object oriented language

The core content is the object , It's all about objects . Here are three important properties :

  1. encapsulation : Encapsulate data and operations on data .
  2. Inherit : Subclasses can inherit the properties and behaviors of their parents .
  3. polymorphic : One makes multiple operations have the same name , But these operations accept different types of messages ; The other is that consent operations may have different behaviors when called by different types of objects .

Two 、 Construction method and object creation

1.“ Construction method ” Is a special method in a class ( You can customize or use the default ), To create objects using , The constructor name must be the same as the class name it is in . The constructor has no type , Such as :

Point(){
x = 1;
y = 1;
}

2. When you create an object , Use new Operator and Construction method of class Assign variables to declared objects . Here is an example 4-2

class Point {
int x,y;
Point(int a,int b) {
x=a;
y=b;
}
} public class Example4_2 {
public static void main(String args[]) {
Point p1,p2; // Declare objects p1 and p2
p1=new Point(10,10); // Assign variables to objects ( Use new And the constructor in the class )
p2=new Point(23,35); // Assign variables to objects ( Use new And the constructor in the class )
}
}

3、 ... and 、 The basic structure of class and program

1. In a Java In the application , Can write a number of source files , Run... In the main class , And the main class compilation needs to use the previous bytecode file , It needs to be in the same directory , Or you'll make a mistake . Here's the picture

2. You can use javac *.java Command to compile all source files in the directory .

Four 、 Instance members and class members

1. Instance variables : Change with different objects of this class .

Class variables ( Add before defining data type static): All objects in this class share this class variable .

2. Instance method and class method : It's about the same as using instance variables and class variables , Generally, it can be used import java.util.*; Introduce call Arrays Class static Method .

Four 、 Method overloading

Multiple methods in a class have the same name , But the parameters of the method are different .

5、 ... and 、 this key word

  1. The construction method is used in this:this Represents the object created by the constructor .
  2. Use... In the instance method this, Represents the current object that is calling the method .

6、 ... and 、 package

  1. Files with packages should be compiled in the parent directory of the package javac tom\jiafei\ Source file , Also run here java tom.jiafei. Main class name The full name of the main class is “” Package name . Main class name

Problems and solutions in textbook learning

  • problem 1: Cannot run an executable file in a subdirectory in the parent directory .
  • problem 1 Solution : Ask for the help of teachers and classmates on blue cloud and check it on the Internet .

Problems and resolution in code debugging

  • problem 1:
  • problem 1 Solution : Learn from students' blogs and online search JDB After debugging the rules

Managed code

Summary of wrong questions in last week's exam

  • The running result of the following program is
public static void main(String args[]) {
char s1[]="ABCDEF\0".toCharArray();
int i=0;
while(s1[i++]!='\0')
System.out.println(s1[i++]);

}

A .ABCDEF

B .BDF

C .ABCDE

D .BCDE

Reasons for wrong questions : The meaning of the code is not understood correctly , Result in running result analysis error

other ( Sentiment 、 Thinking etc. , Optional )

This chapter has a large amount of code , The content is basic, but the key , A lot of effort , Also need to review in time .

Learning progress bar

Lines of code ( newly added / The cumulative ) Amount of blog ( newly added / The cumulative ) Learning time ( newly added / The cumulative ) Important growth
The goal is 5000 That's ok 30 piece 400 Hours
The first week 6/6 1/1 20/20
In the second week of 245/251 1/2 18/38
The third week 633/884 1/3 22/60

Try recording 「 Plan your study time 」 and 「 Actual study time 」, At the end of the period, see if you can improve your planning ability . This job is very important in study , It's also very useful. .

A formula for estimating time consumption

:Y=X+X/N ,Y=X-X/N, More training ,X、Y It's close .

Reference resources : Why is software engineering software estimation so difficult , Software Engineering Estimation method

  • Improve the situation :

( Take a look at it when you have time Modern software engineering Courseware

Software engineer ability self evaluation form
)

Reference material

Student number 20175212 《Java Programming 》 The first 3 Learn more articles about this week

  1. Student number 20175212 《Java Programming 》 Learning summary week nine

    Student number 20175212 <Java Programming > Learning summary week nine Summary of the learning content of the textbook One .MySQL Database management system 1. Download and install on the official website MySQL 2. stay IDEA Enter the test code Connectio ...

  2. Student number 20145303 《Java Programming 》 Study summary of the first week

    Student number 20145303 <Java Programming > Study summary of the first week Summary of the learning content of the textbook *dos Command line : dir: Lists the files and file names in the current directory md: Create directory rd: Delete directory . Empty folder ( The folder is empty ...

  3. Student number 20145322 《Java Programming 》 Study summary of the first week

    Student number 20145322 <Java Programming > Study summary of the first week Summary of the learning content of the textbook Java Born in Sun company , On 1998 year 12 month 4 Promulgated by the J2SE, Major version updates will be launched in a two-year cycle . 2010 year Or ...

  4. 20175227 Zhang Xueying 2018-2019-2 《Java Programming 》 Learning summary week nine

    20175227 Zhang Xueying 2018-2019-2 <Java Programming > Learning summary week nine Summary of the learning content of the textbook Chapter 11 JDBC Database operation MySQL Database management system Download and install MySQL If the download is ...

  5. 201521123061 《Java Programming 》 Learning summary week nine

    201521123061 <Java Programming > Learning summary week nine 1. This week's learning summary 2. Written work This time PTA The problem set is abnormal 1. Common exceptions subject 5-1 1.1 Screenshot of your submission ( The student number appears ) 1 ...

  6. 201521123038 《Java Programming 》 Learning summary week nine

    201521123038 <Java Programming > Learning summary week nine 1. This week's learning summary 1.1 In the way you like ( Mind mapping or something ) Summarize the content related to exception . 2. Written work This time PTA The problem set is abnormal ...

  7. 201521123045 &lt;java Programming &gt; The first 11 Weekly learning summary

    201521123045 <java Programming > The first 11 Weekly learning summary 1. This week's learning summary 2. Written work 2. Written work Q1.1. Exclusive access and synchronous access to complete the question set 4-4( Exclusive access ) And 4-5( Synchronous access ...

  8. 20175313 Zhang Lixian 《Java Programming 》 Learning summary week nine

    Catalog Student number 20175313 <Java Programming > Learning summary week nine One . Summary of the learning content of the textbook Two . Problems and solutions in textbook learning 3、 ... and . Managed code Four . Experience 5、 ... and . Learning progress bar 6、 ... and . Reference material Student number 20 ...

  9. 2018-2019-3《Java Programming 》 Second week learning summary

    Student number 20175329 2018-2019-3<Java Programming > Second week learning summary Summary of the learning content of the textbook       The second and third chapters are related to what we have learned C There are many similarities in languages , Here I would like to mainly discuss the effect of what I have learned ...

  10. # 20175329 2018-2019-2 《Java Programming 》 Second week learning summary

    Student number 2018-2019-3<Java Programming > Second week learning summary Summary of the learning content of the textbook       The second and third chapters are related to what we have learned C There are many similarities in languages , Here I would like to mainly discuss the effect of what I have learned JAVA And ...

Random recommendation

  1. Attach database failed ,sql2008, The power down database log is corrupted

    Attach database failed , Tips : Can't access the database 'DBNAME' ( database ID by 7) Page of (1:210288) Redo business on the Internet ID (0:0) Logging or redoing the database 'DBNAME' Operations recorded in the log of ...

  2. viewPager Dynamic loading listview data

    I don't say much nonsense , First on the renderings .( The code is attached ) The code was modified from a God , I made a lot of changes , Before that, you can only slide to the right , Now you can slide left and right infinitely , As long as the data is not loaded, it can slide all the time . The process is not complicated , The main parts of the code have comments . The attachment dem ...

  3. auto_ptr Design motivation

    auto_ptr Design motivation C++ The standard library provides auto_ptr It's an intelligent pointer (smart pointer), Help programmers prevent “ A resource leak occurs when an exception is thrown ”. Functions often operate in the following pattern : 1. obtain ...

  4. .cs File with the aspx.cs What's the difference between files ??? What is their role ???ASPX What is the function of documents ?

    Generally in vs A new page will produce two kinds of files : One is a suffix called .cs Of , One is .aspx. To put it simply ,.cs Files are usually implemented in it , and .aspx Is to achieve the interface effect . difference :.cs The file says .net Of ...

  5. mysql The concurrent processing mechanism of _ Part 1

              Come back and blog , The youth front end time is django Lost in my heart           If reprinted , Please indicate the source of the blog : www.cnblogs.com/xinysu/   , Copyright Blog Garden Su's radish the ...

  6. Electron Practical desktop calculator application

    Preface Electron It's a framework for building cross platform desktop applications , Only use JavaScript.HTML as well as CSS, You can quickly and easily build a native application . It's a huge benefit for developers who want to be involved in other areas . ...

  7. Dynamics CRM ADFS And IFD Extend system logout time after deployment

    Dynamics CRM  Deploy IFD after , After a period of time, the login status will be invalid , The system will prompt you to log in again , It can be avoided by extending the failure time stay  powershell The following instructions are executed in Set-ADFSRelyingPartyT ...

  8. Front end artifact - God level code editing software Sublime Text download 、 Use the tutorial 、 Plug in recommendations 、 Full set of shortcuts

    Sublime Text It's a code editor , It's also HTML And prose advanced text editor .Sublime Text By programmers Jon Skinner On 2008 year 1 Developed in June , It was originally designed as a rich extension ...

  9. ABP What is ABP(ASP.NET Boilerplate)

    1. Introduce ABP It is an open source and well documented application framework . It's not just a framework , Consider its best practices ,ABP It also provides domain driven design (DDD) A powerful price model for . ABP Support the latest ASP.NET Core and EF C ...

  10. SNF Rapid development platform 2019-APP The practical application effect of mobile terminal

    I don't say much nonsense , Go straight to the renderings : This is the basic program of our mobile framework + Component library + Standard business procedures , Of course, we also need to cooperate with our code generator, which is even more powerful .https://www.cnblogs.com/spring_wang/p ...