Explore
For Enterprise
Join for Free
Log In

예술 & 인문학
비즈니스
컴퓨터 공학
데이터 과학
정보 기술
건강
수학 및 논리
자기개발
물리 과학 및 공학
사회 과학
언어 학습
학위
수료증

전체 Coursera 둘러보기

검색
포 엔터프라이즈 (For Enterprise)
로그인
무료 회원 가입

Saving Images with New Names

Loading...

Java Programming: Solving Problems with Software

듀크대학교

4.6(2,799개의 평가) | 120K명의 학생이 등록함

Object Oriented Programming in Java 전문 분야에서 4의 강좌 1

Learn to code in Java and improve your programming and problem-solving skills. You will learn to design algorithms as well as develop and debug programs. Using custom open-source classes, you will write programs that access and transform images, websites, and other types of data. At the end of the course you will build a program that determines the popularity of different baby names in the US over time by analyzing comma separated value (CSV) files. After completing this course you will be able to: 1. Edit, compile, and run a Java program; 2. Use conditionals and loops in a Java program; 3. Use Java API documentation in writing programs. 4. Debug a Java program using the scientific method; 5. Write a Java method to solve a specific problem; 6. Develop a set of test cases as part of developing a program; 7. Create a class with multiple methods that work together to solve a problem; and 8. Use divide-and-conquer design techniques for a program that uses multiple methods.

강의 계획서 보기

배우게 될 기술

Algorithms, Problem Solving, String (Computer Science), Java Programming

검토

4.6(2,799개의 평가)

5 stars
2,043 ratings
4 stars
548 ratings
3 stars
114 ratings
2 stars
33 ratings
1 star
61 ratings

DN

Aug 08, 2016

You need a little more experience in coding that just the first course, or try not to leave everything by the end of the week(as I did) to find what you need for the assignments. Great course !

JS

May 19, 2019

Really practical course content with great tutorials. The programming assignments are fun and challenging and deal with real world data and problems which makes the course all the more useful!

수업에서

MiniProject: Baby Names

This module wraps up the course with a mini project that ties together the different practices, skills, and libraries you have gained across the course! Using data on the popularity of different baby names in the United States from the past several decades, you will be able to compare different names’ popularity over time. While the data we have collected for this course is from the United States, we welcome you to share data from other countries in the course discussion forums. Good luck with the mini project!

Batch Grayscale: Converting Many Files2:58

Grayscale Algorithm: Seven Step Approach4:11

Image Iterable in BlueJ: Grayscale5:36

Batch Processing Grayscale3:30

Saving Images with New Names11:14

Batch Grayscale Summary: Converting Many Files1:09

강사:

Owen Astrachan
Professor of the Practice
Robert Duvall
Lecturer
Andrew D. Hilton
Associate Professor of the Practice
Susan H. Rodger
Professor of the Practice

스크립트

Welcome.

Today what we're gonna do is I'm going to show you

how to make copies of images by writing a program to do so.

I've got a file of images on my computer, and

I'd like to actually read some of those images in and make copies of those files.

So we're gonna do that with a program.

So I'm going to create a New Class and we'll call it ImageSaver.

And we'll go ahead and open the editor.

And let's make it bigger.

And what we'll do is we'll create a method in here called doSave, so,

And what we're gonna do is we're gonna use our directory resource that we

learned about.

So I'm going to create, if I can spell it right.

I'll create a variable called dr of type DirectoryResource.

And I'll have to create a new DirectoryResource.

And then we will like to loop over and pick up select files from there.

So we'll create a for loop and a variable f which is of type file.

And we'll use the selectedFiles method from the DirectoryResource.

And let's see what we're gonna do with our files.

So, now what we're gonna do is create an ImageResource.

I'm gonna create a variable of type ImageResource called image.

And that we will have to create a new ImageResource.

And we'll use the variable f that we read in in our for

loop, and I want to just make sure this works.

So what I'm gonna do now is just go ahead and have the image just draw.

And so we'll just draw it on the screen and see if this works.

All right, so let's see if this works.

I'm gonna try and compile it.

And nope, I've got an error.

So, let's see what it is.

So I forgot to put another curly brace.

Whenever you get this reached end of file while parsing and

it's got this highlighted.

So I'm gonna try and add another curly brace, I need one for my method doSave.

So let's put that in there.

That looks better.

You can also tell the way the colors are lined up that I was missing that.

So we'll compile it.

Okay, so, it's still not compiling because it doesn't know what DirectoryResource is.

So I have to import the edu.duke library,

so I'll add that right here,

import edu.duke.store and

that should fix that error.

So, let's compile again.

Now it can't find file.

So I'm also gonna have to import from the java.io library.

And I'll just go ahead and specify that I want to import the file class and

let's see if that compiles.

Yay, no syntax errors.

Okay, so now we can come over here and we can actually run this and just see.

All this is gonna do,

hopefully if it works, is it will just display some images that I'm gonna select.

So we will go ahead and create a New Image Saver.

And then, we will go ahead and run our doSave method.

Now I have to find on my computer where I've got some images.

So I'm gonna navigate to here.

And I've got it on my desktop, I've got a folder of images.

There it is.

And now I can select several images.

I'll just go ahead and select the dinos.

And I'll select another one, eastereggs.

I could select as many as I wanted to.

And I'll go ahead and open, and our program should just draw these images.

And it did. We saw the two images.

So, that's great.

That seemed to work.

I'll just get rid of those.

And let's go back to our program now, and now what we would like to do,

we know that we can get the images and we can display them.

And so now what we'd like to do is we'd like to make a copy of them, so

we're gonna add some more code in here.

And let's see, okay.

So now what we're gonna do is, first, what we have to do is we're gonna

get a file name from the image file that we have just grabbed.

So, I'm gonna create a string for that file name.

And we'll just call that fname.

So, the image, we can use the ImageResource

method that is called getFileName.

And if you didn't know about that you can look in the documentation and

you'll see all kinds of methods that you can use with the ImageResource class.

So just getFileName should get me a string.

And then what we wanna do is we wanna create a new name which is gonna be like

copy with the old name.

So let's create another string variable.

This will be called the newName.

And it's gonna be, let's make this string copy-.

And then we'll add that to the front of the file name, and

the rest of the file name will be the old file name.

So let's see, we will call this, fname is the old name.

So we've created, all we've done so far, well let's try and run this.

Let's see if this works.

So if I will just compile this.

It compiled with no errors, so let's just run it.

We'll come back over here.

We will create a New Image Saver.

And we'll come over here, and run our doSave method.

We can now go pick some files.

We have to navigate over to the desktop where my images are in the Images folder.

And I can grab, let's see, dinos and eastereggs again.

There we go.

And we open them.

And we got them, and now I also have the Images folder right here, so

we can just look and see.

We created a new name that was copy of, and

if we look in the folder, I don't see any image that's called copy dinos.

So we created a string, but

we didn't actually use the string to create a new file yet.

So let's do that.

So we have the name but now we need to use it.

So we're going to, actually, there's another method called setFileName.

So let's use that.

So we'll say image.setFileName,

and what we want to set it to is this new string that we created.

So let's do that, it's called newName.

So that should do it, and now also what we didn't do is we didn't save the file.

So we have drawn the file, but

there's also a method in the ImageResource class called save.

So let's do that too.

We'll draw it and we'll save it.

And that should save the new file.

So let's run this and see if this works.

We'll compile it.

And then we will come over here and run the program.

So we'll create a New Image Saver.

And then we'll run our doSave method.

We have to find some images.

Okay, and so again, I'll just pick dinos and

eastereggs, and let's open them.

Okay, so, they're displaying again, but how do we know if it worked?

Let's go look in the Images folder, which is right here.

And if you look in there, you'll see there are two new files in there.

One is called copy-dinos and the other is called copy-eastereggs.

So it looks like they copied them.

Now let's see what happens if we run our program again and

we select one of those, or both of those, even.

So let me get rid of these old images.

And let's just run our program again.

So, I'm running the doSave method.

I'm going to the desktop, picking some images to make copies of.

And I'm just gonna make a copy of copy-dinos.

And let's make a copy of copy-eastereggs, and

we'll also make a copy of, let's see, rodger.

All right, so we're gonna make a copy of those three files.

And let's see what happens.

Okay, so we had all those pictures pop up.

And we'll just get rid of them.

And if we look over here in the Images folder, let's see what we have.

We have copy-copy-dinos, and we have copy-copy-eastereggs,

because we made copies of copies, is what we did.

And then we also made a copy of rodger, so we also see copy-rodger.

So anyway, that's how you make a copy of an image, where we grab the file, we have

to create a new file name, and then we save a copy of it with the new file name.

But we have to give it a new name, cuz there's already a file with that name, so

we added copy- onto the front of it.

Hope you enjoyed that.

Thanks.

Coursera 카탈로그 살펴보기

무료로 참여해 맞춤화된 추천, 업데이트 및 제안을 받아보세요.

Coursera는 세계 최고의 교육에 대한 보편적인 접근 기회를 제공하며, 최고의 대학 및 기관들과 제휴하여 온라인 강좌를 제공합니다.

© 2019 Coursera Inc. All rights reserved.

앱스토어에서 다운로드하기

구글 플레이에서 받기

Coursera
소개
리더십
직업
카탈로그
수료증
MasterTrack™ 수료증
학위
포 엔터프라이즈 (For Enterprise)
정부용

커뮤니티
Learners
Partners
Developers
Beta Testers
Translators

연결
블로그
Facebook
Linkedin
Twitter
Instagram
YouTube
기술 블로그

기타
조건
개인정보 보호
도움말
접근성
보도 자료
문의하기
디렉토리
계열사