201621123034 Java programming 12th Week of study summary

Job 12-Stream with file 1. This week's study summary 1.1 summarizes multi-stream and file-related content in the way you like (mind mapping or other).

2. System-oriented integrated design-Library management system or shopping cart

Use streams and files to transform your library management system or shopping cart.

2.1 A brief description of how to use streams and files to transform your system. What is the format of the data in the file?

A: Books and User both are objects, so use the object stream to write to the ObjectOutputStream file separately, and write a method to save the modified file. The file format written with the object stream is hexadecimal.

2.2 Brief description of what interfaces and classes are used in the file reading and writing section of the system with the stream associated with the file? Why use these interfaces with classes?

A: Interfaces InputStream , OutputStream their ObjectInputStream and ObjectOutputStream subclasses, and file classes are used File . In order to ensure that the object is written to the file, and can be read from the file into the program.

2.3 Read and write file-related code. Critical lines need to be annotated.

For:

3. Code volume Statistics 3.1 Statistics the amount of code completed this week

The weekly code statistics need to be fused into a single table.

Week Time	Total code Amount	New Code Volume	total number of files	number of new files
2	141	141	6	6
3	445	380	10	3
5	871	426	16	6
6	1496	623	26	10
7	2570	1076	40	14
8	2674	104	46	6
9	2997	323	53	7
10	3313	316	58	5
11	3724	411	68	10
12	4249	525	78	10
13	4540	291	87	9

Option: 4. Flow and Document Learning Guide (the job content is all selected at the bottom) 1. Character stream with text file: Use PrintWriter (write), BufferedReader (Read)

Writes the Student object (property: Int id, String name,int age,double grade) to the file Student.data, read from the file display.

1.1 Generated three student objects, using PrintWriter's Println method to write Student.txt, one student per line, and each student's attribute separated by |. Use scanner or BufferedReader to read the Student.txt data. (Key code, occurrence number)

For:

1.2 What is the size of the generated file (using the right-click File Properties view)? Analyze the file size

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1.3 If the println method of PrintWriter is called, but not close at the back. What is the file size? Why?

• Reference: Topic specific requirements see flow and document Experimental task book-title 1-2.1
• Reference code:TextFileTest.java

2. Buffer Stream 2.1 Use PrintWriter to write 10 million lines to a file (whatever it is), and then compare the speed (read only, not output) of using BufferedReader to read data from the file using scanner, which method is used fast? Intercept the test source code, the number of the study. Please analyze the reasons in detail. Tip: You can use JUNIT4 to compare run times

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2.2 Replace the PrintWriter with BufferedWriter to see if the speed of writing to the file has improved. Record the elapsed time of both. Try to analyze the reason.

• Reference: Subject specific requirements see flow and Document Experiment Task Book-topic 1-2.2 to 2.3
• Reference code:BufferedReaderTest.java

JUNIT4 frequently used annotations
JUNIT4 Learning
JUNIT4 Reference

201621123034 Java programming 12th Week of study summary