Study Number: 201621123032 Java programming 12th Week of study summary

1: Study Summary of the Week 1.1: summarize multi-stream and file-related content in the way you like (mind map or other).

2: System-oriented integrated design-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?

Compared to the last book information stored in the HashMap, this time the use of streams and files to put the book information in the file, but also from the file read information.
The file format is:. txt.

2.2: Brief description of the file read and write section of the system uses the stream and file-related interfaces and classes? Why use these interfaces with classes?

Use the character output stream: Filewriter,bufferedwriter. Character input stream: FileReader, BufferedReader

• FileWriter: Create file character output stream
• BufferedWriter: encapsulating the output stream with buffered data streams
• FileReader: Create file character input stream

• BufferedReader: encapsulating an input stream with buffered data streams
  In order to read the information from the file and write the new information to the file.

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

  Store the contents of the book in a file:
  

Query a book information:

Delete a line of information in a file: Store the information in a dynamic array and rewrite the file information.

Some features are not yet

There are implementations.
Operation Result:

3: Code Volume statistics

Week Time	Total code Amount	new increase in code volume	Total Folder	Add new Folder
1	114	114	11	11
2	520	50W	16	6
3	1089	569	22	6
5	1425	336	29	7
6	1819	394	31	2
7	2987	1168	54	23
8	5437	2450	79	25
9	5695	258	84	5
10	6680	985	102	18
11	6935	255	111	9
12	7401	466	123	12
13	8899	1498	141	18

4: Optional 4.1: Character stream with text file: Using PrintWriter (Write), BufferedReader (read) 1: Generated three student objects, Use PrintWriter's println method to write to 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)

Operation Result:

2: How much is the generated file size (using the right-click File Properties view)? Analyze the file size

16 bytes per line
Num:2, Name:4, Age:2,grade:5 separator: 3

4.2: Buffer Stream 1: Use PrintWriter to write 10 million lines to the file (whatever content), and then compare the use of BufferedReader and using scanner to read the data from the file speed (read only, not output), 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

Using BufferedReader faster, bufferedreader using buffering can reduce the number of Io, so the read speed is faster.

Time Comparison:

4.3:1: Existing EncodeTest.txt file, contains some Chinese, the file is encoded using UTF-8. Use FileReader and BufferedReader to read the EncodeTest.txt text into and out. Do you have garbled characters? Why does it have garbled characters? How to solve? (Key code, occurrence number)

will be garbled, because the file is UTF-8 encoded, but the read encoding is used GBK.

Workaround: Use UTF-8 encoding whenever code reads

Operation Result:

Study Number: 201621123032 Java programming 12th Week of study summary