Java中的Scanner是否足以读取文本文件中的输入？

Question

what i'm going to do

i'm going to build a phone book program in Java to do the following jobs:

1. read from two text files, instruction.txt and phonebook.txt
2. phonebook.txt includes some phone entry, each entry for a person
3. instruction.txt includes some instructions i would execute to phonebook.txt , such as add new entry, query an entry, delete an entry, etc.
4. for sure i would care about the output of my program, but for now, i focus on the input.

my problem

i want to use Scanner to do all the input jobs, read in all the strings stored in instruction.txt and phonebook.txt, but i doubt if i can handle all the difficult conditions. Conditions like how to correctly get each entry, and identify what it is.

for each phone book entry, five fields are needed: name , birthday , phone number , address , email . And name and birthday are compulsory for each entry.

for instructions, they are add , delete , save , read , query .

sample text files

here is a sample of instruction.txt :

add name Testing Three; birthday 13-05-1982; phone 12345677; address Address Three; email testing@gmail.com delete Testing One save

each entry is separated by one or more blank lines. here is a sample of phonebook.txt :

name Testing One

birthday 13-05-1980

phone 12345678

address Address One

email testing1@gmail.com

-----------this is a blank line -------------------------

name Testing Two

birthday 13-05-1981

phone 12345644

address Address Two

email testing2@gmail.com

Answer 1

Yes, Scanner is sufficient to do the reading, though you'd need to use it the right way.

Getting the entries is simply a matter of calling a Scanner.next... method, and you can deal with the optional fields using hasNext... .

(Hint: use one scanner to split into lines, and then a new scanner to split each line.)