Java Basics-Programming exercises (III)

Familiar with the use of the string method to determine whether the file name is legitimate

In addition to learning, write a little exercise to solidify the method of string application.

Task:

1. Determine the type of content that the user chooses to enter

2, if it is a Java file, output "you entered a Java filename"

3, if the email address, the output "you entered the email address"

4. If none, the output "cannot parse what you have entered"

The code is as follows:

1      Public Static voidMain (string[] args) {2Scanner in =NewScanner (system.in);3         BooleanFlag =true;4          Do {5SYSTEM.OUT.PRINTLN ("Please tell me what you want to know:");6String name =In.next ();7 8             Switch(Jude (name)) {9              Case1:TenSYSTEM.OUT.PRINTLN ("You have entered a Java file name"); OneFlag =false; A                  Break; -              Case2: -SYSTEM.OUT.PRINTLN ("You have entered an email address")); theFlag =false; -                  Break; -              Case-1: -SYSTEM.OUT.PRINTLN ("Cannot parse what you entered, please re-enter!") "); +                  Break; -             } +} while(flag); A in.close (); at     } -  -     /* - * Judging Format -      */ -     Private Static intJude (String Name) { in  -         intcount1 = 0;//the number of the string that contains the. to         intCount2 = 0;//contains the number of @ in the string +  -          for(inti = 0; I < name.length (); i++) {//Number of statistics the             if(Name.charat (i) = = '. ') { *count1++; $             }Panax Notoginseng             if(Name.charat (i) = = ' @ ') { -count2++; the             } +         } A         if(Count1 = = 1 && count2 = 1) { the             //get the location of the "@" symbol in the mailbox +             intIndex2 = Name.indexof (' @ ')); -             //get the "." In the mailbox Location of the number $             intIndex3 = Name.indexof ('. ')); $             if(Index2>0 && index3-index2> 1&&index3!=name.length ()-1) {//The judgment must contain the "@" symbol, and "@" must be in the "." Before -                  -                 return2; the             } -         }Wuyi         if(Count1 > 0) { the             //gets the name of the last occurrence of "." Location of the number -             intindex = Name.lastindexof ('. ')); Wu             //get the suffix of a file -String prefix =name.substring (index); About              $             //The judgment must contain the "." Number, and cannot appear in the first place, with the suffix named "java" -             if(Index! =-1 && Index! = 0 && prefix.equals (". Java")) { -  -                 return1; A             } +         } the         return-1; -  $}

Operation Result:

This is in accordance with my own understanding of the small program, mainly used to be familiar with the use of the method of the string class, there may be a lot to improve the place, if there are errors in the place please point out thank you!!

Java Basics-Programming exercises (III)