jdbc - Why java throws exception java.lang.ArrayIndexOutOfBoundsException: 1 -

i have code reads data file , inserts database.

this code writes data file.

public void save(collection<book> b) {     try (printwriter print = new printwriter(this.file);) {         (book book : b) {             string str = book.getname() + "," + book.getauthor() + ","                     + book.getdate() + "\n";             print.println(str);         }     } catch (exception e) {     }  } 

this code writes data file , inserts db.

try(reader reader = new filereader(this.file);             bufferedreader br = new bufferedreader(reader)) {         connection = drivermanager.getconnection(                 "jdbc:mysql://localhost:3306/mybook", this.username,                 this.pass);          statement statement = connection.createstatement();         string str;                   while((str = br.readline()) != null){              string[] array = str.split(",");             statement.executeupdate("insert mybook.book (name,author,pubdate) values('"+array[0]+"', '"+ array[1]+"', '"+array[2]+"')");         }      }  

but throws exception

java.lang.arrayindexoutofboundsexception 

what wrong?

do following:

1. check content of file, how many ',' char have in each line, should have @ least 2
2. check size of array, should @ least 3 in each read iteration, since accessing array[2]

it seems array @ line or iteration doesn't have 3 items, maybe 1 or two.

example:

line 1: aaa,bbb,ccc   //2 ',' => array={"aaa","bbb","ccc"} fine line 2: ddd,eee       //1 ',' => array={"ddd","eee"} causes                       // exception since array[2] not exist null line 3: empty         //0 ',' => array={} causes exception 

if not sure of happening run following code:

    try(reader reader = new filereader(this.file);             bufferedreader br = new bufferedreader(reader)) {         connection = drivermanager.getconnection(                 "jdbc:mysql://localhost:3306/mybook", this.username,                 this.pass);          statement statement = connection.createstatement();         string str;                   while((str = br.readline()) != null&&str.split(",").length>=3){              string[] array = str.split(",");             statement.executeupdate("insert mybook.book  (name,author,pubdate) values('"+array[0]+"', '"+ array[1]+"', '"+array[2]+"')");         }      } 

if above code run without error @ least 1 line doesn't have 2 ',' chars if application still firing same error else.