java - Read one line at time from a file when a function is called each time -
string time=read_one_line(); public static string read_one_line() throws filenotfoundexception, ioexception { fileinputstream fin=new fileinputstream("sample.txt"); bufferedreader br=new bufferedreader(new inputstreamreader(fin)); str=br.readline(); next_line=br.readline(); return next_line; } each time should read 1 line text file called "sample.txt" , return it. next time should return next line , on....
contents of sample.txt are:
date:0 year:0 hour:0 minute:0 seconds:0 milliseconds:310 date:0 year:0 hour:0 minute:0 seconds:0 milliseconds:0 date:0 year:0 hour:0 minute:0 seconds:0 milliseconds:10 date:0 year:0 hour:0 minute:0 seconds:0 milliseconds:0 date:0 year:0 hour:0 minute:0 seconds:0 milliseconds:380 date:0 year:0 hour:0 minute:0 seconds:10 milliseconds:-840 date:0 year:0 hour:0 minute:0 seconds:0 milliseconds:0 date:0 year:0 hour:0 minute:0 seconds:0 milliseconds:0 date:0 year:0 hour:0 minute:0 seconds:0 milliseconds:0 date:0 year:0 hour:0 minute:0 seconds:0 milliseconds:0 but rather reading , returning first line each time.. please tell me how increment next line , return when call function next time.
you creating new fileinputstream each time function called. therefore, file read beginning each time.
create bufferedreader once, outside of function , pass in on each call, file successively read.
public static string read_one_line(final bufferedreader br) throws ioexception { next_line=br.readline(); return next_line; } usage like
static void main(string args[]) throws ioexception { fileinputstream fin=new fileinputstream("sample.txt"); try { bufferedreader br=new bufferedreader(new inputstreamreader(fin)); string line = read_one_line(br); while ( line != null ) { system.out.println(line); line = read_one_line(br); } } { fin.close(); // make sure close file when we're done. } } note in case, read_one_line omitted , replaced simple br.readline().
if want every other line, can read 2 lines in each iteration, like
string line = read_one_line(br); while ( line != null ) { system.out.println(line); string dummy = read_one_line(br); line = read_one_line(br); }
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