JAVA input/output learning...

today we are doing exercises in the chapter I/O of Java programming ideology. Running the Program cannot output strings to files, it was discovered later that the program did not close the stream object at last...
Code :
public class iowork {
Public static void writefile () {
try {
filewriter fw = new filewriter ("iowriterfile.txt");
printwriter PW = new printwriter (FW );
for (INT I = 0; I system. out. print (I + ":" + v. get (I ). tostring () + "\ n");
PW. write (I + ":" + v. get (I ). tostring () + "\ n");
}< br> PW. flush (); -------------- 1
PW. close (); -------------- 2
}catch (ioexception e) {
// todo auto-generated Catch Block
E. printstacktrace ();
}< BR >}

if there is no statement at 1 or 2 in the Code, the data in the vector cannot be output to the file, because the printwriter object is not closed and the data is still in the memory, only when the flush () or close () method is called will the data in the memory be written to the file. As a good habit, when using stream objects, remember to close stream objects after they are used up.