Java Programming io simple review and learning

Java Programming IO operation is essential, long time not to play Io, review, write a few small programs, record, easy to access and learn.

1. Give an array of integers, write them to a file, read them from the file, and print in reverse order of integer size.

 Packagecom.io.test;ImportJava.io.BufferedReader;ImportJava.io.File;ImportJava.io.FileInputStream;ImportJava.io.FileReader;ImportJava.io.FileWriter;Importjava.io.IOException;ImportOrg.apache.jasper.tagplugins.jstl.core.ForEach; Public classSortandprint {//gives an array of integers, writes them to a file, reads them from a file, and prints in reverse order of integer size.          Public Static voidMain (string[] args)throwsIOException {int[] arr={3,4,6,78,90,1}; //Create a new fileFile file=NewFile ("D:\\sort.txt"); FileWriter FW=NewFileWriter (file); String String="";  for(inti = 0; i < arr.length; i++) {            intnum =Arr[i]; String+=num+ ",";                } System.out.println (String); Try{fw.write (string);        Fw.flush (); } Catch(IOException e) {e.printstacktrace (); }finally{            Try{fw.close (); } Catch(IOException e) {//TODO auto-generated Catch blockE.printstacktrace (); }        }        //read from FileFileReader fr=Newfilereader (file); BufferedReader BFR=NewBufferedReader (FR); StringBuilder SB=NewStringBuilder (); intCH = 0; String Str=NULL;  while((Str=bfr.readline ())! =NULL) {sb.append (str);         } fr.close ();        Bfr.close (); String[] Split= Sb.tostring (). Split (","); int[] INTs =Stringtoint (split); //to sort        int[] Sort2 =sort (ints);  for(inti = sort2.length-1; i>0; i--) {System.out.println (sort2[i]); }    }    //converting a string array to an array of integers     Public Static int[] Stringtoint (string[] strs) {intnum=strs.length; int[] arrs=New int[num];  for(inti = 0; i < strs.length; i++) {Arrs[i]=Integer.parseint (Strs[i]); }        returnArrs; }    //Bubble Sort     Public Static int[] Sort (int[] arr) {        intnum=arr.length; intTemp=0;  for(inti = num-1; i>0; i--) {             for(intj=0;j<i;j++){                //Bubbling Method                if(arr[j]>Arr[i]) {                    //Swap Positiontemp=Arr[j]; ARR[J]=Arr[i]; Arr[i]=temp; }            }        }        returnarr; }        }

2. Traverse all the files in a folder.

 Packagecom.io.test;ImportJava.io.File; Public classFilebianli {//traverse all files in a folder     Public Static voidMain (string[] args) {//get the Directory folder to traverseFile file=NewFile ("e:\\");    Showallfile (file); }         Public Static voidshowallfile (file file) {//get all child filesfile[] Files =File.listfiles (); //determine file type        if(!file.isdirectory ()) {System.out.println ("File:" +File.getabsolutepath ()); }Else{            if(files==NULL|| Files.length==0) {System.out.println ("Empty directory:" +File.getabsolutepath ()); }Else{                //Traverse FilesSystem.out.println ("Directory:" +File.getabsolutepath ());  for(File f:files) {showallfile (f); }            }        }            }}

Java Programming io simple review and learning