Java learning [file IO], java learning io

Java learning [file IO], java learning io

Blog: http://blog.csdn.net/muyang_ren

1. Read a text file quickly and output the file content to a new file;

package lhy.java_day3.oop;import java.io.BufferedReader;import java.io.BufferedWriter;import java.io.FileNotFoundException;import java.io.FileReader;import java.io.FileWriter;import java.io.IOException;public class Test_BuffeRead {    private static BufferedReader bfReader;    private static BufferedWriter bfWriter;    private static String str;    /**     * @param args     */    public static void main(String[] args) {        // TODO Auto-generated method stub        try {            bfReader = new BufferedReader(new FileReader("f:/java_day3.txt"));            bfWriter = new BufferedWriter(new FileWriter("f:/write.txt"));            while ((str=bfReader.readLine() )!= null) {                System.out.println(str);                bfWriter.write(str+"\r\n");                bfWriter.flush();            }        } catch (FileNotFoundException e) {            // TODO Auto-generated catch block            e.printStackTrace();        } catch (IOException e) {            // TODO Auto-generated catch block            e.printStackTrace();        }    }}

2. List the files suffixed with ". java" in a directory.

Package lhy. java_day3.oop; import java. io. file; public class Test_File {private static File fs;/*** @ param args */public static void main (String [] args) {String pathname = "e: \ test "; try {fs = new File (pathname); String [] str = fs. list (); for (String string: str) {if (string. endsWith (". java ") System. out. println (string) ;}} catch (NullPointerException e) {// TODO: handle exception System. out. Println ("failed to open the directory! ");}}}

3. Copy image files

package lhy.java_day3.oop;import java.io.FileInputStream;import java.io.FileNotFoundException;import java.io.FileOutputStream;import java.io.IOException;public class Test_picture {    private static FileInputStream fis;    private static FileOutputStream fos;    private static int ret;    private static byte[] b = new byte[2048];     /**     * @param args     */    public static void main(String[] args) {        // TODO Auto-generated method stub              try {            fis = new FileInputStream("f:\\tu1.jpg");            fos = new FileOutputStream("f:\\tu2.jpg");            while (true) {                ret = fis.read(b, 0, b.length);                if(ret!=-1){                    fos.write(b, 0, ret);                }else {                    break;                }                       }        } catch (FileNotFoundException e) {            // TODO Auto-generated catch block            e.printStackTrace();        } catch (IOException e) {            // TODO Auto-generated catch block            e.printStackTrace();        }    }}