java學習【檔案IO】，java學習io

java學習【檔案IO】，java學習io

部落格:http://blog.csdn.net/muyang_ren

1.快速讀取一個文字檔，將檔案的內容輸出到一個新檔案；

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.列出某一目錄下的尾碼為”.java”的檔案清單

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("開啟目錄失敗!");        }       }}

3.複製圖片檔案

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();        }    }}