FileDemo

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintStream;
import java.io.PrintWriter;

/**
 * File
 */

/**
 * @author fhwei 2006-11-9 下午04:56:28
 */
public class FileDemo {

 String fileName = "e://file.txt";

 /**
  * @param args
  */
 public static void main(String[] args) {
  // TODO Auto-generated method stub
  FileDemo fd = new FileDemo();
  fd.fileInputStream();

 }

 /**
  * 文件输出流是用于将数据写入 File 或 FileDescriptor 的输出流 用于写入诸如图像数据之类的原始字节的流
  */
 void fileOutputStream() {
  try {
   FileOutputStream fos = new FileOutputStream(fileName);
   /* 创建新的打印流 */
   PrintStream ps = new PrintStream(fos);
   /* 打印字符串 */
   ps.println("This is written to a file");
   ps.close();
   fos.close();
  } catch (Exception e) {
   System.err.println("Error writing to file");
  }
 }

 /**
  *
  * 2006上午10:41:08
  */
 void WriteMyFile() {
  try {
   /* 在给出 File 对象的情况下构造一个 FileWriter 对象 */
   FileWriter fw = new FileWriter(fileName);
   /* 创建不带自动行刷新的新 PrintWriter */
   PrintWriter pw = new PrintWriter(fw);
   /* 打印 String，然后终止该行 */
   pw.println("hi,this will be wirte into the file!");
   pw.close();
   fw.close();
  } catch (IOException e) {
   System.out.println("Uh oh, got an IOException error!");
   e.printStackTrace();
  }
 }

 /**
  *
  * 2006上午10:41:16
  */
 void readMyFile() {
  String record = null;
  int recCount = 0;
  try {
   FileReader fr = new FileReader(fileName);
   /* 从字符输入流中读取文本，缓冲各个字符，从而提供字符、数组和行的高效读取 */
   BufferedReader br = new BufferedReader(fr);
   record = new String();
   /* 读取一个文本行 */
   while ((record = br.readLine()) != null) {
    recCount++;
    System.out.println(recCount + ": " + record);
   }
   br.close();
   fr.close();
  } catch (IOException e) {
   System.out.println("Uh oh, got an IOException error!");
   e.printStackTrace();
  }
 }

 /**
  *
  * 2006上午10:41:23
  */
 /* FileInputStream */
 void fileInputStream() {
  String record = null;
  try {
   FileInputStream fstream = new FileInputStream(fileName);
   BufferedReader d = new BufferedReader(
     new InputStreamReader(fstream));
   while ((record = d.readLine()) != null) {
    System.out.println(record);
   }
   d.close();
   fstream.close();
  } catch (Exception e) {
   System.err.println("File input error");
  }
 }

 /**
  *
  * 2006上午10:41:32
  */
 void file() {
  File file2 = new File("E://");
  /* 列出目录下的所有文件 */
  File[] file3 = file2.listFiles();
  for (int i = 0, j = file3.length; i < j; i++) {
   System.out.println("It ok!" + file3[i].getPath());

   File file = new File(fileName);
   /* 三种属性的获取 */
   String fileName = file.getName();
   String fileParent = file.getParent();
   String filePath = file.getPath();
   System.out.println("fileName:" + fileName + "/t" + fileParent
     + "/t" + filePath);
   /* 判断是否存在该文件 */
   if (!file.exists()) {
    System.out.println("It isn't exist!");
   }
   try {
    /* 如果不存在创建该文件 */
    file.createNewFile();
    boolean retValue = false;
    retValue = file.isFile();
    System.out.println("It ok!" + retValue);

   } catch (IOException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
   }

  }
 }
}