java中io操作小例子

jinzq 2007-05-22

展开全文

//示例1,file基本操作

import java.io.File;
import java.io.IOException;
class FileDemo{
public static void main(String args[]){
  try{
   File file=new File("file1.txt");

   System.out.println("文件是否存在: "+file.exists());

   System.out.println("是文件吗: "+file.isFile());

   System.out.println("是文件夹吗: "+file.isDirectory());

   System.out.println("是否隐藏: "+file.isHidden());

   System.out.println("名称: "+file.getName());
   System.out.println("标准文件名: "+file.getCanonicalFile());

   System.out.println("相对路径: "+file.getPath());
   System.out.println("绝对路径: "+file.getAbsolutePath());
   System.out.println("标准路径: "+file.getCanonicalPath());

   System.out.println("最后修改时间: "+file.lastModified());

   System.out.println("文件大小: "+file.length()+" 字节");


  }

  catch(IOException ex){
   ex.printStackTrace();
  }
}
}

//示例2,简单读写操作

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileWriter;
import java.io.FileReader;
import java.io.IOException;
class BufferedReaderAndBufferedWriterTest{
public static void main(String args[]){
  try{
   FileWriter fw=new FileWriter("file1.txt");
   BufferedWriter bw=new BufferedWriter(fw);
   bw.write("大家好,我正在学习Java");
   bw.newLine();
   bw.write("请多多指教");
   System.out.println("file1.txt写入成功!***************开始读..\n");
   bw.flush();
   bw.close();

   FileReader fr=new FileReader("file1.txt");
   BufferedReader br=new BufferedReader(fr);
   String temp=null;
   do{
    temp=br.readLine();
    System.out.println(temp==null?"":temp);
   }
   while(temp!=null);
   fr.close();
   br.close();

   System.out.println("file1.txt已经读完!***************");
  }

  catch(IOException ex){
   ex.printStackTrace();
  }
}
}