Java文件操作实例详细介绍

本文实例为大家分享了Java文件操作的具体代码，供大家参考，具体内容如下

简介

本程序主要采用了FileInputStream和FileOutputStream两类对文件进行操作。具体包括通过相对路径打开文件，三种方法读取文件，查看文件属性，追加文件数据等。

效果图：

完整代码：

package Code.a;
import java.io.*;
public class FileInputStreamDemo {
 

 public static void main(String[] args) {
  //获取当前目录;
  File f = new File(".");
  System.out.print("absolute path:"+f.getAbsolutePath()+"\n");
  while(true)
  {
   try {
    //输入命令；
    System.out.print("Please input your order：");
    BufferedReader stdinBufferedReader;
    String str1 = null;
    stdinBufferedReader = new BufferedReader(new InputStreamReader(System.in));
    str1 = stdinBufferedReader.readLine();
    //相对路径打开文件；
    File file2 = new File(".\\src\\Code\\a\\Exception.java");
    FileInputStream fis2 = new FileInputStream(file2);
    
    根据不同的命令，执行不同操作；
    //一次性读取全部数据
    if(str1.equals("一次性读取全部数据"))
    {
     byte[] buf = new byte[(int)(file2.length())];
     fis2.read(buf);
     String str = new String(buf);
     System.out.print(str);
     System.out.print("\n");
    }
    //分块读取
    else if(str1.equals("分块读取"))
    {
     int n = 1024,count;
     byte[] buf = new byte[n];
     while((count = fis2.read(buf)) != -1)
     {
      System.out.print(new String(buf,0,count));
     }
     System.out.print("\n");
    }
    //逐字读取数据
    else if(str1.equals("逐字读取数据"))
    {
     for(int i = 0; i < file2.length(); i++)
     {
      char ch = (char)(fis2.read());
      System.out.print(ch);
     }
     System.out.print("\n");
    }
    //退出
    else if(str1.equals("退出"))
    {
     System.out.print("已退出\n");
     break;
    }
    //查看文件属性
    else if(str1.equals("查看文件属性"))
    {
     System.out.print("If the file or catalog exists:"+file2.exists()+"\n");
     System.out.print("If is it a file:"+file2.isFile()+"\n");
     System.out.print("If is it a catalog:"+file2.isDirectory()+"\n");
     System.out.print("FileName:"+file2.getName()+"\n");
     System.out.print("absolute path:"+file2.getAbsolutePath()+"\n");
     System.out.print("The last time that the file was changed:"+file2.lastModified()+"\n");
     System.out.print("The size of the file:"+file2.length()+" bites\n");
    }
    //向文件追加数据
    else if(str1.equals("文件追加数据"))
    {
     FileOutputStream fos2 = new FileOutputStream(file2,true);
     System.out.println("Please input the content: ");
     BufferedReader ContentReader;
     String str2 = null;
     ContentReader = new BufferedReader(new InputStreamReader(System.in));
     str2 = ContentReader.readLine();
     fos2.write(str2.getBytes());
     fos2.close();
    }
    //关闭流对象；
    fis2.close();
   }
   //处理异常；
   catch(FileNotFoundException fnfe) {
    System.out.print("The file open unsuccessfully.");
   }catch(IOException ioe) {
    ioe.printStackTrace();
   }
  }
 }
 
}

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