java文件操作类实例

package com.pb.io.file;

import java.io.File;
import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.Date;

public class test1 {
	
	public static void main(String[] args) throws IOException {
		File file = new File("c:\\1.txt");
		if(!file.exists()){
			file.createNewFile();
		}
		System.out.println(file.getName());
		System.out.println(file.getAbsolutePath());
		System.out.println(file.getPath());
		System.out.println(file.exists()?"文件存在":"文件不存在");
		System.out.println(file.isDirectory()?"文件是目录":"文件不是目录");
		if(file.canRead()){
			System.out.println("当前文件可读");
		}else{
			System.out.println("当前文件不可读");
		}
		if(file.canWrite()){
			System.out.println("当前文件可写");
		}else{
			System.out.println("当前文件不可写");
		}
		//指定日期的格式
		SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd hh:mm:ss");
		Date date = new Date(file.lastModified());
		System.out.println(sdf.format(date));
		if(file.exists()){
			file.delete();
		}
		
	}

}

FileInputStram示例

package com.pb.io.inputstream;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileWriter;
import java.io.IOException;

public class FileInputStreamTest {

	public static void main(String[] args) throws IOException {
		File test= new File("c:\\1.txt");
		if(!test.exists()){
			test.createNewFile();
		}
		FileWriter Mywrier = new FileWriter(test);
		Mywrier.write("1223");
		Mywrier.close();
		//FileInputStream fis = new FileInputStream("c\\1.txt");
		//fis.close();
		FileInputStream fis = new FileInputStream("c:\\1.txt");
		int date;
		System.out.println("可读取文字数"+fis.available());
		System.out.println("文件内容");
		/*while((date=fis.read()) != -1){
			System.out.print(date+"");
		}*/
		while((date=fis.read()) != -1){
			System.out.print((char)(date)+"");
		}
		fis.close();

	}

}

FileOutPUtstream

package com.pb.io.outputstream;

import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;

public class FileOutPutstreamTest {

	public static void main(String[] args) throws IOException {
		FileOutputStream fos = new FileOutputStream("c:\\1.txt");
		String str="hao hao xu xi,day day up";
		//将字符串转换成数组
		byte[] words = str.getBytes();
		fos.write(words, 0, words.length);
		fos.close();
	}

}

如果文件不存在，则会一个个地写入，字符流，字节流

package com.pb.io.bufferwrite;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;

public class BufferTest {
	/*buffewrite
	 * 需要修笮到
	 * 
	 */
	
	
	public static void main(String[] args) throws IOException {
		//实例 化一个file wirte 对象
		FileWriter fw = new FileWriter("c:/1.txt");
		BufferedWriter bw = new BufferedWriter(fw);
		bw.write("大家好");
		bw.write("我要修改内容了");
		bw.newLine();
		bw.write("啥");
		bw.flush();
		bw.close();
		//fw.write("1231231");
		fw.close();
		FileReader fr = new FileReader("c:/1.txt");
		BufferedReader br = new BufferedReader(fr);
		int num =1;
		String line;
		while( (line = br.readLine()) !=null){
			System.out.println(line);
		}
		
	}

}

package com.pb.io.dataio;

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;

public class ReadAndWriteDate {
	public static void main(String[] args) throws IOException {
		//实例 fieoutputstream
		/**
		 * 使用dataoutputstream进行写操作
		 */
		FileOutputStream fos = new FileOutputStream("c:/1.txt");
		BufferedOutputStream bos = new BufferedOutputStream(fos);
		DataOutputStream dos = new DataOutputStream(bos);
		dos.writeByte(1);
		dos.writeLong(2);
		dos.writeChar('c');
		dos.writeUTF("fsadfa fsdafasdf");
		dos.close();
		bos.close();
		fos.close();
		/***
		 * datainputStream进行
		 */
		FileInputStream fis = new FileInputStream("c:/1.txt");
		BufferedInputStream bis = new BufferedInputStream(fis);
		DataInputStream dis = new DataInputStream(bis);
		System.out.println(dis.readByte());
		System.out.println(dis.readLong());
		System.out.println(dis.readChar());
		System.out.println(dis.readUTF());
		dis.close();
		bis.close();
		fis.close();
		
		
	}

}