Java 文件的输入与输出

采用主要的几种文件流

 

 

FileOutputStream、FileInputStream

import java.io.*;
public class Filetest{
	public static void main(String[] args){
		File file = new File("E:/myhomework/FileOutputStreamç±»","out.txt");
		File file1 = new File("E:/myhomework/FileOutputStreamç±»","in.txt");
		try{
			FileOutputStream out = new FileOutputStream(file);
			FileInputStream in = new FileInputStream(file1);
			byte byt[] = new byte[1024];
			int len = in.read(byt);
			System.out.println(new String(byt,0,len));
			in.close();
			//byte b[] = "123".getBytes();
			out.write(byt);
			out.close();
		}catch(Exception e){
			e.printStackTrace();
		}
	}
}

BufferedReader、BufferedWriter：

import java.io.*;

public class Filetest{
	public static void main(String[] args){
		File file = new File("E:/myhomework/BufferedReaderç±»","out.txt");
		File file1 = new File("E:/myhomework/BufferedReaderç±»","in.txt");
		try{
			FileWriter fw = new FileWriter(file);
			FileReader fr = new FileReader(file1);
			BufferedReader bufr = new BufferedReader(fr);
			BufferedWriter bufw = new BufferedWriter(fw);
			int i = 0;
			String s = new String("");
			while((s=bufr.readLine())!=null){
				
				System.out.println(s);
				bufw.write(s);
				bufw.newLine();
			}
			bufw.close();
			fw.close();
			bufr.close();
			fr.close();
		}catch(Exception e){
			e.printStackTrace();
		}
	}
}

BufferedInputStream、BufferedOutputStream：

import java.io.*;

public class Filetest{
	public static void main(String[] args){
		try{
			FileOutputStream fout = new FileOutputStream("E:\\myhomework\\BufferedInputStreamç±»\\out.txt");
			BufferedOutputStream bout = new BufferedOutputStream(fout);
			FileInputStream fin = new FileInputStream("E:\\myhomework\\BufferedInputStreamç±»\\in.txt");
			BufferedInputStream bin = new BufferedInputStream(fin);
			String content =new String("");
			byte[] buffer = new byte[1024];
			int flag = 0;
			while((flag = bin.read(buffer))!=-1){
				content+=new String(buffer, 0, flag);
			}

			System.out.println(content);
			bout.write(content.getBytes(),0,content.getBytes().length);
			bout.flush();
			bout.close();
			bin.close();
		}catch(Exception e){
			e.printStackTrace();
		}
	}
}

FileWriter、FileReader： 

import java.io.*;

public class filetest{
	public static void main(String[] args){
		FileReader reader = null;
		FileWriter writer = null;
		try{
			reader = new FileReader("E:\\myhomework\\FileReader类\\in.txt");
			writer = new FileWriter("E:\\myhomework\\FileReader类\\out.txt");
			char[] cbuf = new char[1024];
			while(reader.read(cbuf)!=-1){
				System.out.println(cbuf);
				writer.write(cbuf);
			}
			writer.flush();
		}catch(IOException e){
			e.printStackTrace();
		}finally{
			if(reader!=null){
				try{
					reader.close();
				}catch(IOException e){
					//关闭失败，通知上层；
					throw new RuntimeException("关闭流失败！");
				}
			}
			if(writer!=null){
				try{
					writer.close();
				}catch(IOException e){
					throw new RuntimeException("关闭流失败");
				}
			}
		}
	}
}