使用字符流拷贝数据时，需要注意在文件末尾处的数据，因为最后一次读取的长度不会刚好与数组input长度相同，所以需要引入新的变量来存储每次读取的长度。

import java.io.File;

import java.io.FileInputStream;

import java.io.FileNotFoundException;

import java.io.FileOutputStream;

import java.io.IOException;

import java.io.InputStreamReader;

import java.io.OutputStreamWriter;

import java.io.UnsupportedEncodingException;

public class RWByCharStream {

public static void main(String[] args) {

try {

//File file=new File("java.txt");

FileInputStream fis=new FileInputStream("java.txt");

InputStreamReader isr=new InputStreamReader(fis,"UTF-8");

FileOutputStream fos=new FileOutputStream("java_copy.txt");

OutputStreamWriter osw=new OutputStreamWriter(fos);

char input[]=new char[100];

int f=0;

while((f=isr.read(input))!=-1) {

//System.out.println(new String(input,0,f));

osw.write(input,0,f);

}

isr.close();

fis.close();

osw.close();

fos.close();

} catch (FileNotFoundException e) {

e.printStackTrace();

} catch (UnsupportedEncodingException e) {

e.printStackTrace();

} catch (IOException e) {

e.printStackTrace();

}

}

}

使用缓冲字符流读写数据：

import java.io.BufferedReader;

import java.io.BufferedWriter;

import java.io.File;

import java.io.FileInputStream;

import java.io.FileNotFoundException;

import java.io.FileOutputStream;

import java.io.IOException;

import java.io.InputStreamReader;

import java.io.OutputStreamWriter;

import java.io.UnsupportedEncodingException;

public class RWByBufferedCharStream {

public static void main(String[] args) {

try {

//File file=new File("java.txt");

FileInputStream fis=new FileInputStream("java.txt");

InputStreamReader isr=new InputStreamReader(fis,"UTF-8");

FileOutputStream fos=new FileOutputStream("java_copy_buffer.txt");

OutputStreamWriter osw=new OutputStreamWriter(fos);

BufferedReader br=new BufferedReader(isr);

BufferedWriter bw=new BufferedWriter(osw);

String input;

while((input=br.readLine())!=null) {

bw.write(input);

}

bw.close();

br.close();

isr.close();

fis.close();

osw.close();

fos.close();

} catch (FileNotFoundException e) {

e.printStackTrace();

} catch (UnsupportedEncodingException e) {

e.printStackTrace();

} catch (IOException e) {

e.printStackTrace();

}

}

}

拷贝的文件中没有换行，全在同一行。

import java.io.BufferedReader;

import java.io.BufferedWriter;

import java.io.File;

import java.io.FileInputStream;

import java.io.FileNotFoundException;

import java.io.FileOutputStream;

import java.io.IOException;

import java.io.InputStreamReader;

import java.io.OutputStreamWriter;

import java.io.PrintWriter;

import java.io.UnsupportedEncodingException;

public class RWByBufferedCharStream {

public static void main(String[] args) {

try {

//File file=new File("java.txt");

FileInputStream fis=new FileInputStream("java.txt");

InputStreamReader isr=new InputStreamReader(fis,"UTF-8");

FileOutputStream fos=new FileOutputStream("java_copy_buffer.txt");

OutputStreamWriter osw=new OutputStreamWriter(fos);

BufferedReader br=new BufferedReader(isr);

//BufferedWriter bw=new BufferedWriter(osw);

PrintWriter pw=new PrintWriter(osw);

String input;

while((input=br.readLine())!=null) {

//bw.write(input);

pw.println(input);

}

//bw.close();

pw.flush(); //将最后一次读取的内容从缓冲区读出来

pw.close();

br.close();

isr.close();

fis.close();

osw.close();

fos.close();

} catch (FileNotFoundException e) {

e.printStackTrace();

} catch (UnsupportedEncodingException e) {

e.printStackTrace();

} catch (IOException e) {

e.printStackTrace();

}

}

}

使用PrintWriter代替BufferedWriter，方便处理最后一次读取的内容和每行里的换行。