1
public class wori
{
public static void main(String args[])
{
FileWriter out = null;
FileReader in = null;
int b = 0;
int n = 0; //要是放到try里，最后一句无法通过，try也是作用域
try
{
in = new FileReader("d:/1.txt");
out = new FileWriter("d:/2.txt");
while((b = in.read()) != -1)
{
System.out.println(b);
n++;
out.write(b);
}
out.close();
in.close();
}
catch(FileNotFoundException e)
{
System.out.println("File not found");
System.exit(-1);
}
catch(IOException e)
{
System.out.println("File read error;");
System.exit(-1);
}
System.out.println("一共有" + n + "个数");
}
}
2
BufferedReader BufferedWriter
public class wori
{
public static void main(String args[])
{
try
{
BufferedWriter out = new BufferedWriter(new FileWriter("d:/2.txt")); //
BufferedReader in = new BufferedReader(new FileReader("d:/1.txt")); //
String s;
while((s = in.readLine()) != null) //readLine返回null
{
out.write(s);
out.newLine(); //
}
out.close();
in.close();
}
catch(IOException e)
{
System.out.println("File read error");
}
}
}
3
缓冲流InputStreamReader和OutputStreamWriter，可以实现一个字符一个字符的读写
public class wori { public static void main(String args[]) { try { OutputStreamWriter out = new OutputStreamWriter(new FileOutputStream("d:/1.txt")); // out.write("worinima"); out.close(); // out = new OutputStreamWriter(new FileOutputStream("d:/2.txt", true)); //true代表追加，不加true，原来的内容会被清除 out.write("cao"); out.close(); } catch(IOException e) { System.out.println("File read error"); System.exit(-1); } } }
原文：http://www.cnblogs.com/melon2014/p/3985146.html