[Java] FileReader 和 FileWrite 用法

import java.io.FileReader;
import java.io.FileWriter;

Reader rd = new FileReader("abc.txt");
Writer wt = new FileWriter("def.txt");

char[] ca = new char[1024];

int n=0,total=0;
while((n = rd.read(ca)) != -1){
  wt.write(ca, 0, n);
  total += n;
}

System.out.println("共有" + total + "字元");