java写入

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.FileWriter;
import java.io.InputStreamReader;
import java.nio.channels.FileChannel;
import java.nio.ByteBuffer;

public class Test{
public static void main(String[] args) throws Exception {
      //创建2个文件
   File file1 = new File("D://test1.txt");
   File file2 = new File("d://test2.txt");
   file1.createNewFile();
   file2.createNewFile();
  
   //从键盘输入的字符写入test1.txt
   FileWriter fout = new FileWriter(file1);
   String str=null;
   System.out.println("Please input a String:");
   BufferedReader fin = new BufferedReader(new InputStreamReader(System.in));
   str = fin.readLine();
   System.out.println(str);
   fout.write(str,0,str.length());
   fout.flush();
   fout.close();
   fin.close();
  
   //复制文件test1.txt的内容到test2.txt
   //为了让你明白通道所以我这里用了2种读写入文件的方法
   new Exam2().copy("D://test1.txt", "d://test2.txt");
  
}
/**
  * 复制文件封装类
  * @param url1
  * @param url2
  * @throws Exception
  */
public void copy(String url1, String url2) throws Exception {
  FileInputStream input = new FileInputStream(url1);
  FileChannel filechannel = input.getChannel();
  FileOutputStream output = new FileOutputStream(url2);
  FileChannel filechannel2 = output.getChannel();
  ByteBuffer buf = ByteBuffer.allocate(1024 * ;
  while (filechannel.read(buf) != -1) {
   buf.flip();
   filechannel2.write(buf);
   buf.clear();
  }
  input.close();
  filechannel.close();
  output.close();
  filechannel2.close();
}
}