I-O流 file文件复制

package com.copyfile;
/**
 * 复制文档
 * 
 */
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;

public class CopyFile {
    public static void main(String[] args) {
        FileInputStream fis = null;//创建一个输入流
        FileOutputStream fos = null;//创建一个输出流
        String str = "";
        try {
            fis = new FileInputStream("D:/HelloWorld/Hello.java.txt");
            fos = new FileOutputStream("D:/HelloWorld/CopyFile.txt");
            //读取文件内容存入str
            int temp = -1;
            while((temp = fis.read())!=-1) {//读取完毕文件内容后的值为-1
                str += (char)temp;
            }
            System.out.println("文档已读取完毕！");
            //将读取文件放在bytes数组中
            byte[] bytes = str.getBytes();
            //复制读取到的文件
            fos.write(bytes);
            System.out.println("文档已复制");
            fos.flush();

        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                fos.close();
                fis.close();
            } catch (IOException e) {
                e.printStackTrace();
            }

        }
    }
}