java io流文件复制{拷贝}，只设计文件

代码：

package main.java.java02.IO;

import java.io.*;

/**
 * @author:Mr.wang
 * @date:2019/2/21 0021 上午 10:00
 */
public class fuzhiwenjian02 {
    public static void main(String args[]) {
        //选择文件
        File src=new File("d:/a/a.txt");
        File dest=new File("d:/a/b.txt");
        //选择流
        try {
            InputStream is=new FileInputStream(src);
            OutputStream os=new FileOutputStream(dest);
            //拷贝  循环+读取+写出
            byte[]flush=new byte[1024];
            int len=0;
            //读取
            while(-1!=(len=is.read(flush))){
                //写出
                os.write(flush,0,len);
            }
            os.flush();//强制刷出
            //关闭流  先打开后关闭
            os.close();
            is.close();

        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

提取方法，之后直接使用：

public class fuzhiwenjian02 {
    public static void main(String args[]) {
        String src="d:/a/a.txt";
        String dest="d:/a/b.txt";
        copyFile(src,dest);
    }
    //提取方法
    public static void copyFile(String srcPath, String destPath) throws IOException {
        File src=new File(srcPath);
        File dest=new File(destPath);

        //选择流
        try {
            InputStream is=new FileInputStream(src);
            OutputStream os=new FileOutputStream(dest);
            //拷贝  循环+读取+写出
            byte[]flush=new byte[1024];
            int len=0;
            //读取
            while(-1!=(len=is.read(flush))){
                //写出
                os.write(flush,0,len);
            }
            os.flush();//强制刷出
            //关闭流  先打开后关闭
            os.close();
            is.close();

        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

优化：

package main.java.java02.IO;

import java.io.*;

/**
 * @author:Mr.wang
 * @date:2019/2/21 0021 上午 10:00
 */
public class fuzhiwenjian02 {
    public static void main(String args[]) {
        String src = "d:/a/a.txt";
        String dest = "d:/a/b.txt";
        try {
            copyFile(src, dest);
        }
        catch (FileNotFoundException e) {
            e.printStackTrace();
            System.out.println("文件不存在");
        }catch (IOException e){
            e.printStackTrace();
            System.out.println("拷贝失败!");
        }
    }

    //整理方法
    public static void copyFile(String srcPath, String destPath) throws IOException {
        File src=new File(srcPath);
        File dest=new File(destPath);
        if(!src.isFile()){
            System.out.println("只能拷贝文件！");
            return;
        }

        //选择流
            InputStream is = new FileInputStream(src);
            OutputStream os = new FileOutputStream(dest);
            //拷贝  循环+读取+写出
            byte[] flush = new byte[1024];
            int len = 0;
            //读取
            while (-1 != (len = is.read(flush))) {
                //写出
                os.write(flush, 0, len);
            }
            os.flush();//强制刷出
            //关闭流  先打开后关闭
            os.close();
            is.close();
        }
    }