简单I/O范例

package FileTest.Stream;

import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.File;

/**
 * Created by Mr.Wang on 2019/2/19.
 */
public class CopyFileTest {
    public static void main(String[] args) throws Exception{
        copyFile("I:\\StudySource\\text.txt","I:\\StudySource\\text2.txt");
    }

    public static void copyFile(String srcFile, String destFile) throws Exception{
        File file1 = new File(srcFile);         //源文件
        File file2 = new File(destFile);        //目标文件

        if (!file1.exists()){                   //判断源文件是否存在
            throw new Exception("源文件不存在");
        }
        if(!file2.exists()){                    //判断目标文件是否存在
            file2.createNewFile();
        }
        FileInputStream fileInputStream = new FileInputStream(srcFile);         //文件输入流
        FileOutputStream fileOutputStream = new FileOutputStream(destFile);     //文件输出流

        byte[] bytes = new byte[8*1024];                                        //单词读入的字节数组
        int end = bytes.length;                                                 
        while ((end = fileInputStream.read(bytes,0,end)) != -1){            //fileInputStream.read(bytes,0,end) 输入流将多个字节读入到数组中，返回读入的字节数
            fileOutputStream.write(bytes, 0, end);                          //输出流将数组中的字节读出到目标文件
        }

        fileInputStream.close();                                                //关闭流
        fileOutputStream.close();           
    }
}