Java 字节流数据拷贝性能测试

 

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package cn.edu.lcudcc.byte_buffer_time;   import java.io.*;   public class ByteBufferTimeDemo {     private static final String SRC_FILE = "/Users/baoshan/Downloads/线上教学截图/meeting_01.mp4";     private static final String DEST_FILE = "/Users/baoshan/Downloads/";       public static void main(String[] args) { //        copy01(); // 低级 字节流复制         copy02(); // 低级 字节数组流复制 //        copy03(); // 缓冲 字节流复制         copy04(); // 缓冲 字节数组流复制  效率高，优先使用     }       private static void copy01() {         long startTime = System.currentTimeMillis();         try{             InputStream is = new FileInputStream(SRC_FILE);             OutputStream os = new FileOutputStream(DEST_FILE+"video1.mp4");               int b;             while ((b = is.read()) != -1) {                os.write(b);             }             os.flush();             os.close();             is.close();         }         catch (Exception e){             e.printStackTrace();         }         long endTime = System.currentTimeMillis();         System.out.println("使用低级的字节流按照一个一个字节的形式复制文件耗时：" + (endTime - startTime) / 1000.0 + "s");     }       private static void copy02() {         long startTime = System.currentTimeMillis();         try {             InputStream is = new FileInputStream(SRC_FILE);             OutputStream os = new FileOutputStream(DEST_FILE + "video2.mp4");             byte[] buffer = new byte[1024];             int len;             while ((len = is.read(buffer)) != -1){                 os.write(buffer, 0, len);             }             os.flush();             os.close();             is.close();         }         catch (Exception e){             e.printStackTrace();         }         long endTime = System.currentTimeMillis();         System.out.println("使用低级的字节流数组按照一个一个字节的形式复制文件耗时：" + (endTime - startTime) / 1000.0 + "s");     }       private static void copy03() {         long startTime = System.currentTimeMillis();         try{             InputStream is = new FileInputStream(SRC_FILE);             BufferedInputStream bis = new BufferedInputStream(is);             OutputStream os = new FileOutputStream(DEST_FILE+"video3.mp4");             BufferedOutputStream bos = new BufferedOutputStream(os);               int b;             while ((b = bis.read()) != -1) {                 bos.write(b);             }             bos.flush();             bos.close();             bis.close();             os.close();             is.close();         }         catch (Exception e){             e.printStackTrace();         }         long endTime = System.currentTimeMillis();         System.out.println("使用缓冲的字节流按照一个一个字节的形式复制文件耗时：" + (endTime - startTime) / 1000.0 + "s");     }       private static void copy04() {         long startTime = System.currentTimeMillis();         try {             InputStream is = new FileInputStream(SRC_FILE);             BufferedInputStream bis = new BufferedInputStream(is);             OutputStream os = new FileOutputStream(DEST_FILE+"video4.mp4");             BufferedOutputStream bos = new BufferedOutputStream(os);               byte[] buffer = new byte[1024];             int len;             while ((len = bis.read(buffer)) != -1){                 bos.write(buffer, 0, len);             }             bos.flush();             bos.close();             bis.close();             os.close();             is.close();         }         catch (Exception e){             e.printStackTrace();         }         long endTime = System.currentTimeMillis();         System.out.println("使用缓冲的字节流数组按照一个一个字节的形式复制文件耗时：" + (endTime - startTime) / 1000.0 + "s");     }   }

　　

结论：高级缓冲字节数组流复制，效率最高，优先使用。