使用NIO与BIO复制文件性能对比

来源：互联网发布：云计算平台性能指标编辑：程序博客网时间：2024/05/01 07:05
package mr.mr03;import java.io.File;import java.io.FileInputStream;import java.io.FileOutputStream;import java.nio.ByteBuffer;import java.nio.channels.FileChannel;import org.junit.Test;public class CopyFileTest {@Testpublic void testBioCopyFile() throws Exception{long start = System.currentTimeMillis();File fromFile = new File("E:/live_sql/livesql/live-sql.2015-04-24.log");File toFile = new File("E:/live_sql/copy/live-sql.2015-04-24.log");if(!toFile.exists()){toFile.createNewFile();}FileInputStream fis = new FileInputStream(fromFile);FileOutputStream fos = new FileOutputStream(toFile);byte[] buf = new byte[1024 * 1024 * 100];int copyLen = -1 ;while((copyLen = fis.read(buf)) != -1){fos.write(buf, 0, copyLen); }fis.close();fos.close();long end = System.currentTimeMillis();System.out.println("耗时：" + (end - start) + "毫秒");   /** * 文件大小为458M * case1  * 当buf大小设置为 1024(1kb) 耗时：7290毫秒 * case2 *  当buf大小设置为1024*1024*10(10M) 耗时：659毫秒 * case3 *  当buf大小设置为1024*1024*100(100M) 耗时：5252毫秒 */}@Testpublic void testNioCopyFile() throws Exception{long start = System.currentTimeMillis();File fromFile = new File("E:/live_sql/livesql/live-sql.2015-04-24.log");File toFile = new File("E:/live_sql/copy/live-sql.2015-04-24.log");if(!toFile.exists()){toFile.createNewFile();}FileInputStream fis = new FileInputStream(fromFile);FileOutputStream fos = new FileOutputStream(toFile);FileChannel inputChannel = fis.getChannel();FileChannel outputChannel = fos.getChannel();ByteBuffer buf = ByteBuffer.allocateDirect(1024 * 1024) ;int readLen = -1 ;int writeLen = -1 ;while((readLen = inputChannel.read(buf)) != -1){buf.flip();writeLen = outputChannel.write(buf) ;if(writeLen != readLen){System.out.println("writeLen!=readLen，" + writeLen + "," + readLen);  }buf.clear();}inputChannel.close();outputChannel.close();fis.close();fos.close();long end = System.currentTimeMillis();System.out.println("耗时：" + (end - start) + "毫秒");   /** * 文件大小为458M * case1  *  ByteBuffer使用allocate分配1024字节  耗时：2234毫秒 * case2 *   ByteBuffer使用allocate分配1024 * 1024 (1M)  耗时：348毫秒 * case3 *  ByteBuffer使用allocateDirect分配1024 字节  耗时：2081毫秒 * case4 *  ByteBuffer使用allocateDirect分配1024 * 1024 (1M)  耗时：255毫秒 */}}
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