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JAVA IO性能比较

原创 Linux操作系统 作者：壹頁書 时间：2013-11-09 12:05:08 0 删除 编辑
JAVA常用IO方式包括流,通道和MappedByteBuffer。
试验通过复制一个大文件（eclipse-jee-juno-SR2-win32.rar 237M）,并选择不同的缓冲区大小，记录复制的时间。
影响IO的因素有很多，同样的方式复制时间可能差异很大。所以需要排除一些最大和最小的数据，保证样本的正确性。

  1. import java.io.BufferedInputStream;
  2. import java.io.BufferedOutputStream;
  3. import java.io.File;
  4. import java.io.FileInputStream;
  5. import java.io.FileOutputStream;
  6. import java.io.IOException;
  7. import java.io.RandomAccessFile;
  8. import java.lang.reflect.InvocationHandler;
  9. import java.lang.reflect.Method;
  10. import java.lang.reflect.Proxy;
  11. import java.nio.ByteBuffer;
  12. import java.nio.MappedByteBuffer;
  13. import java.nio.channels.FileChannel;
  14. import java.nio.channels.FileChannel.MapMode;
  15. import java.util.Date;

  17. public class TestIO {
  18.     // 缓存大小
  19.     private static enum BufferSize {
  20.         _1M, _10M, _50M;

  22.         public static int getBufferSize(BufferSize bufferSize) {
  23.             if ("_1M".equals(bufferSize.toString())) {
  24.                 return 1024 * 1024;
  25.             } else if ("_10M".equals(bufferSize.toString())) {
  26.                 return 10 * 1024 * 1024;
  27.             } else if ("_50M".equals(bufferSize.toString())) {
  28.                 return 50 * 1024 * 1024;
  29.             }
  30.             return -1;
  31.         }
  32.     }

  34.     // 源文件
  35.     private static File source = new File("C:/Users/lihuilin/Desktop/eclipse-jee-juno-SR2-win32.rar");

  37.     // 复制文件接口
  38.     private static interface Copy {
  39.         void action() throws Exception;

  41.         BufferSize getBufferSize();
  42.     }

  44.     // 获取目标文件
  45.     private static File getTarget(Copy copy, BufferSize bufferSize) {
  46.         String target = "C:/tmp/" + copy.getClass().getSimpleName() + bufferSize.toString() + "_" + new Date().getTime() + ".rar";
  47.         return new File(target);
  48.     }

  50.     // 传统IO流复制方式
  51.     private static class Stream implements Copy {
  52.         BufferSize bufferSize;

  54.         public Stream(BufferSize bufferSize) {
  55.             this.bufferSize = bufferSize;
  56.         }

  58.         @Override
  59.         public void action() throws IOException {
  60.             BufferedInputStream in = new BufferedInputStream(new FileInputStream(source), BufferSize.getBufferSize(bufferSize));
  61.             BufferedOutputStream out = new BufferedOutputStream(new FileOutputStream(getTarget(this, bufferSize)));
  62.             byte[] buffer = new byte[BufferSize.getBufferSize(bufferSize)];
  63.             int length;
  64.             while ((length = in.read(buffer)) != -1) {
  65.                 out.write(buffer, 0, length);
  66.             }
  67.             out.flush();
  68.             in.close();
  69.             out.close();
  70.         }

  72.         @Override
  73.         public BufferSize getBufferSize() {
  74.             return bufferSize;
  75.         }
  76.     }

  78.     // NIO通道方式
  79.     private static class Channel implements Copy {

  81.         private BufferSize bufferSize;

  83.         public Channel(BufferSize bufferSize) {
  84.             this.bufferSize = bufferSize;
  85.         }

  87.         @Override
  88.         public void action() throws Exception {
  89.             FileChannel in = new FileInputStream(source).getChannel();
  90.             FileChannel out = new FileOutputStream(getTarget(this, bufferSize)).getChannel();
  91.             ByteBuffer buffer = ByteBuffer.allocate(BufferSize.getBufferSize(bufferSize));
  92.             while (in.read(buffer) != -1) {
  93.                 buffer.flip();
  94.                 out.write(buffer);
  95.                 buffer.compact();
  96.             }
  97.             in.close();
  98.             out.close();
  99.         }

  101.         @Override
  102.         public BufferSize getBufferSize() {
  103.             return bufferSize;
  104.         }
  105.     }

  107.     // MappedByteBuffer方式
  108.     private static class Mapped implements Copy {
  109.         private BufferSize bufferSize;

  111.         public Mapped(BufferSize bufferSize) {
  112.             this.bufferSize = bufferSize;
  113.         }

  115.         @Override
  116.         public void action() throws Exception {
  117.             FileChannel in = new RandomAccessFile(source, "r").getChannel();
  118.             FileChannel out = new RandomAccessFile(getTarget(this, bufferSize), "rw").getChannel();
  119.             long pos = 0;
  120.             long step = BufferSize.getBufferSize(bufferSize);
  121.             MappedByteBuffer inBuffer, outBuffer = null;
  122.             while (pos < in.size() && (in.size() - pos) > step) {
  123.                 inBuffer = in.map(MapMode.READ_ONLY, pos, BufferSize.getBufferSize(bufferSize));
  124.                 outBuffer = out.map(MapMode.READ_WRITE, pos, BufferSize.getBufferSize(bufferSize));
  125.                 outBuffer.put(inBuffer);
  126.                 pos = pos + step;
  127.                 inBuffer.clear();
  128.                 outBuffer.clear();
  129.             }

  131.             inBuffer = in.map(MapMode.READ_ONLY, pos, in.size() - pos);
  132.             outBuffer = out.map(MapMode.READ_WRITE, pos, in.size() - pos);

  134.             outBuffer.put(inBuffer);
  135.             inBuffer.clear();
  136.             outBuffer.clear();
  137.             in.close();
  138.             out.close();
  139.         }

  141.         @Override
  142.         public BufferSize getBufferSize() {
  143.             return bufferSize;
  144.         }

  146.     }

  148.     // 动态代理，用于记录复制时间并写入日志
  149.     private static class Watch implements InvocationHandler {
  150.         private Copy copy;

  152.         public Watch(Copy copy) {
  153.             this.copy = copy;
  154.         }

  156.         public Copy getInstance() {
  157.             return (Copy) Proxy.newProxyInstance(copy.getClass().getClassLoader(), copy.getClass().getInterfaces(), this);
  158.         }

  160.         @Override
  161.         public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
  162.             Object result;
  163.             long start = System.currentTimeMillis();
  164.             result = method.invoke(copy, args);
  165.             long end = System.currentTimeMillis();

  167.             String log = copy.getClass().getSimpleName() + ":" + copy.getBufferSize().toString() + ":" + (end - start) + "\n";
  168.             System.out.print(log);
  169.             FileOutputStream out = new FileOutputStream("C:/tmp/Log.txt", true);
  170.             out.write(log.getBytes());
  171.             out.flush();
  172.             out.close();
  173.             return result;
  174.         }
  175.     }

  177.     public static void main(String[] args) throws Exception {
  178.         for (int i = 0; i < 15; i++) {
  179.             new Watch(new Mapped(BufferSize._50M)).getInstance().action();
  180.             new Watch(new Mapped(BufferSize._10M)).getInstance().action();
  181.             new Watch(new Mapped(BufferSize._1M)).getInstance().action();

  183.             new Watch(new Channel(BufferSize._50M)).getInstance().action();
  184.             new Watch(new Channel(BufferSize._10M)).getInstance().action();
  185.             new Watch(new Channel(BufferSize._1M)).getInstance().action();

  187.             new Watch(new Stream(BufferSize._50M)).getInstance().action();
  188.             new Watch(new Stream(BufferSize._10M)).getInstance().action();
  189.             new Watch(new Stream(BufferSize._1M)).getInstance().action();
  190.         }
  191.     }
  192. }
将样本数据Log.txt挂载为Oracle的外部表，以便分析

  1. create table log
  2. (
  3.         copytype varchar2(10),
  4.         buffersize varchar2(10),
  5.         copytime varchar2(10)
  6. )
  7. organization external
  8. (
  9.         type oracle_loader
  10.         default directory tmp
  11.         access parameters
  12.         (
  13.                 records delimited by "\n"
  14.                 FIELDS TERMINATED BY ":" LDRTRIM
  15.                 REJECT ROWS WITH ALL NULL FIELDS
  16.                 (
  17.                         copytype CHAR(20) TERMINATED BY ":",
  18.                         buffersize CHAR(20) TERMINATED BY ":",
  19.                         copytime CHAR(20) TERMINATED BY ":"
  20.                 )
  21.         )
  22.         location ('Log.txt')
  23. );
查询样本数据，发现同样的方式，差异非常大。

SQL> select * from log where copytype='Channel' and buffersize='_1M';
COPYTYPE   BUFFERSIZE COPYTIME
---------- ---------- ----------
Channel    _1M        6896
Channel    _1M        9859
Channel    _1M        5711
Channel    _1M        6514
Channel    _1M        5400
Channel    _1M        5494
Channel    _1M        7052
Channel    _1M        5807
Channel    _1M        10904
Channel    _1M        13839
Channel    _1M        17035
Channel    _1M        6255
Channel    _1M        5085

已选择13行。

整理样本数据，将每种方式前五个数据和最后五个数据清除，并建立视图。

  1. create or replace view v1 as
  2. select copytype,buffersize,copytime from
  3. (
  4.     select copytype,buffersize,copytime,
  5.     row_number() over(partition by copytype,buffersize order by to_number(copytime)) c1,
  6.     row_number() over(partition by copytype,buffersize order by to_number(copytime) desc) c2
  7.     from log
  8. ) log where c1 not in (1,2,3,4,5) and c2 not in(1,2,3,4,5);
此时数据已经相差不大。
SQL> select * from v1;
COPYTYPE   BUFFERSIZE COPYTIME
---------- ---------- ----------
Channel    _10M       807
Channel    _10M       844
Channel    _10M       870
Channel    _1M        6255
Channel    _1M        6514
Channel    _1M        6896
Channel    _50M       12748
Channel    _50M       12865
Channel    _50M       12901
Mapped     _10M       11170
Mapped     _10M       16355
Mapped     _10M       17158
Mapped     _1M        1774
Mapped     _1M        1963
Mapped     _1M        4213
Mapped     _50M       472
Mapped     _50M       601
Stream     _10M       1047
Stream     _10M       1182
Stream     _10M       1436
Stream     _1M        7283
Stream     _1M        7347
Stream     _50M       28280
Stream     _50M       30288
Stream     _50M       31012

已选择25行。

使用行转列，查看平均时间。

  1. select copytype,
  2. round(avg(decode(buffersize,'_1M',copytime)),2) one,
  3. round(avg(decode(buffersize,'_10M',copytime)),2) ten,
  4. round(avg(decode(buffersize,'_50M',copytime)),2) fifty
  5. from v1 group by copytype;
COPYTYPE          ONE        TEN      FIFTY
---------- ---------- ---------- ----------
Channel          6555     840.33      12838
Mapped           2650   14894.33      536.5
Stream           7315    1221.67      29860



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