文件读写操作
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2022-07-12 19:46:42
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import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.channels.FileChannel;
public class FileReaderAndWriter
{
public static void main(String[] args)
{
String srcFilePathName = "D:/test.txt";
String targetFilePathName = "z:/test.txt";
MultiFileOperation(srcFilePathName, targetFilePathName);
}
public static void MultiFileOperation(String srcFilePathName, String targetFilePathName)
{
/** 通过NIO实现文件读写方式1 */
FileInputStream fin1 = null;
FileOutputStream fout1 = null;
long start = 0;
try
{
fin1 = new FileInputStream(srcFilePathName);
fout1 = new FileOutputStream(targetFilePathName);
FileChannel fcin = fin1.getChannel();
FileChannel fcout = fout1.getChannel();
int fileLength = (int) fcin.size();
start = System.currentTimeMillis();
fcin.transferTo(0, fileLength, fcout);
}
catch (FileNotFoundException e)
{
e.printStackTrace();
}
catch (IOException e)
{
e.printStackTrace();
}
finally
{
try
{
fin1.close();
fout1.close();
}
catch (IOException e)
{
e.printStackTrace();
}
}
long end = System.currentTimeMillis();
long time1 = end - start;
System.out.println("NIO_time1: " + time1);
/** 通过NIO实现文件读写方式2 */
FileInputStream fin11 = null;
FileOutputStream fout11 = null;
try
{
fin11 = new FileInputStream(srcFilePathName);
fout11 = new FileOutputStream(targetFilePathName);
FileChannel fcin11 = fin11.getChannel();
FileChannel fcout11 = fout11.getChannel();
ByteBuffer buffer = ByteBuffer.allocate(512);
start = System.currentTimeMillis();
while (fcin11.read(buffer) != -1)
{
buffer.flip();
fcout11.write(buffer);
/** 从缓冲区写入数据之后调用此方法,以防写入不完整 */
buffer.compact();
buffer.clear();
}
}
catch (FileNotFoundException e)
{
e.printStackTrace();
}
catch (IOException e)
{
e.printStackTrace();
}
finally
{
try
{
fin11.close();
fout11.close();
}
catch (IOException e)
{
e.printStackTrace();
}
}
end = System.currentTimeMillis();
long time11 = end - start;
System.out.println("NIO_time2: " + time11);
}
}
import java.io.BufferedOutputStream;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.channels.FileChannel;
public class FileReaderAndWriter
{
public static void main(String[] args)
{
String srcFilePathName = "D:/test.txt";
String targetFilePathName = "z:/test.txt";
MultiFileOperation(srcFilePathName, targetFilePathName);
}
public static void MultiFileOperation(String srcFilePathName, String targetFilePathName)
{
/** 通过NIO实现文件读写方式1 */
FileInputStream fin1 = null;
FileOutputStream fout1 = null;
long start = 0;
try
{
fin1 = new FileInputStream(srcFilePathName);
fout1 = new FileOutputStream(targetFilePathName);
FileChannel fcin = fin1.getChannel();
FileChannel fcout = fout1.getChannel();
int fileLength = (int) fcin.size();
start = System.currentTimeMillis();
fcin.transferTo(0, fileLength, fcout);
}
catch (FileNotFoundException e)
{
e.printStackTrace();
}
catch (IOException e)
{
e.printStackTrace();
}
finally
{
try
{
fin1.close();
fout1.close();
}
catch (IOException e)
{
e.printStackTrace();
}
}
long end = System.currentTimeMillis();
long time1 = end - start;
System.out.println("NIO_time1: " + time1);
/** 通过NIO实现文件读写方式2 */
FileInputStream fin11 = null;
FileOutputStream fout11 = null;
try
{
fin11 = new FileInputStream(srcFilePathName);
fout11 = new FileOutputStream(targetFilePathName);
FileChannel fcin11 = fin11.getChannel();
FileChannel fcout11 = fout11.getChannel();
ByteBuffer buffer = ByteBuffer.allocate(512);
start = System.currentTimeMillis();
while (fcin11.read(buffer) != -1)
{
buffer.flip();
fcout11.write(buffer);
/** 从缓冲区写入数据之后调用此方法,以防写入不完整 */
buffer.compact();
buffer.clear();
}
}
catch (FileNotFoundException e)
{
e.printStackTrace();
}
catch (IOException e)
{
e.printStackTrace();
}
finally
{
try
{
fin11.close();
fout11.close();
}
catch (IOException e)
{
e.printStackTrace();
}
}
end = System.currentTimeMillis();
long time11 = end - start;
System.out.println("NIO_time2: " + time11);
}
}
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