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本篇内容主要讲解“如何测试FileChannel结合MappedByteBuffer往文件中写入数据”，感兴趣的朋友不妨来看看。本文介绍的方法操作简单快捷，实用性强。下面就让小编来带大家学习“如何测试FileChannel结合MappedByteBuffer往文件中写入数据”吧!
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FileChannel结合ByteBuffer测试
package com;
import java.io.RandomAccessFile;
import java.nio.ByteBuffer;
import java.nio.channels.FileChannel;
/**
* FileChannel Test
*
* @author Dale
* @date 2019/10/23
*/
public class FileChannelTest{
static ByteBuffer writeBuffer = ByteBuffer.allocate(9);
static Integer wrotePosition = 0;
static Integer committedPosition = 0;
static FileChannel fileChannel = null;
static {
try {
RandomAccessFile randomAccessFile = new RandomAccessFile("d://test.log", "rw");
fileChannel = randomAccessFile.getChannel();
}catch (Exception e){
e.printStackTrace();
}
}
public static void main(String[] args) throws Exception{
appendData("1234");
commit();
appendData("567");
commit();
appendData("89");
commit();
//fileChannel.force(false);
}
public static void appendData(String msg) throws Exception{
int msgLen = msg.length();
ByteBuffer byteBuffer = writeBuffer.slice();
byteBuffer.position(wrotePosition);
ByteBuffer msgStoreItemMemory = ByteBuffer.allocate(msgLen);
msgStoreItemMemory.put(msg.getBytes("UTF-8"));
byteBuffer.put(msgStoreItemMemory.array(), 0, msgLen);
wrotePosition = wrotePosition + msgLen;
}
public static void commit() throws Exception{
ByteBuffer byteBuffer = writeBuffer.slice();
byteBuffer.position(committedPosition);
byteBuffer.limit(wrotePosition);
fileChannel.position(committedPosition);
fileChannel.write(byteBuffer);
committedPosition = wrotePosition;
}
}MappedByteBuffer结合ByteBuffer测试
package com;
import java.io.RandomAccessFile;
import java.nio.ByteBuffer;
import java.nio.MappedByteBuffer;
import java.nio.channels.FileChannel;
/**
* MappedByteBuffer Test
*
* @author Dale
* @date 2019/10/23
*/
public class MappedByteBufferTest {
static ByteBuffer writeBuffer = ByteBuffer.allocate(9);
static Integer wrotePosition = 0;
static Integer committedPosition = 0;
static FileChannel fileChannel = null;
static MappedByteBuffer mappedByteBuffer;
static {
try {
RandomAccessFile randomAccessFile = new RandomAccessFile("d://test.log", "rw");
fileChannel = randomAccessFile.getChannel();
mappedByteBuffer = fileChannel.map(FileChannel.MapMode.READ_WRITE, 0, 9);
}catch (Exception e){
e.printStackTrace();
}
}
public static void main(String[] args) throws Exception{
appendData("1234");
appendData("567");
appendData("89");
//mappedByteBuffer.force();
}
public static void appendData(String msg) throws Exception{
int msgLen = msg.length();
ByteBuffer byteBuffer = mappedByteBuffer.slice();
byteBuffer.position(wrotePosition);
ByteBuffer msgStoreItemMemory = ByteBuffer.allocate(msgLen);
msgStoreItemMemory.put(msg.getBytes("UTF-8"));
byteBuffer.put(msgStoreItemMemory.array(), 0, msgLen);
wrotePosition = wrotePosition + msgLen;
}
}到此，相信大家对“如何测试FileChannel结合MappedByteBuffer往文件中写入数据”有了更深的了解，不妨来实际操作一番吧！这里是创新互联网站，更多相关内容可以进入相关频道进行查询，关注我们，继续学习！
