GatheringByteChannel
写入多个通道 − 在此中，我们将来自多个缓冲区的数据写入单个通道。为此，将再次分配多个缓冲区并将其添加到缓冲区类型数组中。然后，此数组作为参数传递给 GatheringByteChannel write() 方法，该方法然后按照缓冲区在数组中出现的顺序从多个缓冲区写入数据。这里要记住的一点是只写入缓冲区的位置和极限之间的数据。
以下示例显示了如何在 Java NIO 中执行数据收集
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.channels.GatheringByteChannel;
public class GatherExample {
private static String FILENAME = "C:/Test/temp.txt";
public static void main(String[] args) {
String stream1 = "Gather data stream first";
String stream2 = "Gather data stream second";
ByteBuffer bLen1 = ByteBuffer.allocate(1024);
ByteBuffer bLen2 = ByteBuffer.allocate(1024);
// Next two buffer hold the data we want to write
ByteBuffer bstream1 = ByteBuffer.wrap(stream1.getBytes());
ByteBuffer bstream2 = ByteBuffer.wrap(stream2.getBytes());
int len1 = stream1.length();
int len2 = stream2.length();
// Writing length(data) to the Buffer
bLen1.asIntBuffer().put(len1);
bLen2.asIntBuffer().put(len2);
System.out.println("Gathering : Len1 = " + len1);
System.out.println("Gathering : Len2 = " + len2);
// Write data to the file
try {
FileOutputStream out = new FileOutputStream(FILENAME);
GatheringByteChannel gather = out.getChannel();
gather.write(new ByteBuffer[] {bLen1, bLen2, bstream1, bstream2});
out.close();
gather.close();
}
catch (FileNotFoundException exObj) {
exObj.printStackTrace();
}
catch(IOException ioObj) {
ioObj.printStackTrace();
}
}
}
