[add] add GatherTest for nio

Author: brianway

java-io/src/test/java/com/brianway/java/nio/tutorial/GatherTest.java

@@ -0,0 +1,37 @@
+package com.brianway.java.nio.tutorial;
+
+import com.brianway.learning.java.nio.tutorial.BufferDemo;
+import org.junit.Test;
+
+import java.io.IOException;
+import java.io.RandomAccessFile;
+import java.nio.ByteBuffer;
+import java.nio.channels.FileChannel;
+import java.nio.charset.Charset;
+
+/**
+ * @auther brian
+ * @since 2019/6/18 23:51
+ */
+public class GatherTest {
+
+ private String path = BufferDemo.class.getResource("/").getPath() + "gather.txt";
+
+ @Test
+ public void testGatheringWrites() throws IOException {
+ RandomAccessFile aFile = new RandomAccessFile(path, "rw");
+ FileChannel channel = aFile.getChannel();
+ ByteBuffer header = ByteBuffer.allocate(128);
+ ByteBuffer body = ByteBuffer.allocate(1024);
+
+ header.put("这是头".getBytes(Charset.forName("UTF-8")));
+ body.put("this is body.".getBytes(Charset.forName("UTF-8")));
+ header.flip();
+ body.flip();
+ //write data into buffers
+ ByteBuffer[] bufferArray = {header, body};
+ // 注意只有position和limit之间的数据才会被写入
+ channel.write(bufferArray);
+ channel.close();
+ }
+}