Netty learning 11- ByteBuffer buffer [1]

Code Example 1

import java.nio.ByteBuffer;
public class JDKByteBufferTest {
	public static void main(String[] args) {
		// 初始化ByteBuffer
		ByteBuffer buffer = ByteBuffer.allocate(20);
		System.out.println(String.format(
				"##### position:%s limit:%s remaining:%s", buffer.position(),
				buffer.limit(), buffer.remaining()));

		// put操作
		String msg = "xy";
		buffer.put(msg.getBytes());
		System.out.println(String.format(
				"##### position:%s limit:%s remaining:%s", buffer.position(),
				buffer.limit(), buffer.remaining()));

		// flip操作
		buffer.flip();
		System.out.println(String.format(
				"##### position:%s limit:%s remaining:%s", buffer.position(),
				buffer.limit(), buffer.remaining()));

		// 获取值，读取的内容从position->limit
		byte[] array = new byte[buffer.remaining()];
		buffer.get(array);
		String result = new String(array);
		System.out.println("result is " + result);
		System.out.println(String.format(
				"##### position:%s limit:%s remaining:%s", buffer.position(),
				buffer.limit(), buffer.remaining()));
	}
}

##### position:0 limit:20 remaining:20
##### position:2 limit:20 remaining:18
##### position:0 limit:2 remaining:2
result is xy
##### position:2 limit:2 remaining:0

2 icon

3 JDK ByteBuffer limitations

[1] fixed length . Upon completion of task assignment, its capacity can not be dynamically expanded or contracted, when an object to be encoded is greater than ByteBuffer POJO capacity index bounds exception occurs.
[2] identifies the location of only one pointer position . Literacy is the need to manually flip and rewind, etc., need to be very careful with these API, it will easily lead to abnormal.
[3] limited API function . Does not support the use of some advanced features require the user to achieve.