netty案例，netty4.1源码分析篇四《ByteBuf的数据结构在使用方式中的剖析》
最编程
2024-01-14 12:52:34
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// 62 75 67 73 74 61 63 6B B3 E6 B6 B4 D5 BB
public static void main(String[] args) throws UnsupportedEncodingException {
// 1.创建一个非池化的ByteBuf，大小为14个字节
ByteBuf buffer = Unpooled.buffer(14);
System.out.println("1.创建一个非池化的ByteBuf，大小为14个字节");
System.out.println("ByteBuf空间大小：" + buffer.capacity());
// 2.写入3个字节
buffer.writeByte(62);
buffer.writeByte(75);
buffer.writeByte(67);
System.out.println("\r\n2.写入3个字节");
System.out.println("readerIndex位置：" + buffer.readerIndex());
System.out.println("writerIndex位置：" + buffer.writerIndex());
// 3.写入一段字节
byte[] bytes = {73, 74, 61, 63, 0x6B};
buffer.writeBytes(bytes);
System.out.println("\r\n3.写入一段字节");
System.out.println("readerIndex位置：" + buffer.readerIndex());
System.out.println("writerIndex位置：" + buffer.writerIndex());
// 4.读取全部内容
byte[] allBytes = new byte[buffer.readableBytes()];
buffer.readBytes(allBytes);
System.out.println("\r\n4.读取全部内容");
System.out.println("readerIndex位置：" + buffer.readerIndex());
System.out.println("writerIndex位置：" + buffer.writerIndex());
System.out.println("读取全部内容：" + Arrays.toString(allBytes));
// 5.重置指针位置
buffer.resetReaderIndex();
System.out.println("\r\n5.重置指针位置");
System.out.println("readerIndex位置：" + buffer.readerIndex());
System.out.println("writerIndex位置：" + buffer.writerIndex());
// 6.读取3个字节
byte b0 = buffer.readByte();
byte b1 = buffer.readByte();
byte b2 = buffer.readByte();
System.out.println("\r\n6.读取3个字节");
System.out.println("readerIndex位置：" + buffer.readerIndex());
System.out.println("writerIndex位置：" + buffer.writerIndex());
System.out.println("读取3个字节：" + Arrays.toString(new byte[]{b0, b1, b2}));
// 7.读取一段字节
ByteBuf byteBuf = buffer.readBytes(5);
byte[] dst = new byte[5];
byteBuf.readBytes(dst);
System.out.println("\r\n7.读取一段字节");
System.out.println("readerIndex位置：" + buffer.readerIndex());
System.out.println("writerIndex位置：" + buffer.writerIndex());
System.out.println("读取一段字节：" + Arrays.toString(dst));
// 8.丢弃已读内容
buffer.discardReadBytes();
System.out.println("\r\n8.丢弃已读内容");
System.out.println("readerIndex位置：" + buffer.readerIndex());
System.out.println("writerIndex位置：" + buffer.writerIndex());
// 9.清空指针位置
buffer.clear();
System.out.println("\r\n9.清空指针位置");
System.out.println("readerIndex位置：" + buffer.readerIndex());
System.out.println("writerIndex位置：" + buffer.writerIndex());
// 10.ByteBuf中还有很多其他方法；拷贝、标记、跳过字节，多用于自定义解码器进行半包粘包处理
}