37 lines
1.3 KiB
Java
37 lines
1.3 KiB
Java
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package com.cowr.common.netty;
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import com.alibaba.fastjson.JSON;
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import io.netty.buffer.ByteBuf;
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import io.netty.channel.ChannelHandlerContext;
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import io.netty.handler.codec.ByteToMessageDecoder;
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import java.util.List;
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public class JSONDecoder extends ByteToMessageDecoder {
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//目标对象类型进行解码
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private Class<?> target;
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public JSONDecoder(Class target) {
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this.target = target;
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}
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@Override
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protected void decode(ChannelHandlerContext ctx, ByteBuf in, List<Object> out) throws Exception {
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if (in.readableBytes() < 4) { //不够长度丢弃
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return;
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}
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in.markReaderIndex(); //标记一下当前的readIndex的位置
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int dataLength = in.readInt(); // 读取传送过来的消息的长度。ByteBuf 的readInt()方法会让他的readIndex增加4
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if (in.readableBytes() < dataLength) { //读到的消息体长度如果小于我们传送过来的消息长度，则resetReaderIndex. 这个配合markReaderIndex使用的。把readIndex重置到mark的地方
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in.resetReaderIndex();
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return;
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}
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byte[] data = new byte[dataLength];
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in.readBytes(data);
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Object obj = JSON.parseObject(data, target); //将byte数据转化为我们需要的对象
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out.add(obj);
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}
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}
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