增加读处理handler

src/main/java/com/paul0523/ReadHandler.java

+package com.paul0523;
+
+import java.nio.ByteBuffer;
+import java.nio.channels.SelectionKey;
+import java.nio.channels.Selector;
+import java.nio.channels.SocketChannel;
+import java.nio.charset.Charset;
+
+public class ReadHandler implements Runnable{
+
+    private SelectionKey selectionKey;
+
+    public ReadHandler(SelectionKey selectionKey) {
+        this.selectionKey = selectionKey;
+    }
+
+    @Override
+    public void run() {
+        try {
+            SocketChannel socketChannel = (SocketChannel) selectionKey.channel();
+            ByteBuffer byteBuffer = (ByteBuffer) selectionKey.attachment();
+            byteBuffer.clear();
+            int readbytes = socketChannel.read(byteBuffer);
+            byteBuffer.flip();
+            if (readbytes > 0) {
+                byte[] bytes = new byte[readbytes];
+                byteBuffer.get(bytes, 0, readbytes);
+                System.out.println(new String(bytes, 0, readbytes, Charset.forName("utf-8")));
+            } else if (readbytes == -1) {
+                socketChannel.close();
+                return;
+            }
+            byteBuffer.flip();
+            selectionKey.attach(byteBuffer);
+            selectionKey.interestOps(SelectionKey.OP_WRITE | SelectionKey.OP_READ);
+            selectionKey.selector().wakeup();
+        } catch (Exception e) {
+            e.printStackTrace();
+        }
+
+    }
+}