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java | 非阻塞模式

发表于 更新于 分类于 ， ， ， ， Valine：

非阻塞模式。

引入自写的方法类。

下载 JAVA 文件

netty 包

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<dependency>
    <groupId>io.netty</groupId>
    <artifactId>netty-all</artifactId>
    <version>4.1.86.Final</version>
</dependency>

服务端代码

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package com.redisc;

import lombok.extern.slf4j.Slf4j;

import java.io.IOException;
import java.net.InetSocketAddress;
import java.nio.ByteBuffer;
import java.nio.channels.ServerSocketChannel;
import java.nio.channels.SocketChannel;
import java.util.ArrayList;
import java.util.List;

import static com.redisc.ByteBufferUtil.debugRead;

@Slf4j(topic = "c.Test")
public class Run {

    public static void main(String[] args) throws IOException {
        // 使用 nio 单线程
        // bytebuffer
        ByteBuffer buffer = ByteBuffer.allocate(16);
        // 创建服务器
        ServerSocketChannel ssc = ServerSocketChannel.open();
        ssc.configureBlocking(false);//将阻塞模式切换为非阻塞模式
        //绑定端口
        ssc.bind(new InetSocketAddress(8090));
        //连接集合
        List<SocketChannel> channelList = new ArrayList<>();
        while (true) {
            // accept 建立客户断连接，SocketChannel 用来与客户端通信
            SocketChannel sc = ssc.accept(); // accept 是一个非阻塞方法，线程还会继续运行，如果没有连接，sc 是 null
            if (sc != null) {
                sc.configureBlocking(false);// 设置sc为非阻塞模式
                channelList.add(sc);

            }
            for (SocketChannel channel : channelList) {
                // 接收客户端发送的数据
                int read = channel.read(buffer); // 非阻塞方法，如果没有读到数据 read 返回 0
                if (read > 0) {
                    buffer.flip();
                    debugRead(buffer);
                    buffer.clear();
                    log.debug("after read...{}", channel);
                }
            }
        }
    }

}

客户端代码

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package com.redisc;

import java.io.IOException;
import java.net.InetSocketAddress;
import java.nio.channels.SocketChannel;

public class Client {
    public static void main(String[] args) throws IOException {
        SocketChannel sc = SocketChannel.open();
        sc.connect(new InetSocketAddress("localhost", 8090));
        System.out.println("waiting...");
    }
}

验证

开启服务器。

客户端代码，在 11 行打断点。开启客户端，在 sc 变量上执行

多次执行

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sc.write(Charset.defaultCharset().encode("hi"))

输出

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15:42:49.416 [main] DEBUG io.netty.util.internal.logging.InternalLoggerFactory - Using SLF4J as the default logging framework
+--------+-------------------- read -----------------------+----------------+
position: [0], limit: [2]
         +-------------------------------------------------+
         |  0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f |
+--------+-------------------------------------------------+----------------+
|00000000| 68 69                                           |hi              |
+--------+-------------------------------------------------+----------------+
15:42:49.470 [main] DEBUG c.Test - after read...java.nio.channels.SocketChannel[connected local=/127.0.0.1:8090 remote=/127.0.0.1:53153]
+--------+-------------------- read -----------------------+----------------+
position: [0], limit: [2]
         +-------------------------------------------------+
         |  0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f |
+--------+-------------------------------------------------+----------------+
|00000000| 68 69                                           |hi              |
+--------+-------------------------------------------------+----------------+
15:42:52.402 [main] DEBUG c.Test - after read...java.nio.channels.SocketChannel[connected local=/127.0.0.1:8090 remote=/127.0.0.1:53153]
+--------+-------------------- read -----------------------+----------------+
position: [0], limit: [2]
         +-------------------------------------------------+
         |  0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f |
+--------+-------------------------------------------------+----------------+
|00000000| 68 69                                           |hi              |
+--------+-------------------------------------------------+----------------+
15:42:53.171 [main] DEBUG c.Test - after read...java.nio.channels.SocketChannel[connected local=/127.0.0.1:8090 remote=/127.0.0.1:53153]
+--------+-------------------- read -----------------------+----------------+
position: [0], limit: [2]
         +-------------------------------------------------+
         |  0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f |
+--------+-------------------------------------------------+----------------+
|00000000| 68 69                                           |hi              |
+--------+-------------------------------------------------+----------------+
15:42:53.767 [main] DEBUG c.Test - after read...java.nio.channels.SocketChannel[connected local=/127.0.0.1:8090 remote=/127.0.0.1:53153]
+--------+-------------------- read -----------------------+----------------+
position: [0], limit: [2]
         +-------------------------------------------------+
         |  0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f |
+--------+-------------------------------------------------+----------------+
|00000000| 68 69                                           |hi              |
+--------+-------------------------------------------------+----------------+
15:42:54.375 [main] DEBUG c.Test - after read...java.nio.channels.SocketChannel[connected local=/127.0.0.1:8090 remote=/127.0.0.1:53153]

但是这样会导致，cpu 利用率一直是 100%。

请我喝杯咖啡吧～