根据 Redis 的 RESP 协议，我们可以看出，SOCKET 在给 Redis 服务器发送数据需要遵循如下格式：

  1. *3
  2. $3
  3. SET
  4. $4
  5. test
  6. $6
  7. 123456

那么我们可以利用 SOCKET 来自己实现一套 Redis 客户端

RESP 协议类

  1. public class Resp {
  3.     public static final String START = "*";
  5.     public static final String STR_LENGTH = "$";
  7.     public static final String LINE = "\r\n";
  9.     public enum command {
  10.         SET, GET, INCR
  11.     }
  13. }

RedisClient Socket

  1. public class MyJedisSocket {
  3.     private Socket socket;
  4.     private InputStream inputStream;
  5.     private OutputStream outputStream;
  7.     public MyJedisSocket(String host, int port) {
  8.         try {
  9.             socket = new Socket(host, port);
  10.             inputStream = socket.getInputStream();
  11.             outputStream = socket.getOutputStream();
  12.         } catch (IOException e) {
  13.             e.printStackTrace();
  14.         }
  15.     }
  17.     // 向 Redis 服务器发送数据
  18.     public void send(String str) {
  19.         try {
  20.             outputStream.write(str.getBytes());
  21.         } catch (IOException e) {
  22.             e.printStackTrace();
  23.         }
  24.     }
  26.     // 读取 Redis 服务器端返回的数据
  27.     public String read() {
  28.         byte[] buffer = new byte[1024];
  29.         int count = 0;
  30.         try {
  31.             count = inputStream.read(buffer);
  32.         } catch (IOException e) {
  33.             e.printStackTrace();
  34.         }
  35.         return new String(buffer, 0, count, StandardCharsets.UTF_8);
  36.     }
  37. }

Redis Client 类

  1. public class MyJedis {
  3.     private MyJedisSocket myJedisSocket;
  5.     public MyJedis(String host, int port) {
  6.         myJedisSocket = new MyJedisSocket(host, port);
  7.     }
  9.     public String set(String key, String value) {
  10.         myJedisSocket.send(covert(Resp.command.SET, key, value));
  11.         return myJedisSocket.read();
  12.     }
  14.     public String get(String key) {
  15.         myJedisSocket.send(covert(Resp.command.GET, key));
  16.         return myJedisSocket.read();
  17.     }
  19.     public String incr(String key) {
  20.         myJedisSocket.send(covert(Resp.command.INCR, key));
  21.         return myJedisSocket.read();
  22.     }
  24.     public static String covert(Resp.command command, String... strings) {
  25.         StringBuilder sb = new StringBuilder();
  26.         sb.append(Resp.START).append(1 + strings.length).append(Resp.LINE);
  27.         sb.append(Resp.STR_LENGTH).append(command.toString().length()).append(Resp.LINE);
  28.         sb.append(command.name()).append(Resp.LINE);
  30.         for (String str : strings) {
  31.             sb.append(Resp.STR_LENGTH).append(str.length()).append(Resp.LINE);
  32.             sb.append(str).append(Resp.LINE);
  33.         }
  34.         return sb.toString();
  35.     }
  37.     public static void main(String[] args) {
  38.         MyJedis jedis = new MyJedis("127.0.0.1", 6379);
  39.         System.out.println(jedis.set("test", "123456"));
  40.         System.out.println(jedis.get("test"));
  41.         System.out.println(jedis.incr("lock"));
  42.     }
  44. }