Jedis源碼解析——Jedis和BinaryJedis

1、基本信息

先來看看他們的類定義：

public class Jedis extends BinaryJedis implements 

JedisCommands, MultiKeyCommands,
    AdvancedJedisCommands, ScriptingCommands, BasicCommands, ClusterCommands, SentinelCommands {
    ……
    }

public class BinaryJedis implements 

BasicCommands, BinaryJedisCommands, MultiKeyBinaryCommands,
    AdvancedBinaryJedisCommands, BinaryScriptingCommands, Closeable {
    ……
    }

Jedis繼承自BinaryJedis，二者都實現了一系列的命令接口。

仔細看就能發現，這些接口幾乎是一一對應的：例如MultiKeyBinaryCommands和MultiKeyCommands，BinaryScriptingCommands和ScriptingCommands等等。從名字就可以看出來他們之間的區別就是是否是binary（二進制）的，從他們的各自的方法中可以找到依據。

public interface MultiKeyBinaryCommands {
  Long del(byte[]... keys);

  List<byte[]> blpop(int timeout, byte[]... keys);

  List<byte[]> brpop(int timeout, byte[]... keys);

  List<byte[]> blpop(byte[]... args);

  List<byte[]> brpop(byte[]... args);

  Set<byte[]> keys(byte[] pattern);
  ……

}

public interface MultiKeyCommands {
  Long del(String... keys);

  List<String> blpop(int timeout, String... keys);

  List<String> brpop(int timeout, String... keys);

  List<String> blpop(String... args);

  List<String> brpop(String... args);

  Set<String> keys(String pattern);

……

}

這些接口命令中，只有BasicCommands是相同的，不存在是不是二進制相關的方法。因爲該類中主要是redis的其他操作，並不涉及具體數據類型的操作。簡單看幾個方法就知道了。

public interface BasicCommands {

  String ping();

  String quit();

  String flushDB();

  Long dbSize();

  String select(int index);

  String flushAll();

  String auth(String password);
……
}

2、結構關係

前面介紹完了兩個類之間的關係和實現的接口，雖然我們平常使用以jedis居多，但其實精華都在binaryJedis中。

//真正的客戶端
 protected Client client = null;
 //用來區分是否是事務操作
  protected Transaction transaction = null;
  protected Pipeline pipeline = null;

//下面列舉了幾種比較典型的構造方法

  public BinaryJedis() {
    client = new Client();
  }

  public BinaryJedis(final String host) {
    URI uri = URI.create(host);
    if (uri.getScheme() != null && uri.getScheme().equals("redis")) {
      initializeClientFromURI(uri);
    } else {
      client = new Client(host);
    }
  }


  public BinaryJedis(final String host, final int port, final int connectionTimeout,
      final int soTimeout) {
    client = new Client(host, port);
    client.setConnectionTimeout(connectionTimeout);
    client.setSoTimeout(soTimeout);
  }

  public BinaryJedis(final JedisShardInfo shardInfo) {
    client = new Client(shardInfo.getHost(), shardInfo.getPort());
    client.setConnectionTimeout(shardInfo.getConnectionTimeout());
    client.setSoTimeout(shardInfo.getSoTimeout());
    client.setPassword(shardInfo.getPassword());
    client.setDb(shardInfo.getDb());
  }


  public BinaryJedis(final URI uri, final int timeout) {
    initializeClientFromURI(uri);
    client.setConnectionTimeout(timeout);
    client.setSoTimeout(timeout);
  }

構造函數中的操作，基本上都是創建Client，並初始化數據信息。那麼這個Client是個什麼呢？

public class Client extends BinaryClient implements Commands {}

public class BinaryClient extends Connection {}

Tips:Client與BinaryClient的區別：BinaryClient是原生客戶端，而Client封裝性更好，也被叫做高級客戶端。

Connection類中主要是socket進行通信，一個Connection已經就是一個最基礎的客戶端。

另外增加各種協議層次的發送命令和收取結果的方法，都是通過Protocol類的操作RedisOutputStream和RedisInputStream完成的。封裝了輸入輸出流，來方便使用。

public class Connection implements Closeable {

  private String host = Protocol.DEFAULT_HOST;
  private int port = Protocol.DEFAULT_PORT;
  private Socket socket;
  private RedisOutputStream outputStream;
  private RedisInputStream inputStream;
  ……
  }

主要方法：

1、connect()

 public void connect() {
    if (!isConnected()) {
      try {
      //創建socket，設置相關參數
        socket = new Socket();
        socket.setReuseAddress(true);
        socket.setKeepAlive(true); // Will monitor the TCP connection is
        // valid
        socket.setTcpNoDelay(true); // Socket buffer Whetherclosed, to
        // ensure timely delivery of data
        socket.setSoLinger(true, 0); // Control calls close () method,
        // 連接
        socket.connect(new InetSocketAddress(host, port), connectionTimeout);
        socket.setSoTimeout(soTimeout);
        //輸入輸出
        outputStream = new RedisOutputStream(socket.getOutputStream());
        inputStream = new RedisInputStream(socket.getInputStream());
      } catch (IOException ex) {
        broken = true;
        throw new JedisConnectionException(ex);
      }
    }
  }

2、disconnect()

public void disconnect() {
    if (isConnected()) {
      try {
        outputStream.flush();
        socket.close();
      } catch (IOException ex) {
        broken = true;
        throw new JedisConnectionException(ex);
      } finally {
        IOUtils.closeQuietly(socket);
      }
    }
  }

3、isConnected()

  public boolean isConnected() {
    return socket != null && socket.isBound() && !socket.isClosed() && socket.isConnected()
        && !socket.isInputShutdown() && !socket.isOutputShutdown();
  }