jdeis 分析

• 入口代码

  JedisPool pool = new JedisPool(new JedisPoolConfig(), hnp.getHost(), hnp.getPort(), 2000);

  逐步跟进会初始化一个JedisFactory通过构造方法把后面需要的值提前赋值:
  public JedisPool(final GenericObjectPoolConfig poolConfig, final String host, int port,
    final int connectionTimeout, final int soTimeout, final String password, final int database,
    final String clientName) {
  super(poolConfig, new JedisFactory(host, port, connectionTimeout, soTimeout, password,
      database, clientName));
  }
  
  继续深入点入会初始化连接池:
  public void initPool(final GenericObjectPoolConfig poolConfig, PooledObjectFactory<T> factory) {
  
  if (this.internalPool != null) {
    try {
      closeInternalPool();
    } catch (Exception e) {
    }
  }
  
  this.internalPool = new GenericObjectPool<T>(factory, poolConfig);
  }

• 关于GenericObjectPool

  GenericObjectPool是apache提供的对象池，需要的参数是PooledObjectFactory，jedis中传入JedisFactory，
  有很多作用，比如连接池中没有对象时，可以调用makeObject方法创建一个连接对象
  GenericObjectPool的构造方法:
  this.idleObjects = new LinkedBlockingDeque(config.getFairness());  初始化一个队列存放连接
  获取池中的对象是通过GenericObjectPool的borrowObject()方法

• 回到jedis获取连接

  Jedis jedis = pool.getResource(); 获取一个jedis
  getResource:
  return internalPool.borrowObject();   对应上面的GenericObjectPool
  
  public T borrowObject() throws Exception {
      return this.borrowObject(this.getMaxWaitMillis());//最大等待时间
  }
  
  没有连接的时候会去创建:
  p = (PooledObject)this.idleObjects.pollFirst();
                      if (p == null) {
                          p = this.create();//会执行JedisFactory.makeObject方法，创建socket
                          if (p != null) {
                              create = true;
                          }
  }
  
  validate = this.factory.validateObject(p);判断连接是否可用   (通过发送ping命令)

• JedisFactory.makeObject 方法分析

  public PooledObject<Jedis> makeObject() throws Exception {
  final HostAndPort hostAndPort = this.hostAndPort.get();
  final Jedis jedis = new Jedis(hostAndPort.getHost(), hostAndPort.getPort(), connectionTimeout,
      soTimeout, ssl, sslSocketFactory, sslParameters, hostnameVerifier);
  
  try {
    jedis.connect();
    if (password != null) {
      jedis.auth(password);
    }
    if (database != 0) {
      jedis.select(database);
    }
    if (clientName != null) {
      jedis.clientSetname(clientName);
    }
  } catch (JedisException je) {
    jedis.close();
    throw je;
  }
  
  return new DefaultPooledObject<Jedis>(jedis);
  
  }
  构造BinaryJedis    （BinaryClient extends Connection）
  public BinaryJedis(final String host, final int port, final int connectionTimeout,
    final int soTimeout, final boolean ssl, final SSLSocketFactory sslSocketFactory,
    final SSLParameters sslParameters, final HostnameVerifier hostnameVerifier) {
  client = new Client(host, port, ssl, sslSocketFactory, sslParameters, hostnameVerifier);
  client.setConnectionTimeout(connectionTimeout);
  client.setSoTimeout(soTimeout);
  }
  
  创建连接:
  public void connect() {
  if (!isConnected()) {
    super.connect();
    if (password != null) {
      auth(password);
      getStatusCodeReply();
    }
    if (db > 0) {
      select(db);
      getStatusCodeReply();
    }
  }
  }
  
  Connection中的connect方法:
  public void connect() {
  if (!isConnected()) {
    try {
      socket = new Socket();
      // ->@wjw_add
      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,
      // the underlying socket is closed
      // immediately
      // <-@wjw_add
  
      socket.connect(new InetSocketAddress(host, port), connectionTimeout);
      socket.setSoTimeout(soTimeout);
  
      if (ssl) {
        if (null == sslSocketFactory) {
          sslSocketFactory = (SSLSocketFactory)SSLSocketFactory.getDefault();
        }
        socket = sslSocketFactory.createSocket(socket, host, port, true);
        if (null != sslParameters) {
          ((SSLSocket) socket).setSSLParameters(sslParameters);
        }
        if ((null != hostnameVerifier) &&
            (!hostnameVerifier.verify(host, ((SSLSocket) socket).getSession()))) {
          String message = String.format(
              "The connection to '%s' failed ssl/tls hostname verification.", host);
          throw new JedisConnectionException(message);
        }
      }
  
      outputStream = new RedisOutputStream(socket.getOutputStream());
      inputStream = new RedisInputStream(socket.getInputStream());
    } catch (IOException ex) {
      broken = true;
      throw new JedisConnectionException("Failed connecting to host " 
          + host + ":" + port, ex);
    }
  }
  }
  
  具体执行命令:
  jedis.set("foo", "bar");
  public String set(final String key, final String value) {
  checkIsInMultiOrPipeline();
  client.set(key, value);
  return client.getStatusCodeReply();
  }
  connect();
  Protocol.sendCommand(outputStream, cmd, args);

• 归还连接到池子

  jedis.close();
  pool.destroy(); 
  internalPool.returnObject(resource);  归还资源到连接池

简单来说jedis整个交互过程是一个Socket通信过程。