Jedis 源代码阅读一 —— Jedis

Posted 2020-10-03 llguanli

这是jedis 源代码文件夹，我们接下来选择性阅读重要的接口以及实现。

└─redis
    └─clients
        ├─jedis
        │  │  BinaryClient.java
        │  │  BinaryJedis.java
        │  │  BinaryJedisCluster.java
        │  │  BinaryJedisPubSub.java
        │  │  BinaryShardedJedis.java
        │  │  BitOP.java
        │  │  BitPosParams.java
        │  │  Builder.java
        │  │  BuilderFactory.java
        │  │  Client.java
        │  │  Connection.java
        │  │  DebugParams.java
        │  │  GeoCoordinate.java
        │  │  GeoRadiusResponse.java
        │  │  GeoUnit.java
        │  │  HostAndPort.java
        │  │  Jedis.java
        │  │  JedisCluster.java
        │  │  JedisClusterCommand.java
        │  │  JedisClusterConnectionHandler.java
        │  │  JedisClusterInfoCache.java
        │  │  JedisFactory.java
        │  │  JedisMonitor.java
        │  │  JedisPool.java
        │  │  JedisPoolAbstract.java
        │  │  JedisPoolConfig.java
        │  │  JedisPubSub.java
        │  │  JedisSentinelPool.java
        │  │  JedisShardInfo.java
        │  │  JedisSlotBasedConnectionHandler.java
        │  │  MultiKeyPipelineBase.java
        │  │  Pipeline.java
        │  │  PipelineBase.java
        │  │  Protocol.java
        │  │  Queable.java
        │  │  Response.java
        │  │  ScanParams.java
        │  │  ScanResult.java
        │  │  ShardedJedis.java
        │  │  ShardedJedisPipeline.java
        │  │  ShardedJedisPool.java
        │  │  SortingParams.java
        │  │  Transaction.java
        │  │  Tuple.java
        │  │  ZParams.java
        │  │  
        │  ├─commands
        │  │      AdvancedBinaryJedisCommands.java
        │  │      AdvancedJedisCommands.java
        │  │      BasicCommands.java
        │  │      BasicRedisPipeline.java
        │  │      BinaryJedisClusterCommands.java
        │  │      BinaryJedisCommands.java
        │  │      BinaryRedisPipeline.java
        │  │      BinaryScriptingCommands.java
        │  │      BinaryScriptingCommandsPipeline.java
        │  │      ClusterCommands.java
        │  │      ClusterPipeline.java
        │  │      Commands.java
        │  │      JedisClusterBinaryScriptingCommands.java
        │  │      JedisClusterCommands.java
        │  │      JedisClusterScriptingCommands.java
        │  │      JedisCommands.java
        │  │      MultiKeyBinaryCommands.java
        │  │      MultiKeyBinaryJedisClusterCommands.java
        │  │      MultiKeyBinaryRedisPipeline.java
        │  │      MultiKeyCommands.java
        │  │      MultiKeyCommandsPipeline.java
        │  │      MultiKeyJedisClusterCommands.java
        │  │      ProtocolCommand.java
        │  │      RedisPipeline.java
        │  │      ScriptingCommands.java
        │  │      ScriptingCommandsPipeline.java
        │  │      SentinelCommands.java
        │  │      
        │  ├─exceptions
        │  │      InvalidURIException.java
        │  │      JedisAskDataException.java
        │  │      JedisClusterCrossSlotException.java
        │  │      JedisClusterException.java
        │  │      JedisClusterMaxRedirectionsException.java
        │  │      JedisConnectionException.java
        │  │      JedisDataException.java
        │  │      JedisException.java
        │  │      JedisMovedDataException.java
        │  │      JedisRedirectionException.java
        │  │      
        │  └─params
        │      │  Params.java
        │      │  
        │      ├─geo
        │      │      GeoRadiusParam.java
        │      │      
        │      ├─set
        │      │      SetParams.java
        │      │      
        │      └─sortedset
        │              ZAddParams.java
        │              ZIncrByParams.java
        │              
        └─util
                ClusterNodeInformation.java
                ClusterNodeInformationParser.java
                Hashing.java
                IOUtils.java
                JedisByteHashMap.java
                JedisClusterCRC16.java
                JedisURIHelper.java
                KeyMergeUtil.java
                MurmurHash.java
                Pool.java
                RedisInputStream.java
                RedisOutputStream.java
                SafeEncoder.java
                Sharded.java
                ShardInfo.java
                Slowlog.java

Jedis.java

我们每次使用jedis都会初始化一个jedis对象，对下面代码肯定不会陌生：

public class Jedis extends BinaryJedis implements JedisCommands, MultiKeyCommands,
    AdvancedJedisCommands, ScriptingCommands, BasicCommands, ClusterCommands, SentinelCommands {

  protected JedisPoolAbstract dataSource = null;

  public Jedis() {
    super();
  }

  public Jedis(final String host) {
    super(host);
  }

  public Jedis(final String host, final int port) {
    super(host, port);
  }
............

Jedis对象调用父类BinaryJedis构造器：

public class BinaryJedis implements BasicCommands, BinaryJedisCommands, MultiKeyBinaryCommands,
        AdvancedBinaryJedisCommands, BinaryScriptingCommands, Closeable {
    protected Client client = null;
    protected Transaction transaction = null;
    protected Pipeline pipeline = null;

    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) {
        client = new Client(host, port);
    }

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

实际上，new Jedis()的初始化中。最重要的是new Client（）这句代码。

Client 继承自 BinaryClient

public class Client extends BinaryClient implements Commands {

  public Client() {
    super();
  }

而BinaryClient又继承自Collection

public class BinaryClient extends Connection {
 ............
  private String password;

  private int db;

  private boolean isInWatch;

............
  public BinaryClient() {
    super();
  }
............

接着我们来看Collection代码：

    public class Connection implements Closeable {
    .....
    protected Connection sendCommand(final ProtocolCommand cmd, final String... args) {
        final byte[][] bargs = new byte[args.length][];
        for (int i = 0; i < args.length; i++) {
            // 对cmd判空并返回bytes
            bargs[i] = SafeEncoder.encode(args[i]);
        }
        return sendCommand(cmd, bargs);
    }

    protected Connection sendCommand(final ProtocolCommand cmd) {
        return sendCommand(cmd, EMPTY_ARGS);
    }

    protected Connection sendCommand(final ProtocolCommand cmd, final byte[]... args) {
        try {
            // 1.建立Socket连接
            connect();
            // 2.依照协议完毕IO操作，也就是命令的运行
            Protocol.sendCommand(outputStream, cmd, args);
            return this;
        } catch (JedisConnectionException ex) {
            /*
             * When client send request which formed by invalid protocol, Redis
             * send back error message before close connection. We try to read
             * it to provide reason of failure.
             */
            try {
                String errorMessage = Protocol.readErrorLineIfPossible(inputStream);
                if (errorMessage != null && errorMessage.length() > 0) {
                    ex = new JedisConnectionException(errorMessage, ex.getCause());
                }
            } catch (Exception e) {
                /*
                 * Catch any IOException or JedisConnectionException occurred
                 * from InputStream#read and just ignore. This approach is safe
                 * because reading error message is optional and connection will
                 * eventually be closed.
                 */
            }
            // Any other exceptions related to connection?

            broken = true;
            throw ex;
        }
    }
    ...
    // 建立Sock连接
    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
                // <[email protected]_add

                socket.connect(new InetSocketAddress(host, port), connectionTimeout);
                socket.setSoTimeout(soTimeout);
                outputStream = new RedisOutputStream(socket.getOutputStream());
                inputStream = new RedisInputStream(socket.getInputStream());
            } catch (IOException ex) {
                broken = true;
                throw new JedisConnectionException(ex);
            }
        }
    }
    ...

在这里完毕了Socket连接。并返回这个Socket.

每次我们使用Jedis去运行命令。都是这个持有Soket的client去运行的。

比方：

    /**
     * Get the value of the specified key. If the key does not exist null is
     * returned. If the value stored at key is not a string an error is returned
     * because GET can only handle string values.
     * <p>
     * Time complexity: O(1)
     * 
     * @param key
     * @return Bulk reply
     */
    @Override
    public String get(final String key) {
        checkIsInMultiOrPipeline();// 检查是否在事物中；检查是否是哟好难过管道技术
        client.sendCommand(Protocol.Command.GET, key);// 使用Socket进行IO操作，运行命令
        return client.getBulkReply();
    }

jedis除了继承的BinaryJedis完毕主要的IO操作。还实现了 JedisCommands, MultiKeyCommands, AdvancedJedisCommands,ScriptingCommands, BasicCommands, ClusterCommands, SentinelCommands
这几个可使用的命令的接口。

你能够參考redis自带的 unitTest，更深入的理解。

http://download.csdn.net/detail/lemon89/9407039

关于soTimeout 与 connectionTimeOut

我不多说了，这个链接解释非常清楚。

http://stackoverflow.com/questions/7360520/connectiontimeout-versus-sockettimeout