Java Session类代码示例

import com.datastax.driver.core.Session; //导入依赖的package包/类
private static ListenableFuture<ResultSet> executeAdaptiveQueryAsync(Session session, Statement statement, int fetchSize,
                                                                     int remainingAdaptations) {

    statement.setFetchSize(fetchSize);

    ResultSetFuture rawFuture = session.executeAsync(statement);

    // Lazily wrap the result set from the async result with an AdaptiveResultSet
    ListenableFuture<ResultSet> adaptiveFuture = Futures.transform(rawFuture, new Function<ResultSet, ResultSet>() {
        @Override
        public ResultSet apply(ResultSet resultSet) {
            return new AdaptiveResultSet(session, resultSet, remainingAdaptations);
        }
    });

    return Futures.withFallback(adaptiveFuture, t -> {
        if (isAdaptiveException(t) && remainingAdaptations > 0 && fetchSize > MIN_FETCH_SIZE) {
            // Try again with half the fetch size
            int reducedFetchSize = Math.max(fetchSize / 2, MIN_FETCH_SIZE);
            _log.debug("Repeating previous query with fetch size {} due to {}", reducedFetchSize, t.getMessage());
            return executeAdaptiveQueryAsync(session, statement, reducedFetchSize, remainingAdaptations - 1);
        }
        throw Throwables.propagate(t);
    });
}
 

import com.datastax.driver.core.Session; //导入依赖的package包/类
@Bean
public Session createSession(CassandraProperties properties, Cluster cluster) throws Exception {

    Session session = Retriable.wrap(cluster::connect)
        .withErrorMessage("Cannot connect to cassandra cluster")
        .retryOn(NoHostAvailableException.class)
        .withDelaySec(properties.getConnectDelaySec())
        .call();

    initDb(properties, session);

    if (!session.getCluster().getMetadata().checkSchemaAgreement()) {
        log.warn("SCHEMA IS NOT IN AGREEMENT!!!");
    }

    return session;
}
 

import com.datastax.driver.core.Session; //导入依赖的package包/类
/**
 * Test with incoming message containing a header with RegularStatement.
 */
@Test
public void testRequestMessageStatement() throws Exception {
    Update.Where update = update("camel_user")
            .with(set("first_name", bindMarker()))
            .and(set("last_name", bindMarker()))
            .where(eq("login", bindMarker()));
    Object response = producerTemplate.requestBodyAndHeader(new Object[]{"Claus 2", "Ibsen 2", "c_ibsen"},
            CassandraConstants.CQL_QUERY, update);

    Cluster cluster = CassandraUnitUtils.cassandraCluster();
    Session session = cluster.connect(CassandraUnitUtils.KEYSPACE);
    ResultSet resultSet = session.execute("select login, first_name, last_name from camel_user where login = ?", "c_ibsen");
    Row row = resultSet.one();
    assertNotNull(row);
    assertEquals("Claus 2", row.getString("first_name"));
    assertEquals("Ibsen 2", row.getString("last_name"));
    session.close();
    cluster.close();
}
 

import com.datastax.driver.core.Session; //导入依赖的package包/类
@Test
public void testDelayOnPreparedStatementWhenIgnoreOnPrepareIsFalse() throws Exception {
  Prime prime =
      PrimeDsl.when("select * from table where c1=?")
          .then(noRows())
          .delay(2, TimeUnit.SECONDS)
          .applyToPrepare()
          .build();
  HttpTestResponse response = server.prime(prime.getPrimedRequest());
  assertNotNull(response);
  RequestPrime responseQuery = om.readValue(response.body, RequestPrime.class);
  assertThat(responseQuery).isEqualTo(prime.getPrimedRequest());

  String contactPoint = HttpTestUtil.getContactPointString(server.getCluster(), 0);
  try (com.datastax.driver.core.Cluster cluster =
      defaultBuilder().addContactPoint(contactPoint).build()) {
    Session session = cluster.connect();
    long start = System.currentTimeMillis();
    session.prepare("select * from table where c1=?");
    long duration = System.currentTimeMillis() - start;
    // should have taken longer than 2 seconds.
    assertThat(duration).isGreaterThan(2000);
  }
}
 

import com.datastax.driver.core.Session; //导入依赖的package包/类
private void primeAndExecuteQueries(String[] primed, String[] queries) throws Exception {
  SuccessResult result = getSampleSuccessResult();
  for (String primeQuery : primed) {
    server.prime(when(primeQuery).then(result));
  }

  try (com.datastax.driver.core.Cluster driverCluster =
      defaultBuilder(server.getCluster())
          .withRetryPolicy(FallthroughRetryPolicy.INSTANCE)
          .build()) {
    Session session = driverCluster.connect();
    server.getCluster().clearLogs();
    for (String executeQuery : queries) {
      SimpleStatement stmt = new SimpleStatement(executeQuery);
      stmt.setDefaultTimestamp(100);
      session.execute(stmt);
    }
  }
}
 

import com.datastax.driver.core.Session; //导入依赖的package包/类
public static Session getClientSession(String hostAddr) {
    if(REGISTRY.containsKey(hostAddr)) {
        return REGISTRY.get(hostAddr);
    } else {
        Cluster.Builder clientClusterBuilder = new Cluster.Builder()
                .addContactPoint(hostAddr)
                .withQueryOptions(new QueryOptions()
                        .setConsistencyLevel(ConsistencyLevel.ONE)
                        .setSerialConsistencyLevel(ConsistencyLevel.LOCAL_SERIAL))
                .withoutJMXReporting()
                .withoutMetrics()
                .withReconnectionPolicy(new ConstantReconnectionPolicy(RECONNECT_DELAY_IN_MS));
        long startTimeInMillis = System.currentTimeMillis();
        Cluster clientCluster = clientClusterBuilder.build();
        Session clientSession = clientCluster.connect();

        LOG.info("Client session established after {} ms.", System.currentTimeMillis() - startTimeInMillis);
        REGISTRY.putIfAbsent(hostAddr, clientSession);
        return clientSession;
    }
}
 

import com.datastax.driver.core.Session; //导入依赖的package包/类
public static Session createSession(String ip, int port) {
    Cluster cluster;

    cluster = Cluster.builder()
            .addContactPoint(ip)
            .withPort(port)
            .build();

    Session session = cluster.connect();

    session.execute("CREATE KEYSPACE IF NOT EXISTS cassandrait WITH REPLICATION = { 'class' : 'SimpleStrategy', 'replication_factor' : 1 }");
    session.execute("DROP TABLE IF EXISTS cassandrait.counter");
    session.execute("CREATE TABLE cassandrait.counter (key text, value counter, PRIMARY key(key));");

    return session;
}
 

import com.datastax.driver.core.Session; //导入依赖的package包/类
@Override
	public Status selectByDevice(TsPoint point, Date startTime, Date endTime) {
		long costTime = 0L;
		Cluster cluster = null;
		try {
//			cluster = Cluster.builder().addContactPoint(CASSADRA_URL).build();
//			Session session = cluster.connect(KEY_SPACE_NAME);
			Session session = SessionManager.getSession();
			String selectCql = "SELECT * FROM point WHERE device_code='" + point.getDeviceCode() + "' and timestamp>="
					+ startTime.getTime() + " and timestamp<=" + endTime.getTime() + " ALLOW FILTERING";
//			System.out.println(selectCql);
			long startTime1 = System.nanoTime();
			ResultSet rs = session.execute(selectCql);
			long endTime1 = System.nanoTime();
			costTime = endTime1 - startTime1;
		} finally {
			if (cluster != null)
				cluster.close();
		}
//		System.out.println("此次查询消耗时间[" + costTime / 1000 + "]s");
		return Status.OK(costTime);
	}
 

import com.datastax.driver.core.Session; //导入依赖的package包/类
@Override
	public Status selectByDeviceAndSensor(TsPoint point, Date startTime, Date endTime) {
		long costTime = 0L;
		Cluster cluster = null;
		try {
//			cluster = Cluster.builder().addContactPoint(CASSADRA_URL).build();
//			Session session = cluster.connect(KEY_SPACE_NAME);
			Session session = SessionManager.getSession();
			String selectCql = "SELECT * FROM point WHERE device_code='" + point.getDeviceCode() + "' and sensor_code='"
					+ point.getSensorCode() + "' and timestamp>=" + startTime.getTime() + " and timestamp<="
					+ endTime.getTime() + " ALLOW FILTERING";
//			System.out.println(selectCql);
			long startTime1 = System.nanoTime();
			ResultSet rs = session.execute(selectCql);
			long endTime1 = System.nanoTime();
			costTime = endTime1 - startTime1;
		} finally {
			if (cluster != null)
				cluster.close();
		}
//		System.out.println("此次查询消耗时间[" + costTime / 1000 + "]s");
		return Status.OK(costTime);
	}
 

import com.datastax.driver.core.Session; //导入依赖的package包/类
@Override
	public Status selectMaxByDeviceAndSensor(String deviceCode, String sensorCode, Date startTime, Date endTime) {
		long costTime = 0L;
		Cluster cluster = null;
		try {
//			cluster = Cluster.builder().addContactPoint(CASSADRA_URL).build();
//			Session session = cluster.connect(KEY_SPACE_NAME);
			Session session = SessionManager.getSession();
			String selectCql = "SELECT MAX(value) FROM point WHERE device_code='" + deviceCode + "' and sensor_code='"
					+ sensorCode + "' and timestamp>=" + startTime.getTime() + " and timestamp<=" + endTime.getTime()
					+ " ALLOW FILTERING";
			long startTime1 = System.nanoTime();
//			System.out.println("aaa");
			ResultSet rs = session.execute(selectCql);
//			System.out.println("bbb");
			long endTime1 = System.nanoTime();
			costTime = endTime1 - startTime1;
		} finally {
			if (cluster != null)
				cluster.close();
		}
//		System.out.println("此次查询消耗时间[" + costTime / 1000 + "]s");
		return Status.OK(costTime);
	}
 

import com.datastax.driver.core.Session; //导入依赖的package包/类
@Override
	public Status selectMinByDeviceAndSensor(String deviceCode, String sensorCode, Date startTime, Date endTime) {
		long costTime = 0L;
		Cluster cluster = null;
		try {
			cluster = Cluster.builder().addContactPoint(CASSADRA_URL).build();
			Session session = cluster.connect(KEY_SPACE_NAME);
			String selectCql = "SELECT MIN(value) FROM point WHERE device_code='" + deviceCode + "' and sensor_code='"
					+ sensorCode + "' and timestamp>=" + startTime.getTime() + " and timestamp<=" + endTime.getTime()
					+ " ALLOW FILTERING";
//			System.out.println(selectCql);
			long startTime1 = System.nanoTime();
			ResultSet rs = session.execute(selectCql);
			long endTime1 = System.nanoTime();
			costTime = endTime1 - startTime1;
		} finally {
			if (cluster != null)
				cluster.close();
		}
//		System.out.println("此次查询消耗时间[" + costTime / 1000 + "]s");
		return Status.OK(costTime);
	}
 

import com.datastax.driver.core.Session; //导入依赖的package包/类
@Override
	public Status selectAvgByDeviceAndSensor(String deviceCode, String sensorCode, Date startTime, Date endTime) {
		long costTime = 0L;
		Cluster cluster = null;
		try {
			cluster = Cluster.builder().addContactPoint(CASSADRA_URL).build();
			Session session = cluster.connect(KEY_SPACE_NAME);
			String selectCql = "SELECT AVG(value) FROM point WHERE device_code='" + deviceCode + "' and sensor_code='"
					+ sensorCode + "' and timestamp>=" + startTime.getTime() + " and timestamp<=" + endTime.getTime()
					+ " ALLOW FILTERING";
//			System.out.println(selectCql);
			long startTime1 = System.nanoTime();
			ResultSet rs = session.execute(selectCql);
			long endTime1 = System.nanoTime();
			costTime = endTime1 - startTime1;
		} finally {
			if (cluster != null)
				cluster.close();
		}
//		System.out.println("此次查询消耗时间[" + costTime / 1000 + "]s");
		return Status.OK(costTime);
	}
 

import com.datastax.driver.core.Session; //导入依赖的package包/类
@Override
	public Status selectCountByDeviceAndSensor(String deviceCode, String sensorCode, Date startTime, Date endTime) {
		long costTime = 0L;
		Cluster cluster = null;
		try {
			cluster = Cluster.builder().addContactPoint(CASSADRA_URL).build();
			Session session = cluster.connect(KEY_SPACE_NAME);
			String selectCql = "SELECT COUNT(*) FROM point WHERE device_code='" + deviceCode + "' and sensor_code='"
					+ sensorCode + "' and timestamp>=" + startTime.getTime() + " and timestamp<=" + endTime.getTime()
					+ " ALLOW FILTERING";
//			System.out.println(selectCql);
			long startTime1 = System.nanoTime();
			ResultSet rs = session.execute(selectCql);
			long endTime1 = System.nanoTime();
			costTime = endTime1 - startTime1;
		} finally {
			if (cluster != null)
				cluster.close();
		}
//		System.out.println("此次查询消耗时间[" + costTime / 1000 + "]s");
		return Status.OK(costTime);
	}
 

import com.datastax.driver.core.Session; //导入依赖的package包/类
public static boolean untilApplied(Session session, BatchStatement.Type type, Consumer<BatchStatement> transaction) {
    for (int i = 1; i <= MAX_RETRY; i ++) {
        BatchStatement batchStatement = new BatchStatement(type);
        transaction.accept(batchStatement);
        if (batchStatement.size() == 0) return false;
        boolean applied;
        if (batchStatement.size() > 1) {
            applied = session.execute(batchStatement).wasApplied();
        } else {
            Statement statement = Iterables.getOnlyElement(batchStatement.getStatements());
            applied = session.execute(statement).wasApplied();
        }
        if (applied) return true;
        log.warn("Attempt {}/{} failed executing {}", i, MAX_RETRY, batchStatement);
        try {
            Thread.sleep(100 * i);
        } catch (InterruptedException e) {
            throw new AttemptsFailedException(e);
        }
    }
    throw new AttemptsFailedException();
}
 

import com.datastax.driver.core.Session; //导入依赖的package包/类
public static void executeSchemaCql(Session session, boolean deleteData) {
    try {
        
        URL schema = Resources.getResource("schema.cql");
        String schemaCql = Resources.toString(schema, Charset.forName("UTF-8"));
        schemaCql = schemaCql.replaceAll("(?m)//.*$", "");
        String[] statements = schemaCql.split(";");

        if (deleteData) {
            dropSchema(session);
        }

        for (String statement : statements) {
            statement = statement.trim();
            if (statement.isEmpty()) continue;
            executeWithLog(session, statement);
        }
    } catch (IOException e) {
        throw new RuntimeException(e);
    }
}