Flink通过SQLClinet/Java代码创建kafka源表，指定Offset消费，并进行实时计算，最后sink到mysql表中

需要依赖包，并放到flink/lib目录中：

下载地址： https://ci.apache.org/projects/flink/flink-docs-release-1.10/dev/table/connect.html#jdbc-connector

1. flink-json-1.10.0-sql-jar.jar
2. flink-sql-connector-kafka_2.11-1.10.0.jar

1.通过自建kafka的生产者来产生数据

/bin/kafka-console-producter.sh --broker-list 192.168.58.177:9092 --topic my_topic

数据

{"user_id": "543462", "item_id":"1715", "category_id": "1464116", "behavior": "pv", "ts": "2017-11-26T01:00:00Z"}
{"user_id": "662867", "item_id":"2244074", "category_id": "1575622", "behavior": "pv", "ts": "2017-11-26T01:00:00Z"}
{"user_id": "662868", "item_id":"1784", "category_id": "54123654", "behavior": "pv", "ts": "2017-11-26T01:00:00Z"}
{"user_id": "662854", "item_id":"1456", "category_id": "12345678", "behavior": "pv", "ts": "2017-11-26T01:00:00Z"}
{"user_id": "662858", "item_id":"1457", "category_id": "12345679", "behavior": "pv", "ts": "2017-11-26T01:00:00Z"}

2.在kafka进行消费

/bin/kafka-console-consumer.sh --bootstrap-server 192.168.58.177:9092 --topic my_topic --partition 0 --offset 0

 第一种：在SqlClient上进行测试

3.在Flink的sqlclient 创建表

　　1. 这里需要注意，如果是指定Kafka的Offset消费，则参数 'connector.startup-mode' = 'specific-offsets'，并且需要添加参数 'connector.specific-offsets' = 'partition:0,offset:27'，这里需要指定分区以及从什么地方开始消费.下图中的topic消费到27，那么我们从27开始继续消费。

　　2. 查看目前topic消费的位置

./kafka-consumer-groups.sh --bootstrap-server 192.168.58.177:9092 --describe --group testGroup

CREATE TABLE user_log1 (
    user_id VARCHAR,
    item_id VARCHAR,
    category_id VARCHAR,
    behavior VARCHAR,
    ts VARCHAR
) WITH (
    'connector.type' = 'kafka',
    'connector.version' = 'universal',
    'connector.topic' = 'my-topic-one',
    'connector.startup-mode' = 'earliest-offset',-- optional: valid modes are "earliest-offset","latest-offset", "group-offsets",or "specific-offsets"
    'connector.properties.group.id' = 'testGroup',
    'connector.properties.zookeeper.connect' = '192.168.58.171:2181,192.168.58.177:2181,192.168.58.178:2181',
    'connector.properties.bootstrap.servers' = '192.168.58.177:9092',
    'format.type' = 'json'
);

实时计算 

select item_id,count(*) from user_log1 group by item_id;

 第二种，在java 项目中进行测试

代码：

    public static void main(String[] args) throws Exception {

        //创建flink运行环境
        StreamExecutionEnvironment Env = StreamExecutionEnvironment.getExecutionEnvironment();

        //创建tableEnvironment
        StreamTableEnvironment TableEnv =  StreamTableEnvironment.create(Env);

        TableEnv.sqlUpdate("CREATE TABLE user_log1 (
" +
                "    user_id VARCHAR,
" +
                "    item_id VARCHAR,
" +
                "    category_id VARCHAR,
" +
                "    behavior VARCHAR,
" +
                "    ts VARCHAR
" +
                ") WITH (
" +
                "    'connector.type' = 'kafka',
" +
                "    'connector.version' = 'universal',
" +
                "    'connector.topic' = 'my-topic-one',
" +
                "    'connector.startup-mode' = 'earliest-offset',
" + //optional: valid modes are "earliest-offset","latest-offset", "group-offsets",or "specific-offsets"
                "    'connector.properties.group.id' = 'testGroup',
" +
                "    'connector.properties.zookeeper.connect' = '192.168.58.171:2181,192.168.58.177:2181,192.168.58.178:2181',
" +
                "    'connector.properties.bootstrap.servers' = '192.168.58.177:9092',
" +
                "    'format.type' = 'json'
" +
                ")"
        ) ;

         Table result=TableEnv.sqlQuery("select user_id,count(*) from user_log1 group by user_id");
         //TableEnv.toAppendStream(result, Types.TUPLE(Types.INT,Types.LONG)).print();

         TableEnv.toRetractStream(result,Types.TUPLE(Types.STRING,Types.LONG)) .print();

         Env.execute("flink job");

    }

执行结果：