知识点
FlinkTable步骤: // 1、创建表的执行环境 val tableEnv = ... // 2、创建一张表,用于读取数据 tableEnv.connect(...).createTemporaryTable("inputTable") // 3、1通过 Table API 查询算子,得到一张结果表 val result = tableEnv.from("inputTable").select(...) // 3、2通过 SQL 查询语句,得到一张结果表 val sqlResult = tableEnv.sqlQuery("SELECT ... FROM inputTable ...") // 4、注册一张表,用于把计算结果输出 tableEnv.connect(...).createTemporaryTable("outputTable") // 5、将结果表写入输出表中 result.insertInto("outputTable")
1、CSV文件依赖
<dependency> <groupId>org.apache.flink</groupId> <artifactId>flink-csv</artifactId> <version>1.10.1</version> </dependency>
<!-- old planner flink table-->
<dependency>
<groupId>org.apache.flink</groupId>
<artifactId>flink-table-planner_2.12</artifactId>
<version>1.10.1</version>
</dependency>
<!--new planner-->
<dependency>
<groupId>org.apache.flink</groupId>
<artifactId>flink-table-planner-blink_2.12</artifactId>
<version>1.10.1</version>
</dependency>
2、代码案例
package table import org.apache.flink.api.scala.ExecutionEnvironment import org.apache.flink.streaming.api.scala.StreamExecutionEnvironment import org.apache.flink.table.api.{DataTypes, EnvironmentSettings, Table, TableEnvironment} import org.apache.flink.table.api.scala.{BatchTableEnvironment, StreamTableEnvironment} import org.apache.flink.table.descriptors.{Csv, FileSystem, Kafka, OldCsv, Schema} import org.apache.flink.table.api.scala._ import org.apache.flink.streaming.api.scala._ /** * @author yangwj * @date 2021/1/12 21:53 * @version 1.0 */ object TableApiTest { def main(args: Array[String]): Unit = { //1、创建表执行环境、就得使用流式环境 val env: StreamExecutionEnvironment = StreamExecutionEnvironment.getExecutionEnvironment env.setParallelism(1) val tableEnv: StreamTableEnvironment = StreamTableEnvironment.create(env) /** //1、1老版本planner的流处理 val setttings = EnvironmentSettings.newInstance() .useOldPlanner() .inStreamingMode() .build() val oldStreamTableEnv: StreamTableEnvironment = StreamTableEnvironment.create(env, setttings) //1.2老版本的批处理 val batchEnv = ExecutionEnvironment.getExecutionEnvironment val oldBatchTableEnv: BatchTableEnvironment = BatchTableEnvironment.create(batchEnv) //1.1新版本,基于blink planner的流处理 val blinkStreamSettings: EnvironmentSettings = EnvironmentSettings.newInstance() .useBlinkPlanner() .inStreamingMode() .build() val blinkStreamTableEnv = StreamTableEnvironment.create(env,blinkStreamSettings) //1.2新版本,基于blink planner的批处理 val blinkBatchSettings: EnvironmentSettings = EnvironmentSettings.newInstance() .useBlinkPlanner() .inBatchMode() .build() val blinkBatchTableEnv = TableEnvironment.create(blinkBatchSettings) **/ //2、连接外部系统,读取数据,注册表 //2.1读取文件 val inputFile:String = "G:\Java\Flink\guigu\flink\src\main\resources\sensor.txt" tableEnv.connect(new FileSystem().path(inputFile)) // new OldCsv()是一个非标的格式描述 .withFormat(new Csv()) .withSchema(new Schema().field("id",DataTypes.STRING()) .field("timestamp",DataTypes.BIGINT()) .field("temperature",DataTypes.DOUBLE()) ) .createTemporaryTable("inputTable") val inputTable: Table = tableEnv.from("inputTable") inputTable.toAppendStream[(String,Long,Double)].print("result") //2.2读取kafka数据 tableEnv.connect(new Kafka() .version("0.11") .topic("Demo") .property("zookeeper.connect","localhost:2181") .property("bootstrap.servers","localhost:9092") ) .withFormat(new Csv()) .withSchema(new Schema().field("id",DataTypes.STRING()) .field("timestamp",DataTypes.BIGINT()) .field("temperature",DataTypes.DOUBLE()) ).createTemporaryTable("kafkaTable") val kafkaTable: Table = tableEnv.from("kafkaTable") kafkaTable.toAppendStream[(String,Long,Double)].print("kafkaResult") //3、查询转换 //3.1 使用table api val sensorTable: Table = tableEnv.from("inputTable") val apiResult: Table = sensorTable.select('id, 'temperature) .filter('id === "sensor_1") //3.2sql实现 val sqlResult: Table = tableEnv.sqlQuery( """ |select id ,temperature |from inputTable |where id = 'sensor_1' """.stripMargin) apiResult.toAppendStream[(String, Double)].print("apiResult") sqlResult.toAppendStream[(String, Double)].print("sqlResult") env.execute("table api test") } }