案例一
需求
将DataStream注册为Table和View并进行SQL统计
代码实现
代码语言：javascript复制package cn.it.sql;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
import org.apache.flink.streaming.api.datastream.DataStream;
import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;
import org.apache.flink.table.api.Table;
import org.apache.flink.table.api.bridge.java.StreamTableEnvironment;
import java.util.Arrays;
import static org.apache.flink.table.api.Expressions.$;
/**
* Author lanson
* Desc
*/
public class FlinkSQL_Table_Demo01 {
public static void main(String[] args) throws Exception {
//1.准备环境
StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();
//EnvironmentSettings settings = EnvironmentSettings.newInstance().useBlinkPlanner().inStreamingMode().build();
//StreamTableEnvironment tEnv = StreamTableEnvironment.create(env, settings);
StreamTableEnvironment tEnv = StreamTableEnvironment.create(env);
//2.Source
DataStream<Order> orderA = env.fromCollection(Arrays.asList(
new Order(1L, "beer", 3),
new Order(1L, "diaper", 4),
new Order(3L, "rubber", 2)));
DataStream<Order> orderB = env.fromCollection(Arrays.asList(
new Order(2L, "pen", 3),
new Order(2L, "rubber", 3),
new Order(4L, "beer", 1)));
//3.注册表
// convert DataStream to Table
Table tableA = tEnv.fromDataStream(orderA, $("user"), $("product"), $("amount"));
// register DataStream as Table
tEnv.createTemporaryView("OrderB", orderB, $("user"), $("product"), $("amount"));
//4.执行查询
System.out.println(tableA);
// union the two tables
Table resultTable = tEnv.sqlQuery(
"SELECT * FROM " tableA " WHERE amount > 2 "
"UNION ALL "
"SELECT * FROM OrderB WHERE amount < 2"
);
//5.输出结果
DataStream<Order> resultDS = tEnv.toAppendStream(resultTable, Order.class);
resultDS.print();
env.execute();
}
@Data
@NoArgsConstructor
@AllArgsConstructor
public static class Order {
public Long user;
public String product;
public int amount;
}
}
