Flink table&SQL 的使用

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>org.example</groupId>
    <artifactId>flink-sql</artifactId>
    <version>1.0-SNAPSHOT</version>
    <name>flink-sql</name>
    <!-- FIXME change it to the project's website -->
    <url>http://www.example.com</url>
    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <maven.compiler.source>1.7</maven.compiler.source>
        <maven.compiler.target>1.7</maven.compiler.target>
    </properties>
    <dependencies>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.11</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.apache.flink</groupId>
            <artifactId>flink-java</artifactId>
            <version>1.2.0</version>
        </dependency>
        <dependency>
            <groupId>org.apache.flink</groupId>
            <artifactId>flink-streaming-java_2.10</artifactId>
            <version>1.2.0</version>
        </dependency>
        <dependency>
            <groupId>org.apache.flink</groupId>
            <artifactId>flink-clients_2.10</artifactId>
            <version>1.2.0</version>
        </dependency>
        <dependency>
            <groupId>org.apache.flink</groupId>
            <artifactId>flink-table_2.10</artifactId>
            <version>1.2.0</version>
        </dependency>
    </dependencies>
    <build>
        <pluginManagement><!-- lock down plugins versions to avoid using Maven defaults (may be moved to parent pom) -->
            <plugins>
                <!-- clean lifecycle, see https://maven.apache.org/ref/current/maven-core/lifecycles.html#clean_Lifecycle -->
                <plugin>
                    <artifactId>maven-clean-plugin</artifactId>
                    <version>3.1.0</version>
                </plugin>
                <!-- default lifecycle, jar packaging: see https://maven.apache.org/ref/current/maven-core/default-bindings.html#Plugin_bindings_for_jar_packaging -->
                <plugin>
                    <artifactId>maven-resources-plugin</artifactId>
                    <version>3.0.2</version>
                </plugin>
                <plugin>
                    <artifactId>maven-compiler-plugin</artifactId>
                    <version>3.8.0</version>
                </plugin>
                <plugin>
                    <artifactId>maven-surefire-plugin</artifactId>
                    <version>2.22.1</version>
                </plugin>
                <plugin>
                    <artifactId>maven-jar-plugin</artifactId>
                    <version>3.0.2</version>
                </plugin>
                <plugin>
                    <artifactId>maven-install-plugin</artifactId>
                    <version>2.5.2</version>
                </plugin>
                <plugin>
                    <artifactId>maven-deploy-plugin</artifactId>
                    <version>2.8.2</version>
                </plugin>
                <!-- site lifecycle, see https://maven.apache.org/ref/current/maven-core/lifecycles.html#site_Lifecycle -->
                <plugin>
                    <artifactId>maven-site-plugin</artifactId>
                    <version>3.7.1</version>
                </plugin>
                <plugin>
                    <artifactId>maven-project-info-reports-plugin</artifactId>
                    <version>3.0.0</version>
                </plugin>
            </plugins>
        </pluginManagement>
    </build>
</project>

package org.example;
import org.apache.flink.api.java.DataSet;
import org.apache.flink.api.java.ExecutionEnvironment;
import org.apache.flink.api.java.operators.DataSource;
import org.apache.flink.table.api.Table;
import org.apache.flink.table.api.java.BatchTableEnvironment;
import java.util.ArrayList;
/**
 * Author : Jackson
 * Version : 2020/4/21 & 1.0
 */
public class SqlWordCount {
    public static void main(String[] args) throws Exception {
        //创建上下文环境
        ExecutionEnvironment env = ExecutionEnvironment.getExecutionEnvironment();
        BatchTableEnvironment fbtableEnv = BatchTableEnvironment.getTableEnvironment(env);
        String words = "hello Jackson hello flink";
        String[] split = words.split("\\W+");
        ArrayList<WC> list = new ArrayList<>();
        for (String word : split) {
            WC wc = new WC(word, 1);
            list.add(wc);
        }
        DataSource<WC> input = env.fromCollection(list);
        //DataSet 转sql，指定字段名
        Table table1 = fbtableEnv.fromDataSet(input, "word,count1");
        //table1.printSchema();
        //注册为一个表
        fbtableEnv.registerTable("WordCount", table1);
        Table table2 = fbtableEnv.sql("select word as word,sum(count1) as count1 from WordCount GROUP BY word");
        //将表转换DaraSet
        DataSet<WC> res = fbtableEnv.toDataSet(table2, WC.class);
        res.printToErr();
    }
    public static class WC {
        public String word;
        public long count1;
        public WC() {
        }
        public WC(String word, long count1) {
            this.word = word;
            this.count1 = count1;
        }
        @Override
        public String toString() {
            return word + "," + count1;
        }
    }
}