other: add jdbc consumer demo

examples/JDBC/consumer-demo/pom.xml

+<?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>com.taosdata</groupId>
+    <artifactId>consumer</artifactId>
+    <version>1.0-SNAPSHOT</version>
+
+    <properties>
+        <maven.compiler.source>8</maven.compiler.source>
+        <maven.compiler.target>8</maven.compiler.target>
+    </properties>
+
+    <dependencies>
+        <dependency>
+            <groupId>com.taosdata.jdbc</groupId>
+            <artifactId>taos-jdbcdriver</artifactId>
+            <version>3.2.1</version>
+        </dependency>
+        <dependency>
+            <groupId>com.google.guava</groupId>
+            <artifactId>guava</artifactId>
+            <version>30.1.1-jre</version>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-assembly-plugin</artifactId>
+                <version>3.3.0</version>
+                <executions>
+                    <execution>
+                        <id>ConsumerDemo</id>
+                        <configuration>
+                            <finalName>ConsumerDemo</finalName>
+                            <archive>
+                                <manifest>
+                                    <mainClass>com.taosdata.ConsumerDemo</mainClass>
+                                </manifest>
+                            </archive>
+                            <descriptorRefs>
+                                <descriptorRef>jar-with-dependencies</descriptorRef>
+                            </descriptorRefs>
+                        </configuration>
+                        <phase>package</phase>
+                        <goals>
+                            <goal>single</goal>
+                        </goals>
+                    </execution>
+                </executions>
+            </plugin>
+
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <configuration>
+                    <source>8</source>
+                    <target>8</target>
+                    <encoding>UTF-8</encoding>
+                </configuration>
+            </plugin>
+
+        </plugins>
+    </build>
+
+</project>
\ No newline at end of file

examples/JDBC/consumer-demo/readme.md

+# How to Run the Consumer Demo Code On Linux OS
+TDengine's Consumer demo project is organized in a Maven way so that users can easily compile, package and run the project. If you don't have Maven on your server, you may install it using
+```
+sudo apt-get install maven
+```
+
+## Install TDengine Client
+Make sure you have already installed a tdengine client on your current develop environment.
+Download the tdengine package on our website: ``https://www.taosdata.com/cn/all-downloads/`` and install the client.
+
+## Run Consumer Demo using mvn plugin
+run command:
+```
+mvn clean compile exec:java -Dexec.mainClass="com.taosdata.ConsumerDemo"
+```
+
+## Custom configuration
+```shell
+# the host of TDengine server
+export TAOS_HOST="127.0.0.1"
+
+# the port of TDengine server
+export TAOS_PORT="6041"
+
+# the consumer type, can be "ws" or "jni"
+export TAOS_TYPE="ws"
+
+# the number of consumers
+export TAOS_JDBC_CONSUMER_NUM="1"
+
+# the number of processors to consume
+export TAOS_JDBC_PROCESSOR_NUM="2"
+
+# the number of records to be consumed per processor per second
+export TAOS_JDBC_RATE_PER_PROCESSOR="1000"
+
+# poll wait time in ms
+export TAOS_JDBC_POLL_SLEEP="100"
+```
+
+## Run Consumer Demo using jar
+
+To compile the demo project, go to the source directory ``TDengine/tests/examples/JDBC/consumer-demo`` and execute
+```
+mvn clean package assembly:single
+```
+
+To run ConsumerDemo.jar, go to ``TDengine/tests/examples/JDBC/consumer-demo`` and execute
+```
+java -jar target/ConsumerDemo-jar-with-dependencies.jar
+```
+

examples/JDBC/consumer-demo/src/main/java/com/taosdata/Bean.java

+package com.taosdata;
+
+import java.sql.Timestamp;
+
+public class Bean {
+    private Timestamp ts;
+    private Integer c1;
+    private String c2;
+
+    public Timestamp getTs() {
+        return ts;
+    }
+
+    public void setTs(Timestamp ts) {
+        this.ts = ts;
+    }
+
+    public Integer getC1() {
+        return c1;
+    }
+
+    public void setC1(Integer c1) {
+        this.c1 = c1;
+    }
+
+    public String getC2() {
+        return c2;
+    }
+
+    public void setC2(String c2) {
+        this.c2 = c2;
+    }
+
+    @Override
+    public String toString() {
+        final StringBuilder sb = new StringBuilder("Bean {");
+        sb.append("ts=").append(ts);
+        sb.append(", c1=").append(c1);
+        sb.append(", c2='").append(c2).append('\'');
+        sb.append('}');
+        return sb.toString();
+    }
+}

examples/JDBC/consumer-demo/src/main/java/com/taosdata/BeanDeserializer.java

+package com.taosdata;
+
+import com.taosdata.jdbc.tmq.ReferenceDeserializer;
+
+public class BeanDeserializer extends ReferenceDeserializer<Bean> {
+}

examples/JDBC/consumer-demo/src/main/java/com/taosdata/Config.java

+package com.taosdata;
+
+public class Config {
+    public static final String TOPIC = "test_consumer";
+    public static final String TAOS_HOST = "127.0.0.1";
+    public static final String TAOS_PORT = "6041";
+    public static final String TAOS_TYPE = "ws";
+    public static final int TAOS_JDBC_CONSUMER_NUM = 1;
+    public static final int TAOS_JDBC_PROCESSOR_NUM = 2;
+    public static final int TAOS_JDBC_RATE_PER_PROCESSOR = 1000;
+    public static final int TAOS_JDBC_POLL_SLEEP = 100;
+
+    private final int consumerNum;
+    private final int processCapacity;
+    private final int rate;
+    private final int pollSleep;
+    private final String type;
+    private final String host;
+    private final String port;
+
+    public Config(String type, String host, String port, int consumerNum, int processCapacity, int rate, int pollSleep) {
+        this.type = type;
+        this.consumerNum = consumerNum;
+        this.processCapacity = processCapacity;
+        this.rate = rate;
+        this.pollSleep = pollSleep;
+        this.host = host;
+        this.port = port;
+    }
+
+    public int getConsumerNum() {
+        return consumerNum;
+    }
+
+    public int getProcessCapacity() {
+        return processCapacity;
+    }
+
+    public int getRate() {
+        return rate;
+    }
+
+    public int getPollSleep() {
+        return pollSleep;
+    }
+
+    public String getHost() {
+        return host;
+    }
+
+    public String getPort() {
+        return port;
+    }
+
+    public String getType() {
+        return type;
+    }
+
+    public static Config getFromENV() {
+        String host = System.getenv("TAOS_HOST") != null ? System.getenv("TAOS_HOST") : TAOS_HOST;
+        String port = System.getenv("TAOS_PORT") != null ? System.getenv("TAOS_PORT") : TAOS_PORT;
+        String type = System.getenv("TAOS_TYPE") != null ? System.getenv("TAOS_TYPE") : TAOS_TYPE;
+
+        String c = System.getenv("TAOS_JDBC_CONSUMER_NUM");
+        int num = c != null ? Integer.parseInt(c) : TAOS_JDBC_CONSUMER_NUM;
+
+        String p = System.getenv("TAOS_JDBC_PROCESSOR_NUM");
+        int capacity = p != null ? Integer.parseInt(p) : TAOS_JDBC_PROCESSOR_NUM;
+
+        String r = System.getenv("TAOS_JDBC_RATE_PER_PROCESSOR");
+        int rate = r != null ? Integer.parseInt(r) : TAOS_JDBC_RATE_PER_PROCESSOR;
+
+        String s = System.getenv("TAOS_JDBC_POLL_SLEEP");
+        int sleep = s != null ? Integer.parseInt(s) : TAOS_JDBC_POLL_SLEEP;
+
+        return new Config(type, host, port, num, capacity, rate, sleep);
+    }
+}

examples/JDBC/consumer-demo/src/main/java/com/taosdata/ConsumerDemo.java

+package com.taosdata;
+
+import com.taosdata.jdbc.tmq.TMQConstants;
+
+import java.sql.Connection;
+import java.sql.DriverManager;
+import java.sql.SQLException;
+import java.sql.Statement;
+import java.util.Properties;
+import java.util.concurrent.Executors;
+import java.util.concurrent.ScheduledExecutorService;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicInteger;
+
+import static com.taosdata.Config.*;
+
+public class ConsumerDemo {
+    public static void main(String[] args) throws SQLException {
+        // Config
+        Config config = Config.getFromENV();
+        // Generated data
+        mockData();
+
+        Properties prop = new Properties();
+        prop.setProperty(TMQConstants.CONNECT_TYPE, config.getType());
+        prop.setProperty(TMQConstants.BOOTSTRAP_SERVERS, config.getHost() + ":" + config.getPort());
+        prop.setProperty(TMQConstants.CONNECT_USER, "root");
+        prop.setProperty(TMQConstants.CONNECT_PASS, "taosdata");
+        prop.setProperty(TMQConstants.MSG_WITH_TABLE_NAME, "true");
+        prop.setProperty(TMQConstants.ENABLE_AUTO_COMMIT, "true");
+        prop.setProperty(TMQConstants.GROUP_ID, "gId");
+        prop.setProperty(TMQConstants.VALUE_DESERIALIZER, "com.taosdata.BeanDeserializer");
+        for (int i = 0; i < config.getConsumerNum() - 1; i++) {
+            new Thread(new Worker(prop, config)).start();
+        }
+        new Worker(prop, config).run();
+    }
+
+    public static void mockData() throws SQLException {
+        String dbName = "test_consumer";
+        String tableName = "st";
+        String url = "jdbc:TAOS-RS://" + TAOS_HOST + ":" + TAOS_PORT + "/?user=root&password=taosdata&batchfetch=true";
+        Connection connection = DriverManager.getConnection(url);
+        Statement statement = connection.createStatement();
+        statement.executeUpdate("create database if not exists " + dbName + " WAL_RETENTION_PERIOD 3650");
+        statement.executeUpdate("use " + dbName);
+        statement.executeUpdate("create table if not exists " + tableName + " (ts timestamp, c1 int, c2 nchar(100)) ");
+        statement.executeUpdate("create topic if not exists " + TOPIC + " as select ts, c1, c2 from " + tableName);
+
+        ScheduledExecutorService scheduledExecutorService = Executors.newSingleThreadScheduledExecutor(r -> {
+            Thread t = new Thread(r);
+            t.setName("mock-data-thread-" + t.getId());
+            return t;
+        });
+        AtomicInteger atomic = new AtomicInteger();
+        scheduledExecutorService.scheduleWithFixedDelay(() -> {
+            int i = atomic.getAndIncrement();
+            try {
+                statement.executeUpdate("insert into " + tableName + " values(now, " + i + ",'" + i + "')");
+            } catch (SQLException e) {
+                // ignore
+            }
+        }, 0, 10, TimeUnit.MILLISECONDS);
+    }
+}

examples/JDBC/consumer-demo/src/main/java/com/taosdata/Worker.java

+package com.taosdata;
+
+import com.google.common.util.concurrent.RateLimiter;
+import com.taosdata.jdbc.tmq.ConsumerRecord;
+import com.taosdata.jdbc.tmq.ConsumerRecords;
+import com.taosdata.jdbc.tmq.TaosConsumer;
+
+import java.sql.SQLException;
+import java.time.Duration;
+import java.time.LocalDateTime;
+import java.util.Collections;
+import java.util.Properties;
+import java.util.concurrent.ForkJoinPool;
+import java.util.concurrent.Semaphore;
+
+public class Worker implements Runnable {
+
+    int sleepTime;
+    int rate;
+
+    ForkJoinPool pool = new ForkJoinPool();
+    Semaphore semaphore;
+
+    TaosConsumer<Bean> consumer;
+
+    public Worker(Properties prop, Config config) throws SQLException {
+        consumer = new TaosConsumer<>(prop);
+        consumer.subscribe(Collections.singletonList(Config.TOPIC));
+        semaphore = new Semaphore(config.getProcessCapacity());
+        sleepTime = config.getPollSleep();
+        rate = config.getRate();
+    }
+
+    @Override
+    public void run() {
+        while (!Thread.interrupted()) {
+            try {
+                // 控制请求频率
+                if (semaphore.tryAcquire()) {
+                    ConsumerRecords<Bean> records = consumer.poll(Duration.ofMillis(sleepTime));
+                    pool.submit(() -> {
+                        RateLimiter limiter = RateLimiter.create(rate);
+                        try {
+                            for (ConsumerRecord<Bean> record : records) {
+                                // 流量控制
+                                limiter.acquire();
+                                // 业务处理数据
+                                System.out.println("[" + LocalDateTime.now() + "] Thread id:" + Thread.currentThread().getId() + " -> " + record.value());
+                            }
+                        } finally {
+                            semaphore.release();
+                        }
+                    });
+                }
+            } catch (SQLException e) {
+                e.printStackTrace();
+            }
+        }
+    }
+}