344 lines
13 KiB
Markdown
344 lines
13 KiB
Markdown
The InfluxDB 3 [`influxdb3-java` Java client library](https://github.com/InfluxCommunity/influxdb3-java) integrates
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with Java application code to write and query data stored in {{% product-name %}}.
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InfluxDB client libraries provide configurable batch writing of data to {{% product-name %}}.
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Use client libraries to construct line protocol data, transform data from other formats
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to line protocol, and batch write line protocol data to InfluxDB HTTP APIs.
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InfluxDB 3 client libraries can query {{% product-name %}} using SQL or InfluxQL.
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The `influxdb3-java` Java client library wraps the Apache Arrow `org.apache.arrow.flight.FlightClient`
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in a convenient InfluxDB 3 interface for executing SQL and InfluxQL queries, requesting
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server metadata, and retrieving data from {{% product-name %}} using the Flight protocol with gRPC.
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- [Installation](#installation)
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- [Using Maven](#using-maven)
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- [Using Gradle](#using-gradle)
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- [Importing the client](#importing-the-client)
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- [API reference](#api-reference)
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- [Classes](#classes)
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- [InfluxDBClient interface](#influxdbclient-interface)
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- [Initialize with credential parameters](#initialize-with-credential-parameters)
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- [InfluxDBClient instance methods](#influxdbclient-instance-methods)
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- [InfluxDBClient.writePoint](#influxdbclientwritepoint)
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- [InfluxDBClient.query](#influxdbclientquery)
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#### Example: write and query data
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The following example shows how to use `influxdb3-java` to write and query data stored in {{% product-name %}}.
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{{% code-placeholders "DATABASE_NAME | DATABASE_TOKEN" %}}
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```java
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package com.influxdata.demo;
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import com.influxdb.v3.client.InfluxDBClient;
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import com.influxdb.v3.client.Point;
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import com.influxdb.v3.client.query.QueryOptions;
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import com.influxdb.v3.client.query.QueryType;
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import java.time.Instant;
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import java.util.stream.Stream;
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public class HelloInfluxDB {
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private static final String HOST_URL = "https://{{< influxdb/host >}}"; // your cluster URL
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private static final String DATABASE = "DATABASE_NAME"; // your InfluxDB database name
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private static final char[] TOKEN = System.getenv("DATABASE_TOKEN"); // a local environment variable that stores your database token
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// Create a client instance that writes and queries data in your database.
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public static void main(String[] args) {
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// Instantiate the client with your InfluxDB credentials
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try (InfluxDBClient client = InfluxDBClient.getInstance(HOST_URL, TOKEN, DATABASE)) {
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writeData(client);
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queryData(client);
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}
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catch (Exception e) {
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System.err.println("An error occurred while connecting to InfluxDB!");
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e.printStackTrace();
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}
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}
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// Use the Point class to construct time series data.
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private static void writeData(InfluxDBClient client) {
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Point point = Point.measurement("temperature")
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.setTag("location", "London")
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.setField("value", 30.01)
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.setTimestamp(Instant.now().minusSeconds(10));
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try {
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client.writePoint(point);
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System.out.println("Data is written to the database.");
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}
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catch (Exception e) {
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System.err.println("Failed to write data to the database.");
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e.printStackTrace();
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}
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}
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// Use SQL to query the most recent 10 measurements
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private static void queryData(InfluxDBClient client) {
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System.out.printf("--------------------------------------------------------%n");
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System.out.printf("| %-8s | %-8s | %-30s |%n", "location", "value", "time");
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System.out.printf("--------------------------------------------------------%n");
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String sql = "select time,location,value from temperature order by time desc limit 10";
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try (Stream<Object[]> stream = client.query(sql)) {
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stream.forEach(row -> System.out.printf("| %-8s | %-8s | %-30s |%n", row[1], row[2], row[0]));
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}
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catch (Exception e) {
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System.err.println("Failed to query data from the database.");
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e.printStackTrace();
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}
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}
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}
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```
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{{% cite %}}Source: [suyashcjoshi/SimpleJavaInfluxDB](https://github.com/suyashcjoshi/SimpleJavaInfluxDB/) on GitHub{{% /cite %}}
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{{% /code-placeholders %}}
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Replace the following:
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- {{% code-placeholder-key %}}`DATABASE_NAME`{{% /code-placeholder-key %}}:
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the name of your {{% product-name %}}
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[database](/influxdb3/version/admin/databases/) to read and write data to
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- {{% code-placeholder-key %}}`DATABASE_TOKEN`{{% /code-placeholder-key %}}: a
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local environment variable that stores your
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[token](/influxdb3/version/admin/tokens/database/)--the token must have
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read and write permissions on the specified database.
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### Run the example to write and query data
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1. Build an executable JAR for the project--for example, using Maven:
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<!--pytest.mark.skip-->
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```bash
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mvn package
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```
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2. In your terminal, run the `java` command to write and query data in your database:
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<!--pytest.mark.skip-->
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```bash
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java \
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--add-opens=java.base/java.nio=org.apache.arrow.memory.core,ALL-UNNAMED \
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-jar target/PROJECT_NAME.jar
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```
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Include the following in your command:
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- [`--add-opens=java.base/java.nio=org.apache.arrow.memory.core,ALL-UNNAMED`](https://arrow.apache.org/docs/java/install.html#id3): with Java version 9 or later and Apache Arrow version 16 or later, exposes JDK internals for Arrow.
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For more options, see the [Apache Arrow Java install documentation](https://arrow.apache.org/docs/java/install.html).
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- `-jar target/PROJECT_NAME.jar`: your `.jar` file to run.
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The output is the newly written data from your {{< product-name >}} database.
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## Installation
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Include `com.influxdb.influxdb3-java` in your project dependencies.
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{{< code-tabs-wrapper >}}
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{{% code-tabs %}}
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[Maven pom.xml](#)
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[Gradle dependency script](#)
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{{% /code-tabs %}}
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{{% code-tab-content %}}
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```xml
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<dependency>
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<groupId>com.influxdb</groupId>
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<artifactId>influxdb3-java</artifactId>
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<version>RELEASE</version>
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</dependency>
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```
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{{% /code-tab-content %}}
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{{% code-tab-content %}}
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<!--pytest.mark.skip-->
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```groovy
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dependencies {
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implementation group: 'com.influxdb', name: 'influxdb3-java', version: 'latest.release'
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}
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```
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{{% /code-tab-content %}}
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{{< /code-tabs-wrapper >}}
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## Importing the client
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The `influxdb3-java` client library package provides
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`com.influxdb.v3.client` classes for constructing, writing, and querying data
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stored in {{< product-name >}}.
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## API reference
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- [Interface InfluxDBClient](#interface-influxdbclient)
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- [Initialize with credential parameters](#initialize-with-credential-parameters)
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- [InfluxDBClient instance methods](#influxdbclient-instance-methods)
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- [InfluxDBClient.writePoint](#influxdbclientwritepoint)
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- [InfluxDBClient.query](#influxdbclientquery)
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## InfluxDBClient interface
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`InfluxDBClient` provides an interface for interacting with InfluxDB APIs for writing and querying data.
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The `InfluxDBClient.getInstance` constructor initializes and returns a client instance with the following:
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- A _write client_ configured for writing to the database.
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- An Arrow _Flight client_ configured for querying the database.
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To initialize a client, call `getInstance` and pass your credentials as one of
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the following types:
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- [parameters](#initialize-with-credential-parameters)
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- a [`ClientConfig`](https://github.com/InfluxCommunity/influxdb3-java/blob/main/src/main/java/com/influxdb/v3/client/config/ClientConfig.java)
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- a [database connection string](#initialize-using-a-database-connection-string)
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### Initialize with credential parameters
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{{% code-placeholders "host | database | token" %}}
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```java
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static InfluxDBClient getInstance(@Nonnull final String host,
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@Nullable final char[] token,
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@Nullable final String database)
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```
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{{% /code-placeholders %}}
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- {{% code-placeholder-key %}}`host`{{% /code-placeholder-key %}} (string): The host URL of the InfluxDB instance.
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- {{% code-placeholder-key %}}`database`{{% /code-placeholder-key %}} (string): The [database](/influxdb3/version/admin/databases/) to use for writing and querying.
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- {{% code-placeholder-key %}}`token`{{% /code-placeholder-key %}} (char array): A [database token](/influxdb3/version/admin/tokens/database/) with read/write permissions.
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#### Example: initialize with credential parameters
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{{% code-placeholders "DATABASE_NAME | DATABASE_TOKEN" %}}
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```java
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package com.influxdata.demo;
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import com.influxdb.v3.client.InfluxDBClient;
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import com.influxdb.v3.client.Point;
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import com.influxdb.v3.client.query.QueryOptions;
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import com.influxdb.v3.client.query.QueryType;
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import java.time.Instant;
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import java.util.stream.Stream;
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public class HelloInfluxDB {
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private static final String HOST_URL = "https://{{< influxdb/host >}}";
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private static final String DATABASE = "DATABASE_NAME";
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private static final char[] TOKEN = System.getenv("DATABASE_TOKEN");
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// Create a client instance, and then write and query data in InfluxDB.
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public static void main(String[] args) {
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try (InfluxDBClient client = InfluxDBClient.getInstance(HOST_URL, DATABASE_TOKEN, DATABASE)) {
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writeData(client);
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queryData(client);
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}
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catch (Exception e) {
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System.err.println("An error occurred while connecting to InfluxDB!");
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e.printStackTrace();
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}
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}
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}
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```
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{{% /code-placeholders %}}
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Replace the following:
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- {{% code-placeholder-key %}}`DATABASE_NAME`{{% /code-placeholder-key %}}:
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your {{% product-name %}} [database](/influxdb3/version/admin/databases/)
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- {{% code-placeholder-key %}}`DATABASE_TOKEN`{{% /code-placeholder-key %}}: a
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[database token](/influxdb3/version/admin/tokens/database/) that has
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the necessary permissions on the specified database.
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#### Default tags
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To include default [tags](/influxdb3/version/reference/glossary/#tag) in
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all written data, pass a `Map` of tag keys and values.
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```java
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InfluxDBClient getInstance(@Nonnull final String host,
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@Nullable final char[] token,
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@Nullable final String database,
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@Nullable Map<String, String> defaultTags)
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```
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### Initialize using a database connection string
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{{% code-placeholders "DATABASE_NAME | API_TOKEN" %}}
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```java
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"https://{{< influxdb/host >}}"
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+ "?token=DATABASE_TOKEN&database=DATABASE_NAME"
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```
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{{% /code-placeholders %}}
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Replace the following:
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- {{% code-placeholder-key %}}`DATABASE_NAME`{{% /code-placeholder-key %}}:
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your {{% product-name %}} [database](/influxdb3/version/admin/databases/)
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- {{% code-placeholder-key %}}`DATABASE_TOKEN`{{% /code-placeholder-key %}}: a
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[database token](/influxdb3/version/admin/tokens/database/) that has
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the necessary permissions on the specified database.
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### InfluxDBClient instance methods
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#### InfluxDBClient.writePoint
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To write points as line protocol to a database:
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1. [Initialize the `client`](#initialize-with-credential-parameters)--your
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token must have write permission on the specified database.
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2. Use the `com.influxdb.v3.client.Point` class to create time series data.
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3. Call the `client.writePoint()` method to write points as line protocol in your
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database.
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```java
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// Use the Point class to construct time series data.
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// Call client.writePoint to write the point in your database.
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private static void writeData(InfluxDBClient client) {
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Point point = Point.measurement("temperature")
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.setTag("location", "London")
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.setField("value", 30.01)
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.setTimestamp(Instant.now().minusSeconds(10));
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try {
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client.writePoint(point);
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System.out.println("Data written to the database.");
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}
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catch (Exception e) {
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System.err.println("Failed to write data to the database.");
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e.printStackTrace();
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}
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}
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```
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#### InfluxDBClient.query
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To query data and process the results:
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1. [Initialize the `client`](#initialize-with-credential-parameters)--the
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token must have read permission on the database you want to query.
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2. Call `client.query()` and provide your SQL query as a string.
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3. Use the result stream's built-in iterator to process row data.
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```java
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// Query the latest 10 measurements using SQL
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private static void queryData(InfluxDBClient client) {
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System.out.printf("--------------------------------------------------------%n");
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System.out.printf("| %-8s | %-8s | %-30s |%n", "location", "value", "time");
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System.out.printf("--------------------------------------------------------%n");
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String sql = "select time,location,value from temperature order by time desc limit 10";
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try (Stream<Object[]> stream = client.query(sql)) {
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stream.forEach(row -> System.out.printf("| %-8s | %-8s | %-30s |%n", row[1], row[2], row[0]));
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}
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catch (Exception e) {
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System.err.println("Failed to query data from the database.");
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e.printStackTrace();
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}
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}
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```
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<a class="btn" href="https://github.com/InfluxCommunity/influxdb3-java/" target="\_blank">View the InfluxDB 3 Java client library</a>
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