mirror of https://github.com/dapr/docs.git
java
Signed-off-by: Hannah Hunter <hannahhunter@microsoft.com>
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Hannah Hunter
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@ -17,7 +17,7 @@ In this Quickstart, you will schedule a batch script to run every 10 seconds usi
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Select your preferred language-specific Dapr SDK before proceeding with the Quickstart.
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{{< tabs "Python" "JavaScript" ".NET" "Go" >}}
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{{< tabs "Python" "JavaScript" ".NET" "Java" "Go" >}}
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<!-- Python -->
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{{% codetab %}}
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@ -614,6 +614,216 @@ In the YAML file:
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- `spec/type` specifies that PostgreSQL is used for this binding.
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- `spec/metadata` defines the connection to the PostgreSQL instance used by the component.
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{{% /codetab %}}
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<!-- Java -->
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{{% codetab %}}
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### Pre-requisites
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For this example, you will need:
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- [Dapr CLI and initialized environment](https://docs.dapr.io/getting-started).
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- Java JDK 11 (or greater):
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- [Oracle JDK](https://www.oracle.com/technetwork/java/javase/downloads/index.html#JDK11), or
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- [OpenJDK](https://jdk.java.net/13/)
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- [Apache Maven](https://maven.apache.org/install.html), version 3.x.
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<!-- IGNORE_LINKS -->
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- [Docker Desktop](https://www.docker.com/products/docker-desktop)
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<!-- END_IGNORE -->
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### Step 1: Set up the environment
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Clone the [sample provided in the Quickstarts repo](https://github.com/dapr/quickstarts/tree/master/bindings).
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```bash
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git clone https://github.com/dapr/quickstarts.git
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```
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### Step 2: Run PostgreSQL Docker container locally
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Run the [PostgreSQL instance](https://www.postgresql.org/) locally in a Docker container on your machine. The Quickstart sample includes a Docker Compose file to locally customize, build, run, and initialize the `postgres` container with a default `orders` table.
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In a terminal window, from the root of the Quickstarts clone directory, navigate to the `bindings/db` directory.
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```bash
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cd quickstarts/bindings/db
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```
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Run the following command to set up the container:
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```bash
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docker compose up
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```
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Verify that the container is running locally.
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```bash
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docker ps
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```
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The output should include:
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```bash
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CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
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55305d1d378b postgres "docker-entrypoint.s…" 3 seconds ago Up 2 seconds 0.0.0.0:5432->5432/tcp sql_db
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```
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### Step 3: Schedule a Cron job and write to the database
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In a new terminal window, navigate to the SDK directory.
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```bash
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cd quickstarts/bindings/java/sdk/batch
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```
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Install the dependencies:
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```bash
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mvn clean install
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```
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Run the `java-binding-quickstart-sdk` service alongside a Dapr sidecar.
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```bash
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dapr run --app-id java-binding-quickstart-sdk --app-port 8080 --components-path ../../../components -- java -jar target/BatchProcessingService-0.0.1-SNAPSHOT.jar
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```
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The code inside the `process_batch` function is executed every 10 seconds (defined in [`binding-cron.yaml`]({{< ref "#componentsbinding-cronyaml-component-file" >}}) in the `components` directory). The binding trigger looks for a route called via HTTP POST in your Flask application by the Dapr sidecar.
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```java
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@PostMapping(path = cronBindingPath, consumes = MediaType.ALL_VALUE)
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public ResponseEntity<String> processBatch() throws IOException, Exception
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```
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The `java-binding-quickstart-sdk` service uses the PostgreSQL output binding defined in the [`binding-postgres.yaml`]({{< ref "#componentbinding-postgresyaml-component-file" >}}) component to insert the `OrderId`, `Customer`, and `Price` records into the `orders` table.
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```java
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try (DaprClient client = new DaprClientBuilder().build()) {
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for (Order order : ordList.orders) {
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String sqlText = String.format(
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"insert into orders (orderid, customer, price) " +
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"values (%s, '%s', %s);",
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order.orderid, order.customer, order.price);
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logger.info(sqlText);
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Map<String, String> metadata = new HashMap<String, String>();
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metadata.put("sql", sqlText);
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// Invoke sql output binding using Dapr SDK
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client.invokeBinding(sqlBindingName, "exec", null, metadata).block();
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}
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logger.info("Finished processing batch");
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return ResponseEntity.ok("Finished processing batch");
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}
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```
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### Step 4: View the output of the job
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Notice, as specified above, the code invokes the output binding with the `OrderId`, `Customer`, and `Price` as a payload.
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Your output binding's `print` statement output:
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```
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== APP == 2022-06-22 16:39:17.012 INFO 35772 --- [nio-8080-exec-4] c.s.c.BatchProcessingServiceController : Processing batch..
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== APP == 2022-06-22 16:39:17.268 INFO 35772 --- [nio-8080-exec-4] c.s.c.BatchProcessingServiceController : insert into orders (orderid, customer, price) values (1, 'John Smith', 100.32);
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== APP == 2022-06-22 16:39:17.838 INFO 35772 --- [nio-8080-exec-4] c.s.c.BatchProcessingServiceController : insert into orders (orderid, customer, price) values (2, 'Jane Bond', 15.4);
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== APP == 2022-06-22 16:39:17.844 INFO 35772 --- [nio-8080-exec-4] c.s.c.BatchProcessingServiceController : insert into orders (orderid, customer, price) values (3, 'Tony James', 35.56);
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== APP == 2022-06-22 16:39:17.848 INFO 35772 --- [nio-8080-exec-4] c.s.c.BatchProcessingServiceController : Finished processing batch
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```
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In a new terminal, verify the same data has been inserted into the database. Navigate to the `bindings/db` directory.
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```bash
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cd quickstarts/bindings/db
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```
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Run the following to start the interactive Postgres CLI:
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```bash
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docker exec -i -t postgres psql --username postgres -p 5432 -h localhost --no-password
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```
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At the `admin=#` prompt, change to the `orders` table:
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```bash
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\c orders;
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```
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At the `orders=#` prompt, select all rows:
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```bash
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select * from orders;
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```
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The output should look like this:
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```
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orderid | customer | price
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---------+------------+--------
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1 | John Smith | 100.32
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2 | Jane Bond | 15.4
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3 | Tony James | 35.56
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```
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#### `components\binding-cron.yaml` component file
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When you execute the `dapr run` command and specify the component path, the Dapr sidecar:
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- Initiates the Cron [binding building block]({{< ref bindings >}})
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- Calls the binding endpoint (`batch`) every 10 seconds
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The Cron `binding-cron.yaml` file included for this Quickstart contains the following:
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```yaml
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apiVersion: dapr.io/v1alpha1
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kind: Component
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metadata:
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name: cron
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namespace: quickstarts
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spec:
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type: bindings.cron
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version: v1
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metadata:
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- name: schedule
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value: "@every 10s" # valid cron schedule
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```
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**Note:** The `metadata` section of `binding-cron.yaml` contains a [Cron expression]({{< ref cron.md >}}) that specifies how often the binding is invoked.
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#### `component\binding-postgres.yaml` component file
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When you execute the `dapr run` command and specify the component path, the Dapr sidecar:
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- Initiates the PostgreSQL [binding building block]({{< ref postgres.md >}})
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- Connects to PostgreSQL using the settings specified in the `binding-postgres.yaml` file
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With the `binding-postgres.yaml` component, you can easily swap out the backend database [binding]({{< ref supported-bindings.md >}}) without making code changes.
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The PostgreSQL `binding-postgres.yaml` file included for this Quickstart contains the following:
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```yaml
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apiVersion: dapr.io/v1alpha1
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kind: Component
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metadata:
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name: sqldb
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namespace: quickstarts
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spec:
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type: bindings.postgres
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version: v1
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metadata:
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- name: url # Required
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value: "user=postgres password=docker host=localhost port=5432 dbname=orders pool_min_conns=1 pool_max_conns=10"
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```
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In the YAML file:
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- `spec/type` specifies that PostgreSQL is used for this binding.
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- `spec/metadata` defines the connection to the PostgreSQL instance used by the component.
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{{% /codetab %}}
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<!-- Go -->
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@ -825,6 +1035,7 @@ Join the discussion in our [discord channel](https://discord.gg/22ZtJrNe).
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- [Python](https://github.com/dapr/quickstarts/tree/master/bindings/python/http)
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- [JavaScript](https://github.com/dapr/quickstarts/tree/master/bindings/javascript/http)
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- [.NET](https://github.com/dapr/quickstarts/tree/master/bindings/csharp/http)
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- [Java](https://github.com/dapr/quickstarts/tree/master/bindings/java/http)
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- [Go](https://github.com/dapr/quickstarts/tree/master/bindings/go/http)
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- Learn more about [Binding building block]({{< ref bindings >}})
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