Here you will find examples demonstrating Vert.x core in action.
Vert.x core provides fairly low level functionality for a diverse range of functions including HTTP, TCP, UDP, WebSockets, file system access, timers, verticles and more. Please consult the Vert.x core manual for detailed documentation on Vert.x core.
Examples can be run directly from the IDE by executing the main method.
To use Vert.x core in your own Maven or Gradle project add the following dependency
Group ID: io.vertx Artifact ID: vertx-core
Vert.x core can be embedded in any Java class and run that way if you like.
The Java embedded example shows an example of that. Just right-click the class in your IDE to run it directly.
These examples demonstrate usage of Vert.x net servers and clients - these are used for TCP (and SSL) servers and clients.
This example consists of an echo server verticle which serves TCP connections, and simply echoes back on the connection whatever it receives.
You can run the echo server then run telnet localhost 1234 from a console to connect to it. Type some stuff and see it
echoed back to you.
It also contains an echo client, which creates a connection to the server, sends some data and logs out what it receives back. You can use that as an alternative to connecting via telnet.
This is the same as the Echo example but using SSL to encrypt connections
These examples demonstrate usage of HTTP with Vert.x.
A very simple HTTP server which always responds with the same response:
You can run the server then open a browser and point it at http://localhost:8080
And a simple HTTP client which makes a request to the server.
Demonstrate how to use client side load balancing
Like the simple example, but using HTTPS instead of HTTP
You can run the server then open a browser and point it at http://localhost:4443
And a simple HTTPS client which makes a request to the server.
Connecting to a web server using a proxy. The proxy receives requests and connects to the endpoint server using a socket, then pass all the events between the client and the proxied server.
A simple toy HTTP proxy. The proxy receives requests and forwards them to the endpoint server, it also takes responses from the other server and passes them back to the client.
This example demonstrates how you can serve static files from disk using a Vert.x http server.
You can run the server then open a browser and point it at http://localhost:8080
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Note
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in practice, you would probably actually use Vert.x-Web for this rather than writing a web server at this low level. Serving files manually like this can leave you open to security exploits, e.g. by clients crafting URI paths which try to access resources outside the permitted area. Vert.x-Web provides URI path normalisation to avoid these kinds of exploits and comes with a static file handler which also handles caching headers and other features that you would probably want when serving static files in a web application. |
This example demonstrates how you can handle an HTML form on the server.
You can run the server then open a browser and point it at http://localhost:8080
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Note
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In practice, you would probably also use Vert.x-Web for this rather than writing a server at this low level. Vert.x-Web provides built in support for HTML forms, and avoids some security issues due to maliciously crafted URI paths. |
This example demonstrates how you can handle file uploads from an HTML form submission.
You can run the server then open a browser and point it at http://localhost:8080
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Note
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In practice, you would probably also use Vert.x-Web for this rather than writing a server at this low level. Vert.x-Web provides built in support for HTML forms and file uploads, and avoids some security issues due to maliciously crafted URI paths. |
This examples demonstrates an HTTP server receiving a request and piping the request body to a file on disk without ever storing the entire request body fully in memory.
There’s also a client which sends a request to the server and pipes a file from disk to the HTTP request body. The file is uploaded successfully even if the file is very large (GigaBytes).
A server that illustrates the round-robin orchestrated by vert.x when several verticles are opening HTTP servers on the same port:
The Servers deploys two instances of the HttpServerVerticle verticle.
You can run the server then open a browser and point it at link:http://localhost:8080. Requests will be handled by an instance after the other.
The Client illustrates the round-robin by periodically requesting the server and displays the response content.
This example shows a Vert.x HTTP server which handles websockets connections. This example simply echoes back to the client whatever it receives on the websocket.
There’s also a client which connects to the server, sends some data and logs out what it receives.
You can run the server then open a browser and point it at http://localhost:8080
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Note
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in practice, you would probably use Vert.x-Web to build a web application that uses WebSockets |
This example shows how to configure the Vert.x HTTP server for graceful shutdown.
The server replies to requests with a greeting, after a fixed delay.
When the server receives a request, the server verticle is un-deployed.
The verticle stop() method is invoked.
In this method, the server shutdown sequence is initiated.
The server stops accepting requests after the shutdown sequence is initiated. However, it’s not effectively stopped until all pending requests have been handled.
This is why the client gets its response, even if it takes the server some time to complete processing.
This example shows how to connect to an HTTP server and obtain an un-pooled connection managed fully by the client.
The server is a simple plain hello-world style HTTP server.
As usual the client interacts with the server, but instead of using its HTTP client to interact with the server, it opens a connection to the server and then interacts with the server.
This demonstrates a client managing its own connection to a server instead of relying on the client internal connection pools.
These examples demonstrate usage of HTTP/2 with Vert.x.
A very simple HTTP/2 server which always responds with the same response:
You can run the server then open a browser and point it at http://localhost:8080
And a simple HTTP/2 client which makes a request to the server.
This example shows HTTP/2 push.
The server pushes script.js along with index.html:
You can run the server then open a browser and point it at http://localhost:8080
And a client sets a push handler to be notified of the incoming server side pushes:
Like the simple server but using clear text, also known as h2c, without TLS:
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Note
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this example won’t work with browsers are they don’t support h2c |
HTTP/2 can be extended with custom frames, this example shows how to write and receive custom frames:
These examples demonstrate usage of the event bus in Vert.x
This example demonstrates point to point messaging between a receiver and a sender.
The receiver listens on an address on the event bus for incoming messages. When it receives a message it replies to it.
The sender sends a message to that address every second, when it receives a reply it logs it.
This example demonstrates publish / subscribe messaging between a receivers and a sender. With pub/sub messaging you can have multiple subscribers who all receive messages from publishers.
A receiver listens on an address on the event bus for incoming messages. When it receives a message it logs it.
The sender sends a message to that address every second, when it receives a reply it logs it.
You can start as many senders or receivers as you like.
This example demonstrates how to write custom MessageCodec for send / publish / receive any type of object. It means you can send or receive custom data type objects directly through EventBus as well as primitive types like String.
In this example, there are two type of receivers.
The first one is a local type which is deployed from sender, the other one is a cluster-wide type that launched from another instance of cluster.
So you can see how MessageCodec works differently on the local EventBus and clustered EventBus.
Java event bus sender Java event bus local receiver Java event bus cluster-wide receiver Java event bus custom message codec
You can start as many senders or receivers as you like.
This example demonstrates point to point messaging between a receiver and a sender with a transport level encryption.
The receiver listens on an address on the event bus for incoming messages. When it receives a message it replies to it.
The sender sends a message to that address every second, when it receives a reply it logs it.
Examples using Vert.x Futures are available in the Future directory.
These examples show verticles being deployed and undeployed.
This example shows a verticle deploying another verticle in several ways including:
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Deploying without waiting for it to deploy
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Deploying and waiting for it to deploy
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Passing configuration to another verticle during deploy
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Deploying more than one instance
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Deploying as a worker verticle
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Undeploying a verticle deployment explicitly
This is similar to the deployment example, but it shows how the start and stop of a verticle can be asynchronous. This is useful if the verticle has some startup or cleanup to do that takes some time, and we wish to avoid blocking the event loop.
A simple example illustrating how worker verticle can be created and the thread switches when interacting with them. The worker verticle is not System.out.println(Thread.currentThread()); ed in the event loop and so can do blocking operations.
This example demonstrates how you can include blocking code in with your non-blocking code in a way that doesn’t block an event loop:
Run the example then open a browser and point it at http://localhost:8080
Run the example then open a browser and point it at http://localhost:8080
A simple example illustrating how to use the streaming JsonParser to parse a giant array of small objects.
An example illustrating how to create your custom prefix length protocol to read and write objects in wire. The example uses Batch object, ReadStream and WriteStream implementation.
The protocol structure for Batch object is simple as illustrated below:
Length : uInt32 Type : byte ['O' for JsonObject | 'A' for JsonArray | 'B' for Buffer] Payload : Buffer