A JDBC driver implementation provides the low level details that allows a client to communicate with a third party datababase. I am just curious what it is doing behind the scenes. Communication between two systems written in different languages usually happens through web services.
Does the jdbc driver use web services to communicate between the client and the db server? Or am i oversimplifying?
People who write JDBC drivers have several options to choose from:
Type 1 driver: Use the generic JDBC-ODBC bridge, don't actually make a driver.
Type 2: Make a "wrapper" that uses JNI to call functions in a native client library.
Type 3: A generic driver that connects to a "middleware" service that talks with the database.
Type 4: a pure-Java implementation of the database communication protocol.
A type 3 driver might use web services to talk with the middleware. The other types of driver most likely communicate in a database-specific binary protocol over TCP/IP sockets (if the database is on a remote host) or other suitable reliable transport, not through web services.
You should check this link as this shows you how JDBC works.
Now coming to your question : No JDBC do not use web services. The way it connects to different types of databases is due to the database vendors because different database vendors provide their own driver implementation and you just need to use that implementation. There's nothing like web services. Each database vendor provides you with some api of their own to access database which they map to the Java's api to access database which is generic.
Java is provides a generic api for database operations which ultimately does operations and communication with database using sockets.
So what you need to read is TCP/IP , Socket programming, IO and JDBC. Please don't forget to check the link it will surely help you understand the concept.
Related
I use high-level-rest-client as my java client in my applicaton, and just use it by autowiring highRestClient in my business service code, not unlike using some connection pool in database connecting. For now, its performance is ok, but I wonder whether the bottom implementation of the client have use some kinds of connection pools. If not, is there any need to implement connection pools using high-level-rest-client on my own to improve its performance?
From the official Documentation RestHighLevelClient initialization, it looks like ES pools the connection.
The high-level client will internally create the low-level client used to perform requests based on the provided builder. That low-level client maintains a pool of connections and starts some threads so you should close the high-level client when you are well and truly done with it and it will in turn close the internal low-level client to free those resources. This can be done through the close
I'm connecting to Intersystems Cache database using Intersystems JDBC Driver. There are several network interfaces on client host. I need to make all the Cache traffic to go through a particular interface.
Is there a way to choose which network interface to use for Cache connection via JDBC Driver API or somehow via Java code? The approach to use ip route add is suitable but I'm looking for a Java-way like setLocalAddress() on some APIs or something.
I'm currently researching on Redis to retrieve data via UNIX sockets.
I've updated the redis.conf file to reflect this, by defining the path to redis.sock (in my case it is /tmp/redis.sock).
Using Spring Data Redis (via JedisConnectionFactory), I can see that it has methods for connecting to Redis via TCP (i.e. defining hostname and port). However, I don't see there being any methods used for connecting via UNIX sockets (unless I've overlooked something).
Does anyone know how I can connect to Redis using UNIX sockets via Spring Data Redis?
Any help/advice is appreciated.
Java cannot create or access Unix Domain Sockets without using a 3rd party (native) library.
That's correct in general. Jedis has (as of writing this answer) no Unix Domain Socket support. Lettuce and Redisson use netty for I/O which has support for native transports (epoll and kqueue). A native transport is required to use Unix Domain Sockets which depends on the underlying operating system.
Lettuce is integrated into Spring Data Redis but there's no native transport option yet.
References:
Jedis #492 Support Unix Domain Sockets
Lettuce: Reference documentation on Unix Domain Sockets
Redisson: Configuration of Unix Domain Sockets
Java cannot create or access Unix Domain Sockets without using a 3rd party (native) library.
And the spring-data-redis use the Jedis or Jredis or others as engine. Jedis does not support this method to connect. I think others do not support it also. Because the unix socket can only be used in local machine.
You can check this client library to make sure this.
You can use a workaround with socat. This is what I did for my DockerSwarmDiscoveryClient which required access to the /var/run/docker.sock but I only had the Spring WebClient which only supports TCP connections.
In a Docker context you can set up
daemon:
image: alpine/socat
command: tcp-listen:2375,fork,reuseaddr unix-connect:/var/run/docker.sock
volumes:
- /var/run/docker.sock:/var/run/docker.sock:ro
What are the advantages of using an HTTP Adapter in Worklight IBM to retrieve data from a Restful API instead of an ajax request? I think that using ajax is faster so why would one use such an adapter?
Take a look at the documentation and getting started modules.
Benefits of IBM Worklight adapters
Adapters provide various benefits, as follows:
Fast Development: Adapters are developed in JavaScript and XSL. Developers employ flexible and powerful server-side JavaScript to produce succinct and readable code for integrating with back-end applications and processing data. Developers can also use XSL to transform hierarchical back-end data to JSON.
Read-only and Transactional Capabilities: IBM Worklight adapters support read-only and transactional access modes to back-end systems.
Security: IBM Worklight adapters use flexible authentication facilities to create connections with back-end systems. Adapters offer control over the identity of the user with whom the connection is made. The user can be a system user, or a user on whose behalf the transaction is made.
Transparency: Data retrieved from back-end applications is exposed in a uniform manner, so that application developers can access data uniformly, regardless of its source, format, and protocol.
I build a service used thrift, and host it on a tomcat server by TServlet , the protocol is TCompactProtocol
I want to test the service by loadrunner, but i don't know how to record the test script
What protocol you would select for your thrift interface testing is entirely dependent upon the transport used in your implementation
http://thrift.apache.org/docs/concepts/
If raw TCP, then Winsock. If HTTP, then Web Virtual User (with Web_custom_requests() and recording headers), etc....
Note, not all interfaces are recordable. Some you will have to build code directly. With Thirft you ~~may~~ be able to build a client using the Java template virtual user type.
If this is your first venture into sockets of Java virtual user types then you will want to have a mentor with you for the ride. Otherwise its going to be extremely painful and far less fruitful than it should be.