Spring Batch Read From File And Write To Database From Form



In this tutorial, we are taking a look at a student's question from my Spring Boot Introduction Course.

https://herehfil851.weebly.com/automation-studio-57-software-free-download.html. How can I read in a JSON file in Spring Boot and save the records to a database?

Read multiple queries. In Spring Batch framework, there are few ways to read data from a database. For simple SQL we can use org.springframework.batch.item.database.JdbcCursorItemReader. Below snippet code shows how to define a reader using JdbcCursorItemReader. May 30, 2015. Imac software versions free. While we develop a scalable project, we often have to process a large amount of data especially in the form of reading the data from a source (e.g. CSV file), process it (run business logic), and write to another source (database). Spring Batch Read From File And Write To Database From Form As seen in below code in step1 I'm reading users.xml and writing to database now in step2 I'm reading from userdetails.xml and writing to database but I need step1 auto generated key of tbluser for step2.

If you have ever had to read and write JSON data you know that this can be tricky. First, you have to read in the JSON data and mapping that data to your domain model isn't always easy. Once you have that in place you need to take that data and save it off to a database. In this tutorial, we will look at a quick and easy way to do this in Spring Boot.

Spring Boot Application

The first thing we need to do is to create a new Spring Boot application using the following dependencies.

JSON Data

The first thing we need to do is to get some dummy JSON data and one of my favorite services for doing this is JSON Placeholder. We are going to grab a list of users and save that to a file called users.json and place it inside of /src/main/resources/json/. Each JSON record for a user will look something like this.

Now that we have our list of users saved we need to model a domain after our user. We could create relationships between each of our domain models but to keep this simple I am going to store all of this data in a single user table. To accomplish this I am going to have embedded and embeddable domain models.

Spring batch read from file and write to database

Spring Boot REST Application

Now that we have our domain model in place we are going to build out a REST controller that uses a service & Repository to list and save data.

The important thing about our service here is that it takes a list of users and calls our repository to save them all at once.

Read & Write JSON Data to Database

With our application in place, there is only one step left to do. To read the JSON and write it to a database we are going to use a command line runner. When we bring in the Web dependency we also get the jackson-databind dependency. This contains an Object Mapper class which allows us to easily map JSON data to our domain model.

Using that Object Mapper and our well-crafted domain model from above we have what we need to accomplish our goal. We are going to read in our users.json file and then map that data to our domain model.

If we run our application and look at the H2 Database console we can see the 10 records have been inserted.

Spring Batch Read From Database And Write To File Example

Screencast

Conclusion

If you want to check out the source code for this project you can do so here.

Question: Are you facing any issues with JSON in your applications?

HowToDoInJava / Spring Batch / Spring Batch – Partitioning

Learn to use Spring batch partitioning to use multiple threads to process a range of data sets in a spring boot application.

Cisdem pdf converter

1. Parallel processing and Partitioning

1.1. Parallel processing

Mostly batch processing problems can be solved using single-threaded, but few complex scenarios like single-threaded processing taking a long time to perform tasks, where parallel processing is needed, can be achieved using multi-threaded models.

At a very high level, there are two modes of parallel processing:

  • Single process, multi-threaded
  • Multi-process

These break down into categories as well, as follows:

  • Multi-threaded Step (single process)
  • Parallel Steps (single process)
  • Remote Chunking of Step (multi process)
  • Partitioning a Step (single or multi process)

1.2. Partitioning in Spring batch

Partitioning uses multiple threads to process a range of data sets. The range of data sets can be defined programmatically. It’s on use case, how many threads we want to create to be used in a partition(s). The number of threads is purely based on the need/requirement.

Spring Batch is single threaded by default. In order to make the parallel processing, we need to Partition the steps of the batch job.

Partitioning is useful when we have millions of records to read from source systems and we can’t just rely on a single thread to process all records, which can be time-consuming. We want to use multiple threads to read and process data to effectively use the system resources.

2. Spring batch partitioning example

In this tutorial, we will read some data from a table and write it into another table. We can create millions of records into DB in order to experience how long the process would be if using Single thread batch processing. Here I have created few to understand how the program/concept works.

2.1. Maven dependencies

We used the latest version of Spring Boot as of today and by adding spring batch dependency, it will automatically pull the latest versions.

2.2. Partitioner

Partitioner is the central strategy interface for creating input parameters for a partitioned step in the form of ExecutionContext instances. The usual aim is to create a set of distinct input values, e.g. a set of non-overlapping primary key ranges, or a set of unique filenames.

Here we are querying the table to get the MAX and MIN id values (assuming they are sequential), and based on that we’re creating partitions between all records.

For partitioner, we have used gridSize = number of threads. Use your own custom value based on your requirements.

2.3. Job configuration

This is the job configuration class where we are creating the necessary bean to perform the job. In this example, we used SimpleAsyncTaskExecutor which is the simplest multi-threaded implementation of the TaskExecutorinterface.

We’ve used partitioner in the Step to create a partition step builder for a remote (or local) step.

Using these Step for each chunk of data ‘reading, processing and writing’, happens altogether in different threads. Hence, the processed records may not be in the same sequential order as fed into it.

Spring Boot Batch Read From File And Write To Database

Below are the things to look –

  • A throttle limit imposed on the task executor say, when it is backed by some thread pool. This limit defaults to 4 but can be configured differently.
  • Concurrency limits might comes on the resource used in the Step, say the DataSource used.
  • ColumnRangePartitioner – Central strategy interface for creating input parameters for a partitioned step in the form of ExecutionContext instances.
  • JdbcPagingItemReader – This bean read data using Pagination and accepts minValue and maxValue to be accept based on range to get those data only. Here we setFetchSize to 1000, however you can use any value and make it configurable from properties file.
  • JdbcBatchItemWriter – This bean will write the data into another table.
  • Step – This is step configure in the batch job. This is read data and write it into XML and JSON format
  • Job – Batch domain object representing a job

2.4 Entity and Mapper class

This is a business model class.

CustomerRowMapper class is used to map the resultset into the Customer domain object.

2.5. application.properties

Configuration to create DB connection with MySQL DB.

2.6. JDBC config and schema files

These are schema and SQL data files.

2.7. Demo

Spring Batch Read File And Write To Database

Run the application as Spring boot application.

The application will read the data from one database using partitions that we created and write it into another table.

Spring Batch Read From Database And Write To File

3. Conclusion

In this spring batch step partitioner tutorial, we learned to use partitioning to process bulk data using multiple threads. It enables the application to utilize the full potential of machine hardware and operating system capabilities.

Happy Learning !!

Spring Batch Read From File And Write To Database

Sourcecode Download

Was this article helpful?

TwitterFacebookLinkedInRedditPocket