Steps in JSR 352 API Overview and use cases
JSR 352 is the specification of Java Batch, which provides developers with a simplified and standardized way to handle batch operations.It defines a set of APIs for creating, configuration and execution of batch processing operations.
The core concept of JSR 352 is steps.The step is the basic processing unit of the job, which can perform specific tasks, such as reading data, processing data, and writing data.Each step can be configured to perform specific tasks, and then multiple steps can be combined together to achieve complex batch processing processes.
The following is the main overview of steps in the JSR 352 API:
1. Step configuration: Specify its attributes and behaviors for each step.ItemReader, ItemProcessor, and Itemwriter can be configured with steps.You can define your own step components by expanding the abstract ItemReader, ItemProcessor, and itemwriter.
The following code example shows how to use the JSR 352 API to configure a simple step:
public class MyItemReader implements ItemReader<String> {
private String[] data = { "foo", "bar", "baz" };
private int index = 0;
public String readItem() {
if (index < data.length) {
return data[index++];
} else {
return null;
}
}
}
public class MyItemWriter implements ItemWriter<String> {
public void writeItems(List<String> items) {
for (String item : items) {
System.out.println(item);
}
}
}
public class MyStepConfig {
public Step configureStep() {
StepBuilder stepBuilder = BatchRuntime.getJobOperator().getFactory().createStepBuilder("myStep");
MyItemReader itemReader = new MyItemReader();
MyItemWriter itemWriter = new MyItemWriter();
Step step = stepBuilder
.<String, String>chunk(1)
.reader(itemReader)
.processor(new MyItemProcessor())
.writer(itemWriter)
.build();
return step;
}
}
In the above code, we created a step that contains a custom reader (MyItemReader), a processor, and a myitemwriter.The step uses a reading-processing-writing loop called chunk, and each data item is processed.
In addition to the step configuration, the JSR 352 also provides other functions, such as::
2. Division: Decompired large -scale assignments into multiple independent partitions for parallel execution.
3. Listener: execute custom operations when triggering different life cycle events in the operation and steps.
4. Error treatment: Define the abnormalities and faults in the steps.
These are important functions in the JSR 352 API, enabling developers to easily create and manage batch processing operations.By using JSR 352, developers can process a lot of data more efficiently and achieve complex data processing processes.
