所有已知子接口:
ItemStreamReader<T>, PeekableItemReader<T>, ResourceAwareItemReaderItemStream<T>
所有已知实现类:
AbstractCursorItemReader, AbstractItemCountingItemStreamItemReader, AbstractItemStreamItemReader, AbstractNeo4jItemReader, AbstractPaginatedDataItemReader, AbstractPagingItemReader, AggregateItemReader, AmqpItemReader, ExceptionThrowingItemReaderProxy, FlatFileItemReader, GeneratingTradeItemReader, HibernateCursorItemReader, HibernatePagingItemReader, InfiniteLoopReader, ItemReaderAdapter, ItemReaderAdapter, IteratorItemReader, JdbcCursorItemReader, JdbcPagingItemReader, JmsItemReader, JpaPagingItemReader, JsonItemReader, LdifReader, ListItemReader, MappingLdifReader, MongoItemReader, MultiResourceItemReader, Neo4jItemReader, OrderItemReader, RepositoryItemReader, ResourcesItemReader, SingleItemPeekableItemReader, StagingItemReader, StaxEventItemReader, StoredProcedureItemReader, SynchronizedItemStreamReader
```
public interface ItemReader<T>
```
Strategy interface for providing the data.
Implementations are expected to be stateful and will be called multiple times for each batch, with each call to read() returning a different value and finally returning null when all input data is exhausted.
Implementations need not be thread-safe and clients of a ItemReader need to be aware that this is the case.
A richer interface (e.g. with a look ahead or peek) is not feasible because we need to support transactions in an asynchronous batch.
从以下版本开始:
1.0
作者:
Rob Harrop, Dave Syer, Lucas Ward, Mahmoud Ben Hassine

- 方法概要
  所有方法实例方法抽象方法
  修饰符和类型方法说明
  T read()
  Reads a piece of input data and advance to the next one.

- 方法详细资料
  - read
```
@Nullable
T read()
throws java.lang.Exception,
       UnexpectedInputException,
       ParseException,
       NonTransientResourceException
```
    Reads a piece of input data and advance to the next one. Implementations must return null at the end of the input data set. In a transactional setting, caller might get the same item twice from successive calls (or otherwise), if the first call was in a transaction that rolled back.
    返回:
    T the item to be processed or null if the data source is exhausted
    抛出:
    ParseException - if there is a problem parsing the current record (but the next one may still be valid)
    NonTransientResourceException - if there is a fatal exception in the underlying resource. After throwing this exception implementations should endeavour to return null from subsequent calls to read.
    UnexpectedInputException - if there is an uncategorised problem with the input data. Assume potentially transient, so subsequent calls to read might succeed.
    java.lang.Exception - if an there is a non-specific error.

接口 ItemReader<T>

方法概要

方法详细资料

read