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[Feature Request]: Implement JsonIO.read() / readRows() for the Java SDK

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#40,086 1 comentario 0 reacciones 1 asignado Ver en GitHub

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@nitinware ya está trabajando en esto.

Desde el 9/9/2026.

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Descripción

io java new feature P2
What would you like to happen?

Motivation

The Java JsonIO connector (sdks/java/io/json/.../JsonIO.java) currently supports only writing withJsonIO.write() and JsonIO.writeRows(). There is no read path. The connector's own class Javadoc acknowledges this gap:

"Reading from JSON files is not yet implemented in Java. Please see
https://github.com/apache/beam/issues/24552."

That linked issue (#24552) is actually titled "Implement CsvIO.Read" and is closed as not planned, CsvIO.Read was subsequently implemented under a different path, so there is currently no live tracking issue for JSON reading, and the Javadoc reference is stale. This issue is intended to be that tracking issue.

Proposal

Add a read/parse surface to JsonIO symmetric to the existing write surface
and mirroring the pattern CsvIO already established:

JsonIO.parse(Class<T> klass)      // JSON records -> user type T
JsonIO.parseRows(Schema schema)   // JSON records -> Row

modeled on CsvIO.parse(Class, CSVFormat) (CsvIO.java:419) and CsvIO.parseRows(Schema, CSVFormat) (CsvIO.java:497), including their CsvIOParse result-and-error-handling pattern.

Why this is tractable

The core JSON→Row conversion already exists and is reusable:

  • JsonUtils.getJsonStringToRowFunction(Schema)
    (sdks/java/core/.../schemas/utils/JsonUtils.java:104)
  • JsonUtils.getJsonBytesToRowFunction(Schema) (line 93)
  • JsonUtils.beamSchemaFromJsonSchema(String) (line 201)

The work is primarily wiring these into a read PTransform over FileIO.match() + line reading, following the CsvIO parse structure not new parsing logic.

Testing plan

  • Unit tests mirroring CsvIO parse tests: schema validation, type conversion to both Row and custom user classes, error/failure routing.
  • Round-trip test: write JSON via JsonIO.write(), read it back via JsonIO.parseRows(), assert equality.
  • No new dependencies- JSON schema/parse machinery is already in sdks/java/core.
Issue Priority

Priority: 2 (default / most feature requests should be filed as P2)

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Lenguaje dominante
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