Feature: decode json to string

[alex-lx]

Convert JSON from binary format to String format. see example below

scala>  spark.sql("select * from json_test where ").show
+-----+--------------------+
|   id|         person_desc|
+-----+--------------------+
|    1|{"authors":[{"fir...|
|    2|        {"abc":null}|
|30001|"12345678\n\"世界12...|
|30002|              "1234"|
|30003|{"abc":123,"efg":...|
+-----+--------------------+

[sre-bot]

Hi contributor, thanks for your PR.

This patch needs to be approved by someone of admins. They should reply with "/ok-to-test" to accept this PR for running test automatically.

[codecov-io]

Codecov Report

❗ No coverage uploaded for pull request base (master@73f02c1). Click here to learn what that means.
The diff coverage is 4.91%.

@@            Coverage Diff            @@
##             master     #417   +/-   ##
=========================================
  Coverage          ?   54.01%           
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  Files             ?      128           
  Lines             ?     5965           
  Branches          ?      889           
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  Hits              ?     3222           
  Misses            ?     2446           
  Partials          ?      297

Impacted Files	Coverage Δ
...n/java/com/pingcap/tikv/types/DataTypeFactory.java	66% <100%> (ø)
...src/main/java/com/pingcap/tikv/types/JsonType.java	4.13% <4.13%> (ø)

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[birdstorm]

Hi, @alex-lx. Please let me express my gratitude to your brilliant patch.

I think you could add some tests concerning JSON types, you may refer to some existing tests in IssueTestSuite. I will start the review now.

[birdstorm]

Nice work, LGTM as long as corresponding tests are added. Or I could add it for you, what do you think? @alex-lx

[alex-lx]

@birdstorm, thanks for your review. I will add the test soon.

[alex-lx]

Hello, @birdstorm. Test added, Please take a look.

[sre-bot]

Hi contributor, thanks for your PR.

This patch needs to be approved by someone of admins. They should reply with "/ok-to-test" to accept this PR for running test automatically.

[birdstorm]

/ok-to-test

[birdstorm]

/run-all-tests

[birdstorm]

Please resolve test fails.

[alex-lx]

Sorry, I can‘t reproduce the failure in my environment. I think it may cause by the version of tidb. Would you mind if the test does not use judge() to compare with jdbc's result but just compare to the corresponding literal string?

[birdstorm]

@alex-lx Of course, I will handle this test failure. Thanks again for your contribution.

[birdstorm]

/run-all-tests

[birdstorm]

Test fails due to pingcap/tidb#7389

[birdstorm]

/run-all-tests