Add raw java example for `spi-based-sharding-algorithm-example`

[lushaorong]

Fixes #15717.

Changes proposed in this pull request:

• Add raw java example for spi-based-sharding-algorithm-example

[codecov-commenter]

Codecov Report

Merging #19718 (dc5341c) into master (a696de8) will increase coverage by 0.17%. The diff coverage is n/a.

@@             Coverage Diff              @@
##             master   #19718      +/-   ##
============================================
+ Coverage     60.02%   60.19%   +0.17%     
- Complexity     2389     2423      +34     
============================================
  Files          3847     3875      +28     
  Lines         54853    54997     +144     
  Branches       7664     7695      +31     
============================================
+ Hits          32927    33107     +180     
+ Misses        19101    19047      -54     
- Partials       2825     2843      +18     

Impacted Files	Coverage Δ
...ases/domain/statement/CommonStatementTestCase.java	0.00% <0.00%> (-100.00%)	:arrow_down:
...ion/optimizer/context/OptimizerContextFactory.java	0.00% <0.00%> (-100.00%)	:arrow_down:
.../context/parser/OptimizerParserContextFactory.java	0.00% <0.00%> (-100.00%)	:arrow_down:
.../infra/yaml/config/pojo/YamlRootConfiguration.java	0.00% <0.00%> (-80.00%)	:arrow_down:
...resql/PostgreSQLSessionVariableHandlerFactory.java	50.00% <0.00%> (-25.00%)	:arrow_down:
...ontext/planner/OptimizerPlannerContextFactory.java	76.19% <0.00%> (-23.81%)	:arrow_down:
...dmin/mysql/MySQLSessionVariableHandlerFactory.java	75.00% <0.00%> (-12.50%)	:arrow_down:
...re/sharding/merge/dql/ShardingDQLResultMerger.java	76.74% <0.00%> (-9.31%)	:arrow_down:
...tgresql/executor/PostgreSQLSetCharsetExecutor.java	10.00% <0.00%> (-8.19%)	:arrow_down:
...end/communication/DatabaseCommunicationEngine.java	23.80% <0.00%> (-3.47%)	:arrow_down:
... and 365 more

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[RaigorJiang]

Hi @lushaorong CI failed because the master branch has been refactored, you need to merge the latest master code in your own branch and push again, thank you!