In many scenarios, DateTimeFormatter::format is a slower operation. For example, the following business scenarios 1. The json library gson/jackson/[fastjson2](https://github.com/alibaba/fastjson2) formats Instant/LocalDate/LocalTime/LocalDateTime/ZonedDateTim into strings. 2. In data integration scenarios, for projects like [datax](https://github.com/alibaba/datax)/[canal](https://github.com/alibaba/canal), if the input type is Date/Instant and the output type is String, formatting is required.
This PR provides format performance optimization for commonly used date patterns. ISO_INSTANT ISO_LOCAL_TIME ISO_LOCAL_DATE ISO_LOCAL_DATETIME HH:mm:ss HH:mm:ss.SSS yyyy-MM-dd yyyy-MM-dd HH:mm:ss yyyy-MM-dd'T'HH:mm:ss yyyy-MM-dd HH:mm:ss.SSS yyyy-MM-dd'T'HH:mm:ss.SSS ------------- Commit messages: - fix format LocalTime/LocalDateTime use utc - fix format ZonedDateTime & OffsetDateTime & OffsetTime use utc - sealed class CompositePrinterParser - use Pattern Matching switch - remove LocalTimePrinterParser::format support Instant - optimization support pattern 'yyyy-MM-dd HH:mm:ss.SSS' - remove digit_k - optimize DateTimeFormatter::format - fix InstantPrinterParser miss nanos - remove TimeCompositePrinterParser, fix build error - ... and 1 more: https://git.openjdk.org/jdk/compare/e0845163...564ae18b Changes: https://git.openjdk.org/jdk/pull/15722/files Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=15722&range=00 Issue: https://bugs.openjdk.org/browse/JDK-8316235 Stats: 418 lines in 6 files changed: 341 ins; 51 del; 26 mod Patch: https://git.openjdk.org/jdk/pull/15722.diff Fetch: git fetch https://git.openjdk.org/jdk.git pull/15722/head:pull/15722 PR: https://git.openjdk.org/jdk/pull/15722
