From 9b238c9429940286c6b17c2a09bd28f6ef0051b7 Mon Sep 17 00:00:00 2001 From: z3rotig4r Date: Tue, 30 Jun 2026 23:57:04 +0900 Subject: [PATCH] =?UTF-8?q?perf:=20JDBC=20=EB=B0=B0=EC=B9=98=20=EC=93=B0?= =?UTF-8?q?=EA=B8=B0=20=ED=95=AB=ED=8C=A8=EC=8A=A4=EC=9D=98=20=ED=96=89?= =?UTF-8?q?=EB=B3=84=20reflection=20=ED=95=A0=EB=8B=B9=C2=B7=EC=B2=AD?= =?UTF-8?q?=ED=81=AC=EB=B3=84=20sqlTypes=20=EC=9E=AC=EC=82=B0=EC=B6=9C=20?= =?UTF-8?q?=EC=A0=9C=EA=B1=B0?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- .../database/EgovJdbcBatchItemWriter.java | 32 +- ...vMethodMapItemPreparedStatementSetter.java | 6 +- .../EgovJdbcBatchWriteReflectionTest.java | 487 ++++++++++++++++++ 3 files changed, 521 insertions(+), 4 deletions(-) create mode 100644 Batch/org.egovframe.rte.bat.core/src/test/java/org/egovframe/rte/bat/core/item/database/EgovJdbcBatchWriteReflectionTest.java diff --git a/Batch/org.egovframe.rte.bat.core/src/main/java/org/egovframe/rte/bat/core/item/database/EgovJdbcBatchItemWriter.java b/Batch/org.egovframe.rte.bat.core/src/main/java/org/egovframe/rte/bat/core/item/database/EgovJdbcBatchItemWriter.java index f835f9d2..0e49df63 100755 --- a/Batch/org.egovframe.rte.bat.core/src/main/java/org/egovframe/rte/bat/core/item/database/EgovJdbcBatchItemWriter.java +++ b/Batch/org.egovframe.rte.bat.core/src/main/java/org/egovframe/rte/bat/core/item/database/EgovJdbcBatchItemWriter.java @@ -73,6 +73,25 @@ public class EgovJdbcBatchItemWriter implements ItemWriter, InitializingBe private EgovReflectionSupport reflector; + // params 가 고정이고 item 이 동질이면 sqlTypes 산출(getDeclaredField reflection)을 청크마다 반복할 필요가 없다. + // 최초 1회 산출 후 캐시하고, item 클래스가 달라지면(이질 item) 재산출하여 정확성을 보장한다. + // 멀티스레드 Step 에서 torn-read(이질 클래스 동시 청크 시 itemClass 와 sqlTypes 가 어긋나는 창)를 + // 막기 위해 클래스+타입배열을 불변 holder 로 묶어 단일 volatile 참조로 원자 발행하고, 소비는 지역변수로 한다. + private volatile SqlTypeCache sqlTypeCache; + + /** + * sqlTypes 캐시용 불변 holder. itemClass 와 sqlTypes 가 항상 한 쌍으로 발행된다. + */ + private static final class SqlTypeCache { + private final Class itemClass; + private final String[] sqlTypes; + + private SqlTypeCache(Class itemClass, String[] sqlTypes) { + this.itemClass = itemClass; + this.sqlTypes = sqlTypes; + } + } + /** * AssertUpdates 설정 셋팅 */ @@ -99,6 +118,8 @@ public void setItemPreparedStatementSetter(EgovItemPreparedStatementSetter pr */ public void setParams(String[] params) { this.params = params == null ? null : Arrays.asList(params).toArray(new String[params.length]); + // params 가 바뀌면 기존 sqlTypes 캐시는 stale 이므로 무효화한다. + this.sqlTypeCache = null; } /** @@ -148,8 +169,15 @@ public int[] doInPreparedStatement(PreparedStatement ps) throws SQLException, Da // Parameters 가 있으면 item, ps, params, sqlTypes,methodMap 를 파라메터로 받는 setValues call // 없으면 item, ps 를 파라메터로 받는 setValues call if (usingParameters) { - String[] sqlTypes = reflector.getSqlTypeArray(params, items.get(0)); - reflector.generateGetterMethodMap(params, items.get(0)); + T firstItem = items.get(0); + Class itemClass = firstItem.getClass(); + SqlTypeCache local = sqlTypeCache; // volatile read 1회 + if (local == null || !itemClass.equals(local.itemClass)) { + local = new SqlTypeCache(itemClass, reflector.getSqlTypeArray(params, firstItem)); + sqlTypeCache = local; // volatile publish (원자 발행) + } + String[] sqlTypes = local.sqlTypes; // 지역 소비, 공유필드 재독해 금지 + reflector.generateGetterMethodMap(params, firstItem); Map methodMap = reflector.getMethodMap(); for (T item : items) { diff --git a/Batch/org.egovframe.rte.bat.core/src/main/java/org/egovframe/rte/bat/core/item/database/support/EgovMethodMapItemPreparedStatementSetter.java b/Batch/org.egovframe.rte.bat.core/src/main/java/org/egovframe/rte/bat/core/item/database/support/EgovMethodMapItemPreparedStatementSetter.java index dcf67269..3252da56 100755 --- a/Batch/org.egovframe.rte.bat.core/src/main/java/org/egovframe/rte/bat/core/item/database/support/EgovMethodMapItemPreparedStatementSetter.java +++ b/Batch/org.egovframe.rte.bat.core/src/main/java/org/egovframe/rte/bat/core/item/database/support/EgovMethodMapItemPreparedStatementSetter.java @@ -43,13 +43,15 @@ */ public class EgovMethodMapItemPreparedStatementSetter extends EgovItemPreparedStatementSetter { + // invokeGettterMethod(item, param, methodMap) 는 인자만 사용하는 무상태 호출이므로 + // 행마다 새로 생성하지 않고 1회 생성하여 재사용한다. + private final EgovReflectionSupport reflector = new EgovReflectionSupport(); + /** * params 만큼 돌면서 sqlType별로 PreparedStatement에 자동셋팅시킴 */ @Override public void setValues(T item, PreparedStatement ps, String[] params, String[] sqlTypes, Map methodMap) throws SQLException { - EgovReflectionSupport reflector = new EgovReflectionSupport(); - for (int i = 0; i < params.length; i++) { try { if (sqlTypes[i].equals("String")) { diff --git a/Batch/org.egovframe.rte.bat.core/src/test/java/org/egovframe/rte/bat/core/item/database/EgovJdbcBatchWriteReflectionTest.java b/Batch/org.egovframe.rte.bat.core/src/test/java/org/egovframe/rte/bat/core/item/database/EgovJdbcBatchWriteReflectionTest.java new file mode 100644 index 00000000..94a5e2bd --- /dev/null +++ b/Batch/org.egovframe.rte.bat.core/src/test/java/org/egovframe/rte/bat/core/item/database/EgovJdbcBatchWriteReflectionTest.java @@ -0,0 +1,487 @@ +/* + * Copyright 2008-2024 MOIS(Ministry of the Interior and Safety). + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ +package org.egovframe.rte.bat.core.item.database; + +import org.egovframe.rte.bat.core.item.database.support.EgovMethodMapItemPreparedStatementSetter; +import org.egovframe.rte.bat.core.reflection.EgovReflectionSupport; +import org.junit.jupiter.api.Test; +import org.springframework.batch.item.Chunk; +import org.springframework.jdbc.core.JdbcTemplate; +import org.springframework.jdbc.core.PreparedStatementCallback; + +import java.lang.reflect.Field; +import java.lang.reflect.InvocationHandler; +import java.lang.reflect.Method; +import java.lang.reflect.Proxy; +import java.sql.PreparedStatement; +import java.sql.SQLException; +import java.util.ArrayList; +import java.util.List; +import java.util.Map; +import java.util.concurrent.atomic.AtomicInteger; + +import static org.junit.jupiter.api.Assertions.assertEquals; +import static org.junit.jupiter.api.Assertions.assertNotNull; +import static org.junit.jupiter.api.Assertions.assertNull; +import static org.junit.jupiter.api.Assertions.assertSame; + +/** + * JDBC 배치 쓰기 핫패스의 reflection/할당 최적화에 대한 결정적(외부 DB 없는) 검증. + * + * 
+ * - setter: EgovMethodMapItemPreparedStatementSetter 가 행마다 EgovReflectionSupport 를
+ *   재생성하지 않고 1회 생성·재사용하는지(R->1) 및 동작 보존 검증.
+ * - writer: EgovJdbcBatchItemWriter 가 sqlTypes 산출(getSqlTypeArray, getDeclaredField)을
+ *   청크마다 반복하지 않고 1회 캐시하는지(N->1, 클래스별) 및 이질 item 클래스 재산출 검증.
+ *
+ * + * @author 배치실행개발팀 + * @since 2026.06.30 + */ +class EgovJdbcBatchWriteReflectionTest { + + private static final String[] PARAMS = {"name", "age", "id", "score", "active"}; + + // --------------------------------------------------------------------- + // Test fixtures + // --------------------------------------------------------------------- + + /** sqlTypes(String, int, long, double, boolean) 분기를 커버하는 VO. */ + public static class SampleVo { + private String name; + private int age; + private long id; + private double score; + private boolean active; + + public SampleVo() { + } + + public SampleVo(String name, int age, long id, double score, boolean active) { + this.name = name; + this.age = age; + this.id = id; + this.score = score; + this.active = active; + } + + public String getName() { + return name; + } + + public int getAge() { + return age; + } + + public long getId() { + return id; + } + + public double getScore() { + return score; + } + + public boolean getActive() { + return active; + } + } + + /** 이질 item 클래스 재산출 검증용 (동일 필드 구성, 다른 클래스). */ + public static class OtherVo { + private String name; + private int age; + private long id; + private double score; + private boolean active; + + public OtherVo() { + } + + public OtherVo(String name, int age, long id, double score, boolean active) { + this.name = name; + this.age = age; + this.id = id; + this.score = score; + this.active = active; + } + + public String getName() { + return name; + } + + public int getAge() { + return age; + } + + public long getId() { + return id; + } + + public double getScore() { + return score; + } + + public boolean getActive() { + return active; + } + } + + /** getSqlTypeArray 호출 횟수를 세는 spy. (EgovReflectionSupport 미수정, 서브클래스 override) */ + static class CountingReflectionSupport extends EgovReflectionSupport { + final AtomicInteger sqlTypeArrayCalls = new AtomicInteger(); + + @Override + public String[] getSqlTypeArray(String[] params, Object item) { + sqlTypeArrayCalls.incrementAndGet(); + return super.getSqlTypeArray(params, item); + } + + int getSqlTypeArrayCalls() { + return sqlTypeArrayCalls.get(); + } + } + + /** setXxx/addBatch/executeBatch 호출을 기록하는 가짜 PreparedStatement InvocationHandler. */ + static class FakePsHandler implements InvocationHandler { + final List calls = new ArrayList<>(); // {methodName, index, value} + int batchCount = 0; + + @Override + public Object invoke(Object proxy, Method method, Object[] args) { + String name = method.getName(); + if (name.startsWith("set") && args != null && args.length >= 1 && args[0] instanceof Integer) { + calls.add(new Object[]{name, args[0], args.length > 1 ? args[1] : null}); + return null; + } + if ("addBatch".equals(name)) { + batchCount++; + return null; + } + if ("executeBatch".equals(name)) { + int[] result = new int[batchCount]; + java.util.Arrays.fill(result, 1); + return result; + } + if ("clearParameters".equals(name) || "clearBatch".equals(name)) { + return null; + } + return defaultFor(method.getReturnType()); + } + + private static Object defaultFor(Class returnType) { + if (!returnType.isPrimitive()) { + return null; + } + if (returnType == boolean.class) { + return false; + } + if (returnType == void.class) { + return null; + } + if (returnType == long.class) { + return 0L; + } + if (returnType == double.class) { + return 0d; + } + if (returnType == float.class) { + return 0f; + } + if (returnType == char.class) { + return '\0'; + } + return 0; // int, short, byte + } + } + + private static PreparedStatement newFakePs(FakePsHandler handler) { + return (PreparedStatement) Proxy.newProxyInstance( + FakePsHandler.class.getClassLoader(), + new Class[]{PreparedStatement.class}, handler); + } + + private static void assertSampleRow(List calls, int base, SampleVo vo) { + assertEquals("setString", calls.get(base)[0]); + assertEquals(1, calls.get(base)[1]); + assertEquals(vo.getName(), calls.get(base)[2]); + + assertEquals("setInt", calls.get(base + 1)[0]); + assertEquals(2, calls.get(base + 1)[1]); + assertEquals(vo.getAge(), calls.get(base + 1)[2]); + + assertEquals("setLong", calls.get(base + 2)[0]); + assertEquals(3, calls.get(base + 2)[1]); + assertEquals(vo.getId(), calls.get(base + 2)[2]); + + assertEquals("setDouble", calls.get(base + 3)[0]); + assertEquals(4, calls.get(base + 3)[1]); + assertEquals(vo.getScore(), calls.get(base + 3)[2]); + + assertEquals("setBoolean", calls.get(base + 4)[0]); + assertEquals(5, calls.get(base + 4)[1]); + assertEquals(vo.getActive(), calls.get(base + 4)[2]); + } + + // --------------------------------------------------------------------- + // Test A: setter EgovReflectionSupport 할당 hoist (R -> 1) + 동작 보존 + // --------------------------------------------------------------------- + + @Test + void setterReusesSingleReflectorAcrossRows() throws Exception { + SampleVo item = new SampleVo("kim", 30, 1001L, 88.5, true); + + EgovReflectionSupport support = new EgovReflectionSupport<>(); + support.generateGetterMethodMap(PARAMS, item); + Map methodMap = support.getMethodMap(); + String[] sqlTypes = support.getSqlTypeArray(PARAMS, item); + + EgovMethodMapItemPreparedStatementSetter setter = + new EgovMethodMapItemPreparedStatementSetter<>(); + + Field reflectorField = EgovMethodMapItemPreparedStatementSetter.class.getDeclaredField("reflector"); + reflectorField.setAccessible(true); + + Object firstReflector = null; + int rows = 5; + for (int row = 0; row < rows; row++) { + FakePsHandler handler = new FakePsHandler(); + PreparedStatement ps = newFakePs(handler); + + setter.setValues(item, ps, PARAMS, sqlTypes, methodMap); + + // R -> 1: 행마다 새로 생성하지 않고 동일 인스턴스를 재사용 + Object current = reflectorField.get(setter); + assertNotNull(current, "reflector 필드가 1회 생성되어 있어야 한다"); + if (firstReflector == null) { + firstReflector = current; + } else { + assertSame(firstReflector, current, "reflector 는 행마다 재사용되어야 한다"); + } + + // 동작 보존: ps.setXxx 호출 인자/순서가 동일 + assertEquals(PARAMS.length, handler.calls.size()); + assertSampleRow(handler.calls, 0, item); + } + } + + // --------------------------------------------------------------------- + // Test B: writer sqlTypes 캐시 (N -> 1, 클래스별) + 이질 item 재산출 + 동작 보존 + // --------------------------------------------------------------------- + + @Test + void writerCachesSqlTypesAcrossChunksAndRecomputesOnClassChange() throws Exception { + EgovJdbcBatchItemWriter writer = new EgovJdbcBatchItemWriter<>(); + writer.setSql("insert into sample (name, age, id, score, active) values (?, ?, ?, ?, ?)"); + writer.setParams(PARAMS); + writer.setItemPreparedStatementSetter(new EgovMethodMapItemPreparedStatementSetter<>()); + + final FakePsHandler[] lastHandler = new FakePsHandler[1]; + JdbcTemplate fakeTemplate = new JdbcTemplate() { + @Override + public X execute(String sql, PreparedStatementCallback action) { + FakePsHandler handler = new FakePsHandler(); + lastHandler[0] = handler; + try { + return action.doInPreparedStatement(newFakePs(handler)); + } catch (SQLException e) { + throw new RuntimeException(e); + } + } + }; + writer.setSimpleJdbcTemplate(fakeTemplate); + writer.afterPropertiesSet(); + + // afterPropertiesSet 가 생성한 reflector 를 카운팅 spy 로 교체 + CountingReflectionSupport counting = new CountingReflectionSupport<>(); + Field reflectorField = EgovJdbcBatchItemWriter.class.getDeclaredField("reflector"); + reflectorField.setAccessible(true); + reflectorField.set(writer, counting); + + // 동질 item K(=3) 청크 처리 -> getSqlTypeArray 는 1회만 (N -> 1) + SampleVo a = new SampleVo("a", 1, 10L, 1.5, true); + SampleVo b = new SampleVo("b", 2, 20L, 2.5, false); + int chunks = 3; + for (int c = 0; c < chunks; c++) { + writer.write(new Chunk<>(List.of(a, b))); + } + assertEquals(1, counting.getSqlTypeArrayCalls(), + "동질 청크 K개 처리 시 getSqlTypeArray 는 1회만 호출되어야 한다"); + + // 동작 보존: 마지막 청크의 ps 세팅이 item 별 기대 시퀀스와 일치 + assertEquals(2 * PARAMS.length, lastHandler[0].calls.size()); + assertSampleRow(lastHandler[0].calls, 0, a); + assertSampleRow(lastHandler[0].calls, PARAMS.length, b); + + // 캐시 holder 확인 (itemClass + sqlTypes 가 한 쌍으로 발행됨) + assertNotNull(sqlTypeCacheHolder(writer)); + assertEquals(SampleVo.class, cachedItemClass(writer)); + + // 이질 item 클래스 -> 재산출. (메서드맵은 클래스당 1회 생성 정책이므로 + // 사전 정책과 무관하게 캐시 무효화만 검증하기 위해 fresh spy 로 교체) + CountingReflectionSupport counting2 = new CountingReflectionSupport<>(); + reflectorField.set(writer, counting2); + + OtherVo o = new OtherVo("o", 9, 90L, 9.5, true); + writer.write(new Chunk<>(List.of(o))); + + assertEquals(1, counting2.getSqlTypeArrayCalls(), + "item 클래스가 바뀌면 sqlTypes 를 재산출해야 한다"); + assertEquals(OtherVo.class, cachedItemClass(writer)); + } + + // --------------------------------------------------------------------- + // Test C: setParams 호출 시 sqlTypes 캐시 무효화 + // --------------------------------------------------------------------- + + @Test + void setParamsInvalidatesSqlTypeCache() throws Exception { + EgovJdbcBatchItemWriter writer = new EgovJdbcBatchItemWriter<>(); + writer.setSql("insert into sample (name, age, id, score, active) values (?, ?, ?, ?, ?)"); + writer.setParams(PARAMS); + writer.setItemPreparedStatementSetter(new EgovMethodMapItemPreparedStatementSetter<>()); + writer.setSimpleJdbcTemplate(new JdbcTemplate() { + @Override + public X execute(String sql, PreparedStatementCallback action) { + try { + return action.doInPreparedStatement(newFakePs(new FakePsHandler())); + } catch (SQLException e) { + throw new RuntimeException(e); + } + } + }); + writer.afterPropertiesSet(); + + writer.write(new Chunk<>(List.of(new SampleVo("a", 1, 10L, 1.5, true)))); + assertNotNull(sqlTypeCacheHolder(writer), "최초 write 후 캐시가 채워져야 한다"); + + // params 변경 -> 캐시 무효화(stale 방지) + writer.setParams(new String[]{"name", "age"}); + assertNull(sqlTypeCacheHolder(writer), "setParams 호출 시 캐시는 무효화되어야 한다"); + } + + // --------------------------------------------------------------------- + // Test D: 멀티스레드 동시 청크에서 sqlTypes torn-read 부재 (회귀 가드) + // 서로 다른 item 클래스의 청크를 두 스레드가 인터리빙하며 write 해도, + // 각 호출이 받는 sqlTypes 는 항상 자기 item 클래스의 것과 일치해야 한다. + // --------------------------------------------------------------------- + + @Test + void concurrentChunksOfDifferentClassesNeverTearSqlTypes() throws Exception { + // 클래스별로 식별 가능한 sqlTypes 를 돌려주고, 산출-발행 사이 창을 넓히는 stub reflector. + // (실 reflection 의 methodMap/클래스당 제약과 무관하게 캐시 원자성만 격리 검증) + EgovReflectionSupport stub = new EgovReflectionSupport<>() { + @Override + public String[] getSqlTypeArray(String[] params, Object item) { + String tag = item.getClass().getSimpleName(); + Thread.yield(); // 산출-발행 사이 인터리빙 유도(torn-read 창 확대) + String[] types = new String[params.length]; + java.util.Arrays.fill(types, tag); + return types; + } + }; + + // getter 를 실제로 호출하지 않고 (item.getClass, sqlTypes) 쌍만 기록하는 setter. + final List observed = java.util.Collections.synchronizedList(new ArrayList<>()); + org.egovframe.rte.bat.core.item.database.support.EgovItemPreparedStatementSetter recordingSetter = + new org.egovframe.rte.bat.core.item.database.support.EgovItemPreparedStatementSetter<>() { + @Override + public void setValues(Object item, PreparedStatement ps, String[] params, String[] sqlTypes, Map methodMap) { + observed.add(new Object[]{item.getClass(), sqlTypes}); + } + }; + + EgovJdbcBatchItemWriter writer = new EgovJdbcBatchItemWriter<>(); + writer.setSql("insert into sample (name) values (?)"); + writer.setParams(new String[]{"name"}); + writer.setItemPreparedStatementSetter(recordingSetter); + writer.setSimpleJdbcTemplate(new JdbcTemplate() { + @Override + public X execute(String sql, PreparedStatementCallback action) { + try { + return action.doInPreparedStatement(newFakePs(new FakePsHandler())); + } catch (SQLException e) { + throw new RuntimeException(e); + } + } + }); + writer.afterPropertiesSet(); + + Field reflectorField = EgovJdbcBatchItemWriter.class.getDeclaredField("reflector"); + reflectorField.setAccessible(true); + reflectorField.set(writer, stub); + + int rounds = 300; + java.util.concurrent.CyclicBarrier barrier = new java.util.concurrent.CyclicBarrier(2); + java.util.concurrent.atomic.AtomicReference error = new java.util.concurrent.atomic.AtomicReference<>(); + + Runnable sampleWorker = worker(writer, new SampleVo("s", 1, 1L, 1.0, true), rounds, barrier, error); + Runnable otherWorker = worker(writer, new OtherVo("o", 2, 2L, 2.0, false), rounds, barrier, error); + + Thread t1 = new Thread(sampleWorker, "sample-writer"); + Thread t2 = new Thread(otherWorker, "other-writer"); + t1.start(); + t2.start(); + t1.join(); + t2.join(); + + assertNull(error.get(), "동시 write 중 예외가 없어야 한다: " + error.get()); + + // 모든 호출에서 item 클래스와 sqlTypes 가 일치(torn-read 부재). + Object[][] snapshot = observed.toArray(new Object[0][]); + assertEquals(2 * rounds, snapshot.length, "두 스레드의 모든 write 가 기록되어야 한다"); + for (Object[] pair : snapshot) { + Class itemClass = (Class) pair[0]; + String[] sqlTypes = (String[]) pair[1]; + assertEquals(itemClass.getSimpleName(), sqlTypes[0], + "item 클래스와 sqlTypes 가 어긋남(torn-read): " + itemClass.getSimpleName() + " vs " + sqlTypes[0]); + } + } + + private static Runnable worker(EgovJdbcBatchItemWriter writer, Object item, int rounds, + java.util.concurrent.CyclicBarrier barrier, + java.util.concurrent.atomic.AtomicReference error) { + return () -> { + try { + for (int i = 0; i < rounds; i++) { + barrier.await(); // 라운드마다 두 스레드를 정렬시켜 인터리빙 강제 + writer.write(new Chunk<>(List.of(item))); + } + } catch (Throwable t) { + error.compareAndSet(null, t); + } + }; + } + + // --------------------------------------------------------------------- + // 캐시 holder 리플렉션 helper + // --------------------------------------------------------------------- + + private static Object sqlTypeCacheHolder(EgovJdbcBatchItemWriter writer) throws Exception { + Field cacheField = EgovJdbcBatchItemWriter.class.getDeclaredField("sqlTypeCache"); + cacheField.setAccessible(true); + return cacheField.get(writer); + } + + private static Class cachedItemClass(EgovJdbcBatchItemWriter writer) throws Exception { + Object holder = sqlTypeCacheHolder(writer); + if (holder == null) { + return null; + } + Field itemClassField = holder.getClass().getDeclaredField("itemClass"); + itemClassField.setAccessible(true); + return (Class) itemClassField.get(holder); + } +}