From 90772979668cfca8be8dc9c80429b35ee02cd01d Mon Sep 17 00:00:00 2001
From: huangchengxing <841396397@qq.com>
Date: Tue, 30 Aug 2022 16:45:17 +0800
Subject: [PATCH] =?UTF-8?q?=E5=B0=86defaultIfNull=E6=A3=80=E9=AA=8C?=
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---
 .../java/cn/hutool/core/util/ObjUtil.java     | 26 ++++++++++++++-----
 .../java/cn/hutool/core/util/ObjUtilTest.java | 25 ++++++++++--------
 2 files changed, 34 insertions(+), 17 deletions(-)

diff --git a/hutool-core/src/main/java/cn/hutool/core/util/ObjUtil.java b/hutool-core/src/main/java/cn/hutool/core/util/ObjUtil.java
index c193bd571..18bbdc7f6 100644
--- a/hutool-core/src/main/java/cn/hutool/core/util/ObjUtil.java
+++ b/hutool-core/src/main/java/cn/hutool/core/util/ObjUtil.java
@@ -13,11 +13,7 @@ import cn.hutool.core.text.StrUtil;
 
 import java.lang.reflect.Array;
 import java.math.BigDecimal;
-import java.util.Collection;
-import java.util.Enumeration;
-import java.util.Iterator;
-import java.util.Map;
-import java.util.Objects;
+import java.util.*;
 import java.util.function.Function;
 import java.util.function.Supplier;
 
@@ -301,6 +297,7 @@ public class ObjUtil {
 	/**
 	 * 如果给定对象为{@code null} 返回默认值, 如果不为null 返回自定义handle处理后的返回值
 	 *
+	 * @param <R>          返回值类型
 	 * @param <T>          被检查对象类型
 	 * @param source       Object 类型对象
 	 * @param handler      非空时自定义的处理方法
@@ -308,13 +305,30 @@ public class ObjUtil {
 	 * @return 处理后的返回值
 	 * @since 6.0.0
 	 */
-	public static <T> T defaultIfNull(final Object source, final Function<Object, T> handler, final Supplier<? extends T> defaultSupplier) {
+	public static <T, R> R defaultIfNull(
+		final T source, final Function<? super T, ? extends R> handler, final Supplier<? extends R> defaultSupplier) {
 		if (isNotNull(source)) {
 			return handler.apply(source);
 		}
 		return defaultSupplier.get();
 	}
 
+	/**
+	 * 如果给定对象为{@code null}返回默认值, 如果不为null返回自定义handle处理后的返回值
+	 *
+	 * @param <R>          返回值类型
+	 * @param <T>          被检查对象类型
+	 * @param source       Object 类型对象
+	 * @param handler      非空时自定义的处理方法
+	 * @param defaultValue 默认为空的返回值
+	 * @return 处理后的返回值
+	 * @since 6.0.0
+	 */
+	public static <T, R> R defaultIfNull(
+		final T source, final Function<? super T, ? extends R> handler, final R defaultValue) {
+		return isNull(source) ? defaultValue : handler.apply(source);
+	}
+
 	/**
 	 * 克隆对象<br>
 	 * 如果对象实现Cloneable接口，调用其clone方法<br>
diff --git a/hutool-core/src/test/java/cn/hutool/core/util/ObjUtilTest.java b/hutool-core/src/test/java/cn/hutool/core/util/ObjUtilTest.java
index a2b34c992..2b41568ba 100644
--- a/hutool-core/src/test/java/cn/hutool/core/util/ObjUtilTest.java
+++ b/hutool-core/src/test/java/cn/hutool/core/util/ObjUtilTest.java
@@ -1,18 +1,16 @@
 package cn.hutool.core.util;
 
 import cn.hutool.core.collection.ListUtil;
-import cn.hutool.core.date.DatePattern;
-import cn.hutool.core.date.DateUtil;
 import cn.hutool.core.exceptions.CloneRuntimeException;
 import org.junit.Assert;
 import org.junit.Test;
 
 import java.math.BigDecimal;
-import java.time.Instant;
 import java.time.LocalDateTime;
 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.Map;
+import java.util.function.Function;
 
 public class ObjUtilTest {
 
@@ -99,15 +97,20 @@ public class ObjUtilTest {
 
 	@Test
 	public void defaultIfNullTest() {
-		final String dateStr = "2020-10-23 15:12:30";
-		final Instant result1 = ObjUtil.defaultIfNull(dateStr,
-				(v) -> DateUtil.parse(v.toString(), DatePattern.NORM_DATETIME_PATTERN).toInstant(), Instant::now);
-		Assert.assertNotNull(result1);
+		final Object val1 = new Object();
+		final Object val2 = new Object();
 
-		final String nullValue = null;
-		final Instant result2 = ObjUtil.defaultIfNull(nullValue,
-				(v) -> DateUtil.parse(v.toString(), DatePattern.NORM_DATETIME_PATTERN).toInstant(), Instant::now);
-		Assert.assertNotNull(result2);
+		Assert.assertSame(val1, ObjUtil.defaultIfNull(val1, () -> val2));
+		Assert.assertSame(val2, ObjUtil.defaultIfNull(null, () -> val2));
+
+		Assert.assertSame(val1, ObjUtil.defaultIfNull(val1, val2));
+		Assert.assertSame(val2, ObjUtil.defaultIfNull(null, val2));
+
+		Assert.assertSame(val1, ObjUtil.defaultIfNull(val1, Function.identity(), () -> val2));
+		Assert.assertSame(val2, ObjUtil.defaultIfNull(null, Function.identity(), () -> val2));
+
+		Assert.assertSame(val1, ObjUtil.defaultIfNull(val1, Function.identity(), val2));
+		Assert.assertSame(val2, ObjUtil.defaultIfNull(null, Function.identity(), val2));
 	}
 
 	@Test