修复FieldsComparator比较结果不正确问题

hutool-core/src/main/java/org/dromara/hutool/core/comparator/FieldComparator.java

@@ -44,19 +44,22 @@ public class FieldComparator<T> extends FuncComparator<T> {
 	 * @param field 字段
 	 */
 	public FieldComparator(final Field field) {
-		this(true, field);
+		this(true, true, field);
 	}
 
+
 	/**
 	 * 构造
 	 *
 	 * @param nullGreater 是否{@code null}在后
+	 * @param compareSelf 在字段值相同情况下，是否比较对象本身。
+	 *                    如果此项为{@code false}，字段值比较后为0会导致对象被认为相同，可能导致被去重。
 	 * @param field       字段
 	 */
-	public FieldComparator(final boolean nullGreater, final Field field) {
-		super(nullGreater, (bean) ->
-				(Comparable<?>) FieldUtil.getFieldValue(bean,
-						Assert.notNull(field, "Field must be not null!")));
+	public FieldComparator(final boolean nullGreater, final boolean compareSelf, final Field field) {
+		super(nullGreater, compareSelf, (bean) ->
+			(Comparable<?>) FieldUtil.getFieldValue(bean,
+				Assert.notNull(field, "Field must be not null!")));
 	}
 
 	/**

hutool-core/src/main/java/org/dromara/hutool/core/comparator/FieldsComparator.java

@@ -50,7 +50,7 @@ public class FieldsComparator<T> extends NullComparator<T> {
 			for (final String fieldName : fieldNames) {
 				field = FieldUtil.getField(beanClass, fieldName);
 				Assert.notNull(field, "Field [{}] not found in Class [{}]", fieldName, beanClass.getName());
-				final int compare = new FieldComparator<>(field).compare(a, b);
+				final int compare = new FieldComparator<>(true, false, field).compare(a, b);
 				if (0 != compare) {
 					return compare;
 				}

hutool-core/src/main/java/org/dromara/hutool/core/comparator/FuncComparator.java

@@ -23,51 +23,34 @@ import java.util.function.Function;
 public class FuncComparator<T> extends NullComparator<T> {
 	private static final long serialVersionUID = 1L;
 
-	private final Function<T, Comparable<?>> func;
-
 	/**
 	 * 构造
 	 *
 	 * @param nullGreater 是否{@code null}在后
+	 * @param compareSelf 在字段值相同情况下，是否比较对象本身。
+	 *                    如果此项为{@code false}，字段值比较后为0会导致对象被认为相同，可能导致被去重。
 	 * @param func        比较项获取函数
 	 */
-	public FuncComparator(final boolean nullGreater, final Function<T, Comparable<?>> func) {
-		super(nullGreater, null);
-		this.func = func;
-	}
+	public FuncComparator(final boolean nullGreater, final boolean compareSelf, final Function<T, Comparable<?>> func) {
+		super(nullGreater, (a, b)->{
+			// 通过给定函数转换对象为指定规则的可比较对象
+			final Comparable<?> v1;
+			final Comparable<?> v2;
+			try {
+				v1 = func.apply(a);
+				v2 = func.apply(b);
+			} catch (final Exception e) {
+				throw new ComparatorException(e);
+			}
 
-	@Override
-	protected int doCompare(final T a, final T b) {
-		final Comparable<?> v1;
-		final Comparable<?> v2;
-		try {
-			v1 = func.apply(a);
-			v2 = func.apply(b);
-		} catch (final Exception e) {
-			throw new ComparatorException(e);
-		}
-
-		return compare(a, b, v1, v2);
-	}
-
-	/**
-	 * 对象及对应比较的值的综合比较<br>
-	 * 考虑到如果对象对应的比较值相同，如对象的字段值相同，则返回相同结果，此时在TreeMap等容器比较去重时会去重。<br>
-	 * 因此需要比较下对象本身以避免去重
-	 *
-	 * @param o1 对象1
-	 * @param o2 对象2
-	 * @param v1 被比较的值1
-	 * @param v2 被比较的值2
-	 * @return 比较结果
-	 */
-	@SuppressWarnings({"rawtypes", "unchecked"})
-	private int compare(final T o1, final T o2, final Comparable v1, final Comparable v2) {
-		int result = CompareUtil.compare(v1, v2, this.nullGreater);
-		if (0 == result) {
-			//避免TreeSet / TreeMap 过滤掉排序字段相同但是对象不相同的情况
-			result = CompareUtil.compare(o1, o2, this.nullGreater);
-		}
-		return result;
+			// 首先比较用户自定义的转换结果，如果为0，根据compareSelf参数决定是否比较对象本身。
+			// compareSelf为false时，主要用于多规则比较，比如多字段比较的情况
+			int result = CompareUtil.compare(v1, v2, nullGreater);
+			if (compareSelf && 0 == result) {
+				//避免TreeSet / TreeMap 过滤掉排序字段相同但是对象不相同的情况
+				result = CompareUtil.compare(a, b, nullGreater);
+			}
+			return result;
+		});
 	}
 }

hutool-core/src/main/java/org/dromara/hutool/core/comparator/PropertyComparator.java

@@ -41,6 +41,6 @@ public class PropertyComparator<T> extends FuncComparator<T> {
 	 * @param isNullGreater {@code null}值是否排在后（从小到大排序）
 	 */
 	public PropertyComparator(final String property, final boolean isNullGreater) {
-		super(isNullGreater, (bean)-> BeanUtil.getProperty(bean, property));
+		super(isNullGreater, true, (bean)-> BeanUtil.getProperty(bean, property));
 	}
 }

hutool-core/src/test/java/org/dromara/hutool/core/comparator/Issue3259Test.java

@@ -0,0 +1,56 @@
+/*
+ * Copyright (c) 2023 looly(loolly@aliyun.com)
+ * Hutool is licensed under Mulan PSL v2.
+ * You can use this software according to the terms and conditions of the Mulan PSL v2.
+ * You may obtain a copy of Mulan PSL v2 at:
+ *          http://license.coscl.org.cn/MulanPSL2
+ * THIS SOFTWARE IS PROVIDED ON AN "AS IS" BASIS, WITHOUT WARRANTIES OF ANY KIND,
+ * EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO NON-INFRINGEMENT,
+ * MERCHANTABILITY OR FIT FOR A PARTICULAR PURPOSE.
+ * See the Mulan PSL v2 for more details.
+ */
+
+package org.dromara.hutool.core.comparator;
+
+import lombok.AllArgsConstructor;
+import lombok.ToString;
+import org.dromara.hutool.core.collection.CollUtil;
+import org.dromara.hutool.core.collection.ListUtil;
+import org.dromara.hutool.core.util.RandomUtil;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Disabled;
+import org.junit.jupiter.api.Test;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class Issue3259Test {
+
+	@Test
+	public void fieldsComparatorTest() {
+		final Model x = new Model(1, 1);
+		final Model y = new Model(1, RandomUtil.randomInt(2, 100));
+
+		Assertions.assertTrue(new FieldsComparator<>(Model.class, "a", "b").compare(x, y) < 0);
+	}
+
+	@Test
+	@Disabled
+	public void sortTest() {
+		for(int i = 2; i < 5; i++) {
+			final Model x = new Model(1, 1);
+			final Model y = new Model(1, i);
+
+			List<Model> all = ListUtil.of(x, y);
+			all = CollUtil.sort(new ArrayList<>(all), new FieldsComparator<>(Model.class, "a", "b"));
+			System.out.println(all);
+		}
+	}
+
+	@AllArgsConstructor
+	@ToString
+	public static class Model {
+		public int a;
+		public int b;
+	}
+}