新：新增条件组，用于处理复杂的where条件

hutool-db/src/main/java/cn/hutool/db/sql/ConditionGroup.java

@@ -0,0 +1,51 @@
+package cn.hutool.db.sql;
+
+import cn.hutool.core.util.ArrayUtil;
+import cn.hutool.core.util.StrUtil;
+
+import java.util.List;
+
+/**
+ * 条件组<br/>
+ * 用于构建复杂where条件
+ *
+ * @author tjh
+ */
+public class ConditionGroup extends Condition{
+	/**
+	 * 条件列表
+	 */
+	private Condition[] conditions;
+
+	/**
+	 * 追加条件
+	 *
+	 * @param conditions 条件列表
+	 */
+	public void addConditions(Condition... conditions) {
+		if(null == this.conditions) {
+			this.conditions = conditions;
+		} else {
+			this.conditions = ArrayUtil.addAll(this.conditions, conditions);
+		}
+	}
+
+	/**
+	 * 将条件组转换为条件字符串，使用括号包裹，并回填占位符对应的参数值
+	 *
+	 * @param paramValues 参数列表，用于回填占位符对应参数值
+	 * @return 条件字符串
+	 */
+	@Override
+	public String toString(List<Object> paramValues) {
+		if (ArrayUtil.isEmpty(conditions)) return StrUtil.EMPTY;
+
+		final StringBuilder conditionStrBuilder = StrUtil.builder();
+		conditionStrBuilder.append("(");
+		// 将组内的条件构造为SQL，因为toString，会进行递归，处理所有的条件组
+		conditionStrBuilder.append(ConditionBuilder.of(this.conditions).build(paramValues));
+		conditionStrBuilder.append(")");
+
+		return conditionStrBuilder.toString();
+	}
+}

hutool-db/src/test/java/cn/hutool/db/sql/ConditionGroupTest.java

@@ -0,0 +1,26 @@
+package cn.hutool.db.sql;
+
+import org.junit.Test;
+
+public class ConditionGroupTest {
+	@Test
+	public void ConditionGroupToStringTest() {
+		Condition condition1 = new Condition("a", "A");
+		Condition condition2 = new Condition("b", "B");
+		condition2.setLinkOperator(LogicalOperator.OR);
+		Condition condition3 = new Condition("c", "C");
+		Condition condition4 = new Condition("d", "D");
+
+		ConditionGroup cg = new ConditionGroup();
+		cg.addConditions(condition1, condition2);
+
+		// 条件组嵌套情况
+		ConditionGroup cg2 = new ConditionGroup();
+		cg2.addConditions(cg, condition3);
+
+		final ConditionBuilder conditionBuilder = ConditionBuilder.of(cg2, condition4);
+
+		System.out.println(conditionBuilder.build());
+		System.out.println(conditionBuilder.getParamValues());
+	}
+}