feat(core): 新增字符串工具类

continew-starter-core/src/main/java/top/continew/starter/core/util/StrUtils.java

@@ -0,0 +1,46 @@
+/*
+ * Copyright (c) 2022-present Charles7c Authors. All Rights Reserved.
+ * <p>
+ * Licensed under the GNU LESSER GENERAL PUBLIC LICENSE 3.0;
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * <p>
+ * http://www.gnu.org/licenses/lgpl.html
+ * <p>
+ * 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 top.continew.starter.core.util;
+
+import cn.hutool.core.text.CharSequenceUtil;
+
+import java.util.function.Function;
+
+/**
+ * 字符串工具类
+ *
+ * @author Charles7c
+ * @since 2.0.1
+ */
+public class StrUtils {
+
+    private StrUtils() {
+    }
+
+    /**
+     * 如果字符串是{@code null}或者&quot;&quot;或者空白，则返回指定默认字符串，否则针对字符串处理后返回
+     *
+     * @param str          要转换的字符串
+     * @param defaultValue 默认值
+     * @param mapping      针对字符串的转换方法
+     * @return 转换后的字符串或指定的默认字符串
+     * @since 2.0.1
+     */
+    public static <T> T blankToDefault(CharSequence str, T defaultValue, Function<String, T> mapping) {
+        return CharSequenceUtil.isBlank(str) ? defaultValue : mapping.apply(str.toString());
+    }
+}