feat: 新增字符串脱敏方法 StringTools#desensitize

src/main/java/xyz/zhouxy/plusone/commons/util/StringTools.java

@@ -184,6 +184,42 @@ public class StringTools {
         return true;
     }
 
+    /**
+     * 脱敏
+     *
+     * @param src          原字符串
+     * @param front        前面保留的字符数
+     * @param end          后面保留的字符数
+     * @return 脱敏结果
+     * @since 1.1.0
+     */
+    public static String desensitize(@Nullable final String src, int front, int end) {
+        return desensitize(src, '*', front, end);
+    }
+
+    /**
+     * 脱敏
+     *
+     * @param src          原字符串
+     * @param replacedChar 用于替换的字符
+     * @param front        前面保留的字符数
+     * @param end          后面保留的字符数
+     * @return 脱敏结果
+     * @since 1.1.0
+     */
+    public static String desensitize(@Nullable final String src, char replacedChar, int front, int end) {
+        if (src == null || src.isEmpty()) {
+            return EMPTY_STRING;
+        }
+        AssertTools.checkArgument(front >= 0 && end >= 0);
+        AssertTools.checkArgument((front + end) <= src.length(), "需要截取的长度不能大于原字符串长度");
+        final char[] charArray = src.toCharArray();
+        for (int i = front; i < charArray.length - end; i++) {
+            charArray[i] = replacedChar;
+        }
+        return String.valueOf(charArray);
+    }
+
     private StringTools() {
         throw new IllegalStateException("Utility class");
     }

src/test/java/xyz/zhouxy/plusone/commons/util/StringToolsTests.java

@@ -26,6 +26,7 @@ import static org.junit.jupiter.api.Assertions.assertTrue;
 import java.lang.reflect.Constructor;
 import java.util.Arrays;
 
+import org.junit.jupiter.api.Assertions;
 import org.junit.jupiter.api.Test;
 
 @SuppressWarnings("null")
@@ -184,7 +185,7 @@ class StringToolsTests {
     // #region - isURL
     // ================================
 
-        /**
+    /**
      * TC1: 验证标准HTTP协议URL
      */
     @Test
@@ -298,6 +299,77 @@ class StringToolsTests {
     // #endregion - repeat
     // ================================
 
+    // ================================
+    // #region - desensitize
+    // ================================
+
+    @Test
+    public void desensitize_NullInput_ReturnsEmptyString() {
+        String result = StringTools.desensitize(null, '#', 2, 2);
+        Assertions.assertEquals("", result);
+    }
+
+    @Test
+    public void desensitize_EmptyString_ReturnsEmptyString() {
+        String result = StringTools.desensitize("", '#', 2, 2);
+        Assertions.assertEquals("", result);
+    }
+
+    @Test
+    public void desensitize_NegativeFront_ThrowsException() {
+        Assertions.assertThrows(IllegalArgumentException.class, () -> {
+            StringTools.desensitize("123456", '#', -1, 2);
+        });
+    }
+
+    @Test
+    public void desensitize_NegativeEnd_ThrowsException() {
+        Assertions.assertThrows(IllegalArgumentException.class, () -> {
+            StringTools.desensitize("123456", '#', 2, -1);
+        });
+    }
+
+    @Test
+    public void desensitize_FrontPlusEndExceedsLength_ThrowsException() {
+        Assertions.assertThrows(IllegalArgumentException.class, () -> {
+            StringTools.desensitize("123456", '#', 3, 4);
+        });
+    }
+
+    @Test
+    public void desensitize_ValidInput_ReturnsDesensitizedString() {
+        String result = StringTools.desensitize("123456", '#', 2, 2);
+        Assertions.assertEquals("12##56", result);
+    }
+
+    @Test
+    public void desensitize_FrontZero_ReturnsDesensitizedString() {
+        String result = StringTools.desensitize("123456", '#', 0, 2);
+        Assertions.assertEquals("####56", result);
+    }
+
+    @Test
+    public void desensitize_EndZero_ReturnsDesensitizedString() {
+        String result = StringTools.desensitize("123456", '#', 2, 0);
+        Assertions.assertEquals("12####", result);
+    }
+
+    @Test
+    public void desensitize_FrontAndEndZero_ReturnsDesensitizedString() {
+        String result = StringTools.desensitize("123456", '#', 0, 0);
+        Assertions.assertEquals("######", result);
+    }
+
+    @Test
+    public void desensitize_ValidInput_DefaultReplacedChar_ReturnsDesensitizedString() {
+        String result = StringTools.desensitize("123456", 2, 2);
+        Assertions.assertEquals("12**56", result);
+    }
+
+    // ================================
+    // #endregion - desensitize
+    // ================================
+
     @Test
     void test_constructor_isNotAccessible_ThrowsIllegalStateException() {
         Constructor<?>[] constructors = StringTools.class.getDeclaredConstructors();