From 716cda893dbe115b5b6aa9d783e7fa23a9d5ce87 Mon Sep 17 00:00:00 2001
From: ZhouXY108 <luquanlion@outlook.com>
Date: Sat, 27 May 2023 04:09:11 +0800
Subject: [PATCH] =?UTF-8?q?=E6=B7=BB=E5=8A=A0=E5=AD=97=E7=AC=A6=E4=B8=B2?=
 =?UTF-8?q?=E2=80=9C=E8=A1=A5=E4=BD=8D=E2=80=9D=E6=96=B9=E6=B3=95=E3=80=82?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 .../zhouxy/plusone/commons/util/StrUtil.java  | 34 +++++++++++++++++++
 .../plusone/commons/util/StrUtilTests.java    | 23 +++++++++++++
 2 files changed, 57 insertions(+)
 create mode 100644 src/main/java/xyz/zhouxy/plusone/commons/util/StrUtil.java
 create mode 100644 src/test/java/xyz/zhouxy/plusone/commons/util/StrUtilTests.java

diff --git a/src/main/java/xyz/zhouxy/plusone/commons/util/StrUtil.java b/src/main/java/xyz/zhouxy/plusone/commons/util/StrUtil.java
new file mode 100644
index 0000000..ca45407
--- /dev/null
+++ b/src/main/java/xyz/zhouxy/plusone/commons/util/StrUtil.java
@@ -0,0 +1,34 @@
+package xyz.zhouxy.plusone.commons.util;
+
+import java.util.Arrays;
+
+public class StrUtil {
+
+    public static String fillBefore(String src, int minLength, char c) {
+        if (src.length() >= minLength) {
+            return src;
+        }
+        char[] result = new char[minLength];
+        Arrays.fill(result, c);
+        for (int i = 1; i <= src.length(); i++) {
+            result[minLength - i] = src.charAt(src.length() - i);
+        }
+        return String.valueOf(result);
+    }
+
+    public static String fillAfter(String src, int length, char c) {
+        if (src.length() >= length) {
+            return src;
+        }
+        char[] result = new char[length];
+        Arrays.fill(result, c);
+        for (int i = 0; i < src.length(); i++) {
+            result[i] = src.charAt(i);
+        }
+        return String.valueOf(result);
+    }
+
+    private StrUtil() {
+        throw new IllegalStateException("Utility class");
+    }
+}
diff --git a/src/test/java/xyz/zhouxy/plusone/commons/util/StrUtilTests.java b/src/test/java/xyz/zhouxy/plusone/commons/util/StrUtilTests.java
new file mode 100644
index 0000000..7ced2dc
--- /dev/null
+++ b/src/test/java/xyz/zhouxy/plusone/commons/util/StrUtilTests.java
@@ -0,0 +1,23 @@
+package xyz.zhouxy.plusone.commons.util;
+
+import org.junit.jupiter.api.Test;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+class StrUtilTests {
+
+    private static final Logger log = LoggerFactory.getLogger(StrUtilTests.class);
+
+    @Test
+    void testFillZero() {
+        char c = '=';
+        log.info(StrUtil.fillBefore("1234", 6, c));
+        log.info(StrUtil.fillBefore("12345", 6, c));
+        log.info(StrUtil.fillBefore("123456", 6, c));
+        log.info(StrUtil.fillBefore("1234567", 6, c));
+        log.info(StrUtil.fillAfter("1234", 6, c));
+        log.info(StrUtil.fillAfter("12345", 6, c));
+        log.info(StrUtil.fillAfter("123456", 6, c));
+        log.info(StrUtil.fillAfter("1234567", 6, c));
+    }
+}