1. 删除 DateTimeTools 中的格式化器的缓存，应由调用方执行负责维护；

2. 新增 toYearString 和 toMonthString 方法。

src/main/java/xyz/zhouxy/plusone/commons/sql/JdbcSql.java

@@ -18,6 +18,8 @@ package xyz.zhouxy.plusone.commons.sql;
 
 import java.util.Collection;
 
+import xyz.zhouxy.plusone.commons.util.StringTools;
+
 public class JdbcSql extends SQL<JdbcSql> {
 
     JdbcSql() {
@@ -33,40 +35,38 @@ public class JdbcSql extends SQL<JdbcSql> {
         return this;
     }
 
-    public static String IN(String col, Collection<?> c) {
+    public static String IN(String col, Collection<?> c) { // NOSONAR
         return IN(col, c.size());
     }
 
-    public static <T> String IN(String col, T[] c) {
+    public static <T> String IN(String col, T[] c) { // NOSONAR
         return IN(col, c.length);
     }
 
-    private static String IN(String col, int length) {
-        return col + " IN (" + String.valueOf(buildQuestionsList(length)) + ')';
+    private static String IN(String col, int length) { // NOSONAR
+        if (length == 0) {
+            return "false";
+        }
+        return col + " IN (" + buildQuestionsList(length) + ')';
     }
 
-    public static String NOT_IN(String col, Collection<?> c) {
+    public static String NOT_IN(String col, Collection<?> c) { // NOSONAR
         return NOT_IN(col, c.size());
     }
 
-    public static <T> String NOT_IN(String col, T[] c) {
+    public static <T> String NOT_IN(String col, T[] c) { // NOSONAR
         return NOT_IN(col, c.length);
     }
 
-    private static String NOT_IN(String col, int length) {
-        return col + " NOT IN (" + String.valueOf(buildQuestionsList(length)) + ')';
+    private static String NOT_IN(String col, int length) { // NOSONAR
+        if (length == 0) {
+            return "true";
+        }
+        return col + " NOT IN (" + buildQuestionsList(length) + ')';
     }
 
-    private static char[] buildQuestionsList(int times) {
-        char[] arr = new char[times * 3 - 2];
-        int i = 0;
-        for (int t = 1; t <= times; t++) {
-            arr[i++] = '?';
-            if (t < times) {
-                arr[i++] = ',';
-                arr[i++] = ' ';
-            }
-        }
-        return arr;
+    private static String buildQuestionsList(int times) {
+        final int length = times <= 0 ? 0 : (times * 3 - 2);
+        return StringTools.repeat("?, ", times, length);
     }
 }

src/main/java/xyz/zhouxy/plusone/commons/sql/MyBatisSql.java

@@ -41,11 +41,11 @@ public class MyBatisSql extends SQL<MyBatisSql> {
         return this;
     }
 
-    public static String IN(String col, String paramName) {
+    public static String IN(String col, String paramName) { // NOSONAR
         return " " + col + " IN" + buildForeach(col, paramName);
     }
 
-    public static String NOT_IN(String col, String paramName) {
+    public static String NOT_IN(String col, String paramName) { // NOSONAR
         return col + " NOT IN" + buildForeach(col, paramName);
     }
 

src/main/java/xyz/zhouxy/plusone/commons/sql/SQL.java

@@ -34,14 +34,14 @@ public abstract class SQL<T> extends AbstractSQL<T> {
         return new MyBatisSql(withScript);
     }
 
-    public T WHERE(boolean condition, String sqlCondition) {
+    public T WHERE(boolean condition, String sqlCondition) { // NOSONAR
         if (condition) {
             return WHERE(sqlCondition);
         }
         return getSelf();
     }
 
-    public T WHERE(boolean condition, String ifSqlCondition, String elseSqlCondition) {
+    public T WHERE(boolean condition, String ifSqlCondition, String elseSqlCondition) { // NOSONAR
         return WHERE(condition ? ifSqlCondition : elseSqlCondition);
     }
 }

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

@@ -21,19 +21,17 @@ import java.time.LocalDate;
 import java.time.LocalDateTime;
 import java.time.LocalTime;
 import java.time.Month;
+import java.time.Year;
 import java.time.YearMonth;
 import java.time.ZoneId;
 import java.time.ZonedDateTime;
-import java.time.format.DateTimeFormatter;
+import java.time.chrono.IsoChronology;
 import java.util.Calendar;
 import java.util.Date;
 import java.util.TimeZone;
 
-import javax.annotation.Nonnull;
-
-import com.google.common.cache.CacheBuilder;
-import com.google.common.cache.CacheLoader;
-import com.google.common.cache.LoadingCache;
+import com.google.common.base.Strings;
+import com.google.common.collect.Range;
 
 import xyz.zhouxy.plusone.commons.time.Quarter;
 import xyz.zhouxy.plusone.commons.time.YearQuarter;
@@ -45,89 +43,32 @@ import xyz.zhouxy.plusone.commons.time.YearQuarter;
  */
 public class DateTimeTools {
 
-    /**
-     * 缓存时间格式化器
-     */
-    private static final LoadingCache<String, DateTimeFormatter> DATE_TIME_FORMATTER_CACHE = CacheBuilder.newBuilder()
-            .maximumSize(20)
-            .build(new CacheLoader<String, DateTimeFormatter>() {
-                @Override
-                public DateTimeFormatter load(@Nonnull String pattern) throws Exception {
-                    return DateTimeFormatter.ofPattern(pattern);
-                }
-            });
-
-    /**
-     * 获取时间格式化器
-     *
-     * @param pattern 时间格式
-     * @return 时间格式化器
-     */
-    public static DateTimeFormatter getDateTimeFormatter(String pattern) {
-        return DATE_TIME_FORMATTER_CACHE.getUnchecked(pattern);
-    }
-
     // #region - toString
 
-    /**
-     * 将日期时间转换为指定格式的字符串
-     *
-     * @param pattern  时间格式
-     * @param dateTime 日期时间
-     * @return 格式化的字符串
-     */
-    public static String toString(String pattern, ZonedDateTime dateTime) {
-        return getDateTimeFormatter(pattern).format(dateTime);
+    public static String toYearString(int year) {
+        return Integer.toString(year);
     }
 
-    /**
-     * 将时间戳转换为指定格式的字符串，使用系统默认时区
-     *
-     * @param pattern 时间格式
-     * @param instant 时间戳
-     * @return 格式化的字符串
-     */
-    public static String toString(String pattern, Instant instant) {
-        ZonedDateTime dateTime = instant.atZone(ZoneId.systemDefault());
-        return toString(pattern, dateTime);
+    public static String toYearString(Year year) {
+        return year.toString();
     }
 
-    /**
-     * 将时间戳转换为指定格式的字符串，使用指定时区
-     *
-     * @param pattern 时间格式
-     * @param instant 时间戳
-     * @param zone    时区
-     * @return 格式化的字符串
-     */
-    public static String toString(String pattern, Instant instant, ZoneId zone) {
-        ZonedDateTime dateTime = instant.atZone(zone);
-        return toString(pattern, dateTime);
+    public static String toMonthString(int monthValue) {
+        return Strings.padStart(Integer.toString(monthValue), 2, '0');
     }
 
-    // #endregion
-
-    // #region - nowStr
-
-    /**
-     * 指定格式，返回当前时间戳对应的字符串
-     *
-     * @param pattern 时间格式
-     * @return 格式化的字符串
-     */
-    public static String nowStr(String pattern) {
-        return toString(pattern, ZonedDateTime.now());
+    public static String toMonthString(int monthValue, boolean padStart) {
+        return padStart ? toMonthString(monthValue) : Integer.toString(monthValue);
     }
 
-    /**
-     * 指定格式，返回当前时间戳对应的字符串，使用指定时区
-     *
-     * @param pattern 时间格式
-     * @param zone    时区
-     * @return 格式化的字符串
-     */
-    public static String nowStr(String pattern, ZoneId zone) {
-        return toString(pattern, Instant.now().atZone(zone));
+    public static String toMonthString(Month month) {
+        final int monthValue = month.getValue();
+        return Strings.padStart(Integer.toString(monthValue), 2, '0');
+    }
+
+    public static String toMonthString(Month month, boolean padStart) {
+        final int monthValue = month.getValue();
+        return padStart ? toMonthString(month) : Integer.toString(monthValue);
     }
 
     // #endregion
@@ -708,6 +649,42 @@ public class DateTimeTools {
 
     // #endregion
 
+    // ================================
+    // #region - others
+    // ================================
+
+    public static LocalDate startDateOfYear(int year) {
+        return LocalDate.ofYearDay(year, 1);
+    }
+
+    public static LocalDate endDateOfYear(int year) {
+        return LocalDate.of(year, 12, 31);
+    }
+
+    public static LocalDateTime startOfNextDate(LocalDate date) {
+        return date.plusDays(1L).atStartOfDay();
+    }
+
+    public static ZonedDateTime startOfNextDate(LocalDate date, ZoneId zone) {
+        return date.plusDays(1L).atStartOfDay(zone);
+    }
+
+    public static Range<LocalDateTime> toDateTimeRange(LocalDate date) {
+        return Range.closedOpen(date.atStartOfDay(), startOfNextDate(date));
+    }
+
+    public static Range<ZonedDateTime> toDateTimeRange(LocalDate date, ZoneId zone) {
+        return Range.closedOpen(date.atStartOfDay(zone), startOfNextDate(date, zone));
+    }
+
+    public static boolean isLeapYear(int year) {
+        return IsoChronology.INSTANCE.isLeapYear(year);
+    }
+
+    // ================================
+    // #endregion - others
+    // ================================
+
     /**
      * 私有构造方法，明确标识该常量类的作用。
      */

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

@@ -20,6 +20,7 @@ import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import java.time.Instant;
 import java.time.LocalDateTime;
+import java.time.Month;
 import java.time.ZoneId;
 import java.time.ZonedDateTime;
 import java.time.format.DateTimeFormatter;
@@ -32,13 +33,6 @@ class DateTimeToolsTests {
 
     private static final Logger log = LoggerFactory.getLogger(DateTimeToolsTests.class);
 
-    @Test
-    void testLocalNowStr() {
-        String nowStr = DateTimeTools.nowStr("yyyy/MM/dd HH:mm:ss.SSS");
-        log.info(nowStr);
-        assertEquals(23, nowStr.length());
-    }
-
     @Test
     void testToJoda() {
         LocalDateTime dt = LocalDateTime.of(2008, 8, 8, 20, 18, 59, 108000000);
@@ -55,7 +49,8 @@ class DateTimeToolsTests {
     void testToInstant() {
         ZonedDateTime dt = ZonedDateTime.of(2008, 1, 8, 10, 23, 50, 108000000, ZoneId.systemDefault());
         Instant instant = DateTimeTools.toInstant(dt.toInstant().toEpochMilli());
-        String str = DateTimeTools.toString("yy-M-d HH:mm:ss.SSS", instant);
+        DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yy-M-d HH:mm:ss.SSS");
+        String str = formatter.format(instant.atZone(ZoneId.systemDefault()));
         log.info(str);
         assertEquals("08-1-8 10:23:50.108", str);
     }
@@ -107,4 +102,11 @@ class DateTimeToolsTests {
         log.info("{}", formatter);
         log.info("{}", formatter2);
     }
+
+    @Test
+    void testToString() {
+        assertEquals("04", DateTimeTools.toMonthString(Month.APRIL));
+        assertEquals("04", DateTimeTools.toMonthString(Month.APRIL, true));
+        assertEquals("4", DateTimeTools.toMonthString(Month.APRIL, false));
+    }
 }