Mastering Mica-Core: Essential $ Utility Methods for Java Developers

Introduction

The mica-core module encapsulates a large set of commonly used utility classes, most of which are extensions based on Spring core, to avoid reinventing the wheel and reduce bugs.

Background

Today we introduce the $ utility shortcut collection. In jquery you can use $ for various operations without remembering numerous utility classes, greatly improving development efficiency. Inspired by colleagues asking for various utility classes, we extracted these shortcuts into $ to reduce learning and development costs.

Tool Method List

Class name:

net.dreamlu.mica.core.utils.$

Assert not null

$ .requireNotNull(Object obj);

Assert not null with message

$ .requireNotNull(Object obj, String message);

Assert not null with message supplier

$ .requireNotNull(Object obj, Supplier messageSupplier);

Check if object is null

$ .isNull(Object obj);

Check if object is not null

$ .notNull(Object obj);

Convert first character to lower case

$ .firstCharToLower(String str);

Convert first character to upper case

$ .firstCharToUpper(String str);

Check if CharSequence is blank

$ .isBlank(CharSequence cs);

Check if CharSequence is not blank

$ .isNotBlank(CharSequence cs);

Check if any CharSequence is blank

$ .isAnyBlank(CharSequence... css);

Check if all CharSequences are non‑blank

$ .isNoneBlank(CharSequence... css);

Check if object is an array

$ .isArray(Object obj);

Check if object (collection, map, list, set, string, array) is empty

$ .isEmpty(Object obj);

Check if object (collection, map, list, set, string, array) is not empty

$ .isNotEmpty(Object obj);

Check if array is empty

$ .isEmpty(Object array);

Check if array is not empty

$ .isNotEmpty(Object[] array);

Format string with map parameters

$ .format(String message, Map<String, Object> params);

Log‑style format

$ .format(String message, Object... arguments);

Safe equals

$ .equalsSafe(Object o1, Object o2);

Check if array contains element

$ .contains(T[] array, T element);

Check if iterator contains element

$ .contains(Iterator<?> iterator, Object element);

Check if enumeration contains element

$ .contains(Enumeration<?> enumeration, Object element);

Immutable Set

$ .ofImmutableSet(E... es);

Immutable List

$ .ofImmutableList(E... es);

Check if string is numeric

$ .isNumeric(CharSequence cs);

String to int (default 0)

$ .toInt(String str);

String to int with default value

$ .toInt(String str, int defaultValue);

String to long (default 0)

$ .toLong(String str);

String to long with default value

$ .toLong(String str, long defaultValue);

Convert long to base‑62 string

$ .to62String(long num);

Join collection with default delimiter ','

$ .join(Collection<?> coll);

Join collection with custom delimiter

$ .join(Collection<?> coll, String delim);

Join array with default delimiter ','

$ .join(Object[] arr);

Join array with custom delimiter

$ .join(Object[] arr, String delim);

Split string

$ .split(String str, String delimiter);

Split string and trim common whitespace

$ .splitTrim(String str, String delimiter);

Simple pattern match

$ .simpleMatch(String pattern, String str);

$ .simpleMatch(String[] patterns, String str);

Generate UUID

$ .getUUID();

Escape HTML for safe filtering

$ .escapeHtml(String html);

Random number generation

$ .random(int count);

$ .random(int count, RandomType randomType);

MD5 hex

$ .md5Hex(String data);

$ .md5Hex(byte[] bytes);

SHA‑1 hex

$ .sha1Hex(String data);

$ .sha1Hex(byte[] bytes);

SHA‑224 hex

$ .sha224Hex(String data);

$ .sha224Hex(byte[] bytes);

SHA‑256 hex

$ .sha256Hex(String data);

$ .sha256Hex(byte[] bytes);

SHA‑384 hex

$ .sha384Hex(String data);

$ .sha384Hex(byte[] bytes);

SHA‑512 hex

$ .sha512Hex(String data);

$ .sha512Hex(byte[] bytes);

HMAC‑MD5 hex

$ .hmacMd5Hex(String data, String key);

$ .hmacMd5Hex(byte[] bytes, String key);

HMAC‑SHA1 hex

$ .hmacSha1Hex(String data, String key);

$ .hmacSha1Hex(byte[] bytes, String key);

HMAC‑SHA224 hex

$ .hmacSha224Hex(String data, String key);

$ .hmacSha224Hex(byte[] bytes, String key);

HMAC‑SHA256 hex

$ .hmacSha256Hex(String data, String key);

$ .hmacSha256Hex(byte[] bytes, String key);

HMAC‑SHA384 hex

$ .hmacSha384Hex(String data, String key);

$ .hmacSha384Hex(byte[] bytes, String key);

HMAC‑SHA512 hex

$ .hmacSha512Hex(String data, String key);

$ .hmacSha512Hex(byte[] bytes, String key);

Encode byte array to hex

$ .encodeHex(byte[] bytes);

Decode hex string to byte array

$ .decodeHex(String hexString);

Base64 encode

$ .encodeBase64(String value);

$ .encodeBase64(String value, Charset charset);

Base64 URL‑safe encode

$ .encodeBase64UrlSafe(String value);

$ .encodeBase64UrlSafe(String value, Charset charset);

Base64 decode

$ .decodeBase64(String value);

$ .decodeBase64(String value, Charset charset);

Base64 URL‑safe decode

$ .decodeBase64UrlSafe(String value);

$ .decodeBase64UrlSafe(String value, Charset charset);

Date‑time formatting

$ .formatDateTime(Date date);

$ .formatDateTime(TemporalAccessor temporal);

Date formatting

$ .formatDate(Date date);

$ .formatDate(TemporalAccessor temporal);

Time formatting

$ .formatTime(Date date);

$ .formatTime(TemporalAccessor temporal);

Object formatting (numbers, dates, Java 8 time)

$ .format(Object object, String pattern);

Parse string to Date

$ .parseDate(String dateStr, String pattern);

$ .parseDate(String dateStr, DateTimeFormatter formatter);

$ .parseDate(String dateStr);

Parse string to Date‑time

$ .parseDateTime(String dateStr, DateTimeFormatter formatter);

$ .parseDateTime(String dateStr);

Parse string to Time

$ .parseTime(String dateStr, DateTimeFormatter formatter);

$ .parseTime(String dateStr);

Parse with ConcurrentDateFormat

$ .parse(String dateStr, ConcurrentDateFormat format);

Time interval calculation

$ .between(Temporal startInclusive, Temporal endExclusive);

$ .between(Date startDate, Date endDate);

Object type conversion

$ .convert(Object source, Class<T> targetType);

$ .convert(Object source, TypeDescriptor sourceType, TypeDescriptor targetType);

$ .convert(Object source, TypeDescriptor targetType);

Get method parameter information

$ .getMethodParameter(Constructor<?> constructor, int parameterIndex);

$ .getMethodParameter(Method method, int parameterIndex);

Get annotation

$ .getAnnotation(AnnotatedElement annotatedElement, Class<A> annotationType);

$ .getAnnotation(Method method, Class<A> annotationType);

$ .getAnnotation(HandlerMethod handlerMethod, Class<A> annotationType);

Instantiate object

$ .newInstance(Class<?> clazz);

$ .newInstance(String clazzStr);

Get bean property (supports nested paths)

$ .getProperty(Object bean, String propertyName);

Set bean property (supports nested paths)

$ .setProperty(Object bean, String propertyName, Object value);

Shallow clone

$ .clone(Object source);

Copy object (Map or Bean)

$ .copy(Object source, Class<T> clazz);

$ .copy(Object source, Object targetBean);

Copy non‑null properties

$ .copyNonNull(Object source, Object targetBean);

Copy with type conversion

$ .copyWithConvert(Object source, Class<T> clazz);

Copy list of objects

$ .copy(Collection sourceList, Class<T> targetClazz);

Copy list with conversion

$ .copyWithConvert(Collection sourceList, Class<T> targetClazz);

Copy properties (Spring‑style)

$ .copyProperties(Object source, Class<T> clazz);

$ .copyProperties(Collection sourceList, Class<T> targetClazz);

Convert bean to map

$ .toMap(Object bean);

Convert map to bean

$ .toBean(Map<String, Object> beanMap, Class<T> valueType);