StringUtils
叫StringUtils或StringUtil的實在是太多了，首先就是大名鼎鼎的org.apache.commons.lang3.StringUtils，提供了如isEmpty、isNotEmpty、isBlank饱亮、isNotBlank等等的常用字符串判空方法，非常的實用；另外一個比較常見的提供者就是org.springframework.util.StringUtils沫屡，我們在看Spring的源碼的時候經(jīng)常會見到，但其實他用的是自己寫的工具類撮珠，并不是apache提供的沮脖，這里面也提供了許多類似的方法，如isEmpty芯急、hasLength勺届、hasText等，如果你的系統(tǒng)采用的是Spring框架的話娶耍，那么可以直接使用這個工具類免姿。
BeanUtils
org.springframework.beans.BeanUtils
JavaBeans的靜態(tài)方法：用于實例化bean、檢查bean屬性類型榕酒、復制bean屬性等胚膊。
避免用Apache Beanutils進行屬性的copy。
說明：Apache BeanUtils性能較差想鹰，可以使用其他方案比如Spring BeanUtils, Cglib BeanCopier
-- 阿里巴巴Java開發(fā)規(guī)范
public static void copyProperties(Object source, Object target) throws BeansException
StandardCharsets
java.nio.charset.StandardCharsets
如果不想直接寫"UTF-8"這個字符串紊婉，那么可以直接用StandardCharsets.UTF_8.name()。
支持的Charset：
/**
* Seven-bit ASCII, a.k.a. ISO646-US, a.k.a. the Basic Latin block of the
* Unicode character set
*/
public static final Charset US_ASCII = Charset.forName("US-ASCII");
/**
* ISO Latin Alphabet No. 1, a.k.a. ISO-LATIN-1
*/
public static final Charset ISO_8859_1 = Charset.forName("ISO-8859-1");
/**
* Eight-bit UCS Transformation Format
*/
public static final Charset UTF_8 = Charset.forName("UTF-8");
/**
* Sixteen-bit UCS Transformation Format, big-endian byte order
*/
public static final Charset UTF_16BE = Charset.forName("UTF-16BE");
/**
* Sixteen-bit UCS Transformation Format, little-endian byte order
*/
public static final Charset UTF_16LE = Charset.forName("UTF-16LE");
/**
* Sixteen-bit UCS Transformation Format, byte order identified by an
* optional byte-order mark
*/
public static final Charset UTF_16 = Charset.forName("UTF-16");
CharEncoding
org.apache.commons.lang3.CharEncoding
里面定義了許多常用的編碼格式
如 ISO-8859-1辑舷、US-ASCII喻犁、UTF-8
/**
* @deprecated Please use {@link Charset#isSupported(String)} instead, although be aware that {@code null}
* values are not accepted by that method and an {@link IllegalCharsetNameException} may be thrown.
*/
boolean isSupported(final String name)
新版的CharEncoding已經(jīng)被標記為@Deprecated，因為JDK7已經(jīng)自帶了java.nio.charset.StandardCharsets惩妇，我們可以直接使用JDK自帶的StandardCharsets株汉。
HtmlUtils
org.springframework.web.util.HtmlUtils
//對HTML里的標簽進行轉(zhuǎn)義
public static String htmlEscape(String input, String encoding)
另見org.springframework.web.util.JavaScriptUtils
ObjectUtils
org.springframework.util.ObjectUtils
// Determine whether the given object is empty
public static boolean isEmpty(@Nullable Object obj)
// Determine whether the given array is empty
public static boolean isEmpty(@Nullable Object[] array) {
// Return whether the given throwable is a checked exception
public static boolean isCheckedException(Throwable ex)
// Determine whether the given object is an array
public static boolean isArray(@Nullable Object obj)
FileUtils
org.apache.commons.io.FileUtils
文件復制，文件轉(zhuǎn)換等（同org.springframework.util.FileCopyUtils）
public static void copyFile(final File srcFile, final File destFile)
public static void copyDirectoryToDirectory(final File srcDir, final File destDir)
public static void touch(final File file) throws IOException
public static void deleteDirectory(final File directory)
public static String readFileToString(final File file, final Charset encoding) throws IOException
public static void writeStringToFile(final File file, final String data, final Charset encoding,
final boolean append) throws IOException
public static void moveFile(final File srcFile, final File destFile) throws IOException
// Returns the size of the specified file or directory.
public static long sizeOf(final File file)
// Deletes a file. If file is a directory, delete it and all sub-directories.
public static void forceDelete(final File file) throws IOException
// Determines whether the specified file is a Symbolic Link rather than an actual file.
public static boolean isSymlink(final File file) throws IOException
FilenameUtils
org.apache.commons.io.FilenameUtils
獲取文件名歌殃、擴展名等
// 獲取文件名乔妈，如a/b/c.txt --> c.txt
public static String getName(final String filename)
// 獲取文件名的擴展名，如foo.txt --> "txt"
// a/b/c.jpg --> "jpg"
// a/b.txt/c --> ""
// a/b/c --> ""
public static String getExtension(final String filename)
// 去除擴展名
public static String removeExtension(final String filename)
IOUtils
org.apache.commons.io.IOUtils
通用IO流操作實用工具氓皱。
public static String toString(final InputStream input, final Charset encoding)
public static void write(final String data, final OutputStream output, final Charset encoding) throws IOException
DigestUtils
org.springframework.util.DigestUtils
計算摘要的各種方法路召。推薦使用Apache Commons Codec用于更全面的摘要實用程序套件勃刨。
