判空、判等、转码的StringUtil

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• StringUtil类

StringUtil类

import java.io.UnsupportedEncodingException;

/**
 * 字符串工具
 */
public class StringUtil {

	/**
	 * 比较两个字符串（大小写敏感）。
	 * <pre>
	 * StringUtil.equals(null, null)   = true
	 * StringUtil.equals(null, "abc")  = false
	 * StringUtil.equals("abc", null)  = false
	 * StringUtil.equals("abc", "abc") = true
	 * StringUtil.equals("abc", "ABC") = false
	 * </pre>
	 *
	 * @param str1 要比较的字符串1
	 * @param str2 要比较的字符串2
	 *
	 * @return 如果两个字符串相同，或者都是<code>null</code>，则返回<code>true</code>
	 */
	public static boolean equals(String str1, String str2) {
		if (str1 == null) {
			return str2 == null;
		}

		return str1.equals(str2);
	}
	// Empty checks
	//-----------------------------------------------------------------------
	/**
	 * <p>Checks if a CharSequence is empty ("") or null.</p>
	 * <pre>
	 * StringUtils.isEmpty(null)      = true
	 * StringUtils.isEmpty("")        = true
	 * StringUtils.isEmpty(" ")       = false
	 * StringUtils.isEmpty("bob")     = false
	 * StringUtils.isEmpty("  bob  ") = false
	 * </pre>
	 * @param cs  the CharSequence to check, may be null
	 * @return {@code true} if the CharSequence is empty or null
	 */
	public static boolean isEmpty(CharSequence cs) {
		return cs == null || cs.length() == 0;
	}

	/**
	 * <p>Checks if a CharSequence is not empty ("") and not null.</p>
	 *
	 * <pre>
	 * StringUtils.isNotEmpty(null)      = false
	 * StringUtils.isNotEmpty("")        = false
	 * StringUtils.isNotEmpty(" ")       = true
	 * StringUtils.isNotEmpty("bob")     = true
	 * StringUtils.isNotEmpty("  bob  ") = true
	 * </pre>
	 *
	 * @param cs  the CharSequence to check, may be null
	 * @return {@code true} if the CharSequence is not empty and not null
	 */
	public static boolean isNotEmpty(CharSequence cs) {
		return !StringUtils.isEmpty(cs);
	}

	/**
	 * <p>Checks if a CharSequence is whitespace, empty ("") or null.</p>
	 *
	 * <pre>
	 * StringUtils.isBlank(null)      = true
	 * StringUtils.isBlank("")        = true
	 * StringUtils.isBlank(" ")       = true
	 * StringUtils.isBlank("bob")     = false
	 * StringUtils.isBlank("  bob  ") = false
	 * </pre>
	 * @param cs  the CharSequence to check, may be null
	 * @return {@code true} if the CharSequence is null, empty or whitespace
	 * @since 2.0
	 */
	public static boolean isBlank(CharSequence cs) {
		int strLen;
		if (cs == null || (strLen = cs.length()) == 0) {
			return true;
		}
		for (int i = 0; i < strLen; i++) {
			if (Character.isWhitespace(cs.charAt(i)) == false) {
				return false;
			}
		}
		return true;
	}

	/**
	 * <p>Checks if a CharSequence is not empty (""), not null and not whitespace only.</p>
	 *
	 * <pre>
	 * StringUtils.isNotBlank(null)      = false
	 * StringUtils.isNotBlank("")        = false
	 * StringUtils.isNotBlank(" ")       = false
	 * StringUtils.isNotBlank("bob")     = true
	 * StringUtils.isNotBlank("  bob  ") = true
	 * </pre>
	 * @param cs  the CharSequence to check, may be null
	 * @return {@code true} if the CharSequence is
	 *  not empty and not null and not whitespace
	 */
	public static boolean isNotBlank(CharSequence cs) {
		return !StringUtils.isBlank(cs);
	}

	/**
	 * @param content 需要加密串
	 * @param charset 字符集
	 * @return 加密后的字节数组
	 */
	public static byte[] getContentBytes(String content, String charset) {
		if (StringUtils.isEmpty(charset)) {
			return content.getBytes();
		}
		try {
			return content.getBytes(charset);
		} catch (UnsupportedEncodingException e) {
			throw new RuntimeException("转码过程中出现错误,指定的编码集不对,您目前指定的编码集是:" + charset);
		}
	}

}