package cn.palmte.work.utils; import java.io.UnsupportedEncodingException; import java.security.SecureRandom; import java.util.Random; /** * Created by tracy on 2018/4/17. */ public class StrKit { public static final String DEFAULT_ENCODING = "UTF-8"; static SecureRandom r = new SecureRandom(); //static Random r = new Random(); /** * 首字母变小写 */ public static String firstCharToLowerCase(String str) { char firstChar = str.charAt(0); if (firstChar >= 'A' && firstChar <= 'Z') { char[] arr = str.toCharArray(); arr[0] += ('a' - 'A'); return new String(arr); } return str; } /** * 首字母变大写 */ public static String firstCharToUpperCase(String str) { char firstChar = str.charAt(0); if (firstChar >= 'a' && firstChar <= 'z') { char[] arr = str.toCharArray(); arr[0] -= ('a' - 'A'); return new String(arr); } return str; } /** * 字符串为 null 或者为 "" 时返回 true */ public static boolean isBlank(String str) { return str == null || "".equals(str.trim()); } /** * 字符数组有一个元素为 null 或者为 "" 返回true */ public static boolean isAnyBlank(String[] strArray) { if (strArray == null || strArray.length == 0) { return true; } for (String str : strArray) { if (isBlank(str)) { return true; } } return false; } public static boolean notBlank(String... strings) { if (strings == null) { return false; } for (String str : strings) { if (str == null || "".equals(str.trim())) { return false; } } return true; } public static boolean notNull(Object... paras) { if (paras == null) { return false; } for (Object obj : paras){ if (obj == null) { return false; } } return true; } //首字母转小写 public static String toLowerCaseFirstOne(String s){ if(Character.isLowerCase(s.charAt(0))) { return s; } else { return (new StringBuilder()).append(Character.toLowerCase(s.charAt(0))).append(s.substring(1)).toString(); } } //首字母转大写 public static String toUpperCaseFirstOne(String s){ if(Character.isUpperCase(s.charAt(0))) { return s; } else { return (new StringBuilder()).append(Character.toUpperCase(s.charAt(0))).append(s.substring(1)).toString(); } } /** * 将字符串类型的数字转换为int类型 转换发生异常返回默认值 */ public static int parseToInt(String src, int defaultNum) { try { return Integer.parseInt(src); } catch (NumberFormatException e) { return defaultNum; } } /** * 将包含下划线"_"的原生sql列名转换成javaBean对应的小驼峰形式的属性名 */ public static String _2Camel(String columns){ StringBuffer fieldName = new StringBuffer(); String[] columnArr; if(columns.contains("_")){ columnArr = columns.split("_"); }else{ columnArr = new String[]{columns}; } for (String s : columnArr) { fieldName.append( StrKit.toUpperCaseFirstOne(s)); } return StrKit.toLowerCaseFirstOne(fieldName.toString()); } public static byte[] getBytesWithDefaultEncoding(String str) { try { return str.getBytes(DEFAULT_ENCODING); } catch (UnsupportedEncodingException e) { //应该永远不会发生 DEFAULT_ENCODING 肯定是对的 throw new RuntimeException(e); } } public static String byteToStringWithDefaultEncoding(byte[] bytes){ try { return new String(bytes, DEFAULT_ENCODING); } catch (UnsupportedEncodingException e) { //应该永远不会发生 DEFAULT_ENCODING 肯定是对的 throw new RuntimeException(e); } } /** * 生成随机数 */ public static String getRandomStrNum(){ return (r.nextInt(900000)+100000) + (r.nextInt(900000)+100000)+""; } /** * 将数组的每个元素trim */ public static void trim(String[] patterns) { for (int i = 0; i < patterns.length; i++) { patterns[i] = patterns[i].trim(); } } /** * 检查某个值是否在数组中 */ public static boolean targetInArray(T[] array, T target) { if(null == array || array.length == 0){ return false; } for (T s : array) { if(s.equals(target)){ return true; } } return false; } public static void main(String[] args) { System.out.println(StrKit.getRandomStrNum()); } }