利用Set List Map集合的特点处理重复字符串

empty public class ForString { /* * 清除重复字符，返回字符串 */ public String getString(String str){ Set s = new HashSet (); char[] ch = str.toCharArray(); for (char c : ch) { s.add(c); } StringBuffer sb = new StringBuffer(); for (char c : s) { sb.append(c); } return sb.toString(); } /* * 返回重复的字符串 */ public String getCFString(String str){ Set s = new HashSet ();//清除重复的字符串 Set s2 = new HashSet ();//存放重复的字符串 char[] ch = str.toCharArray(); for (char c : ch) { boolean b = s.add(c); if(!b){ s2.add(c); } } StringBuffer sb = new StringBuffer(); for (char c : s2) { sb.append(c); } return sb.toString(); } /* * 返回不重复的字符串 */ public String getNoCF(String str){ Set s = new HashSet ();//清除重复的字符串 Set s2 = new HashSet ();//存放重复的字符串 Set s3 = new HashSet ();//存放不重复的字符串 char[] ch = str.toCharArray(); for (char c : ch) { boolean b = s.add(c); if(!b){ s2.add(c); } } s3.addAll(s); s3.removeAll(s2); StringBuffer sb = new StringBuffer(); for (char c : s3) { sb.append(c); } return sb.toString(); } /* * 返回Map集合 */ public Map getStringNum(String str){ char[] ch = str.toCharArray(); Map map = new HashMap (); System.out.println(str); for (char c : ch) { if(map.containsKey(c)){ Integer i = map.get(c); i++; map.put(c, i); }else{ map.put(c, 1); } } return map; } }