[java] view plaincopyprint?
- package demo20130414;
- import java.util.Collection;
- import java.util.Collections;
- import java.util.Comparator;
- import java.util.HashMap;
- import java.util.Iterator;
- import java.util.Map;
- import java.util.Map.Entry;
- import java.util.Set;
- import java.util.ArrayList;
- import java.util.List;
- public class CharCounterDemo {
- /**
- */
- public static void main(String[] args) {
- String str = "aabbccdderffisfalgjgosdrugnsdsduhgdsfugsdogosdjgosdig";
- Map<Character, Integer> map = countAll(str);
- System.out.println(map);
- // 迭代Map: 迭代所有的key,迭代所有的value迭代Entry<key,value>
- // 迭代所有的value,实现统计所有的字符总数
- Collection<Integer> values = map.values();
- Iterator<Integer> ite = values.iterator();
- int total = 0;
- while (ite.hasNext()) {
- Integer n = ite.next();
- total += n;
- System.out.print(n + " ");
- }
- System.out.println("字符总数:" + total);
- // 迭代所有的key,利用迭代所有字符实现输出统计表格
- Set<Character> keys = map.keySet();
- System.out.println("字符串中所有字符的个数:" + keys.size());
- ArrayList<Character> list = new ArrayList<Character>(keys);
- Collections.sort(list);// 自然排序
- for (Iterator<Character> i = list.iterator(); i.hasNext();) {
- Character ch = i.next();
- int n = map.get(ch);
- System.out.print(ch + ":");
- System.out.println(n + " " + ((float) n / total) * 100 + "%");
- // System.out.print(ch);
- }
- System.out.println("照字符出现的数量排序输出:");
- //迭代Entry<key:Value> 实现按照字符出现的数量排序输出
- Set<Entry<Character, Integer>> entries = map.entrySet();
- List<Entry<Character,Integer>> entList=new ArrayList<Entry<Character,Integer>>(entries);
- Collections.sort(entList, new ByValue());
- for (Iterator<Entry<Character, Integer>> i = entList.iterator(); i.hasNext();) {
- Entry<Character,Integer> entry=i.next();
- Character ch=entry.getKey();
- Integer n=entry.getValue();
- System.out.print(ch + ":");
- System.out.println(n + " " + ((float) n / total) * 100 + "%");
- }
- }
- private static Map<Character, Integer> countAll(String str) {
- int length = str.length();
- Map<Character, Integer> map = new HashMap<Character, Integer>();
- for (int i = 0; i < length; i++) {
- char ch = str.charAt(i);
- if (map.containsKey(ch)) {// 如果包含ch
- int n = map.get(ch);
- map.put(ch, n + 1);
- } else {// 如果不包含ch
- map.put(ch, 1);
- }
- }
- return map;
- }
- }
- class ByValue implements Comparator<Entry<Character,Integer>>{
- public int compare(Entry<Character, Integer> o1,
- Entry<Character, Integer> o2) {
- // TODO Auto-generated method stub
- return -(o1.getValue()-o2.getValue());//从大到小排列
- //return (o1.getValue()-o2.getValue());//从小到大排列
- }
- }