Word Count in Java language, 三种不同的方法

package ustc.wordcount;

import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.StringTokenizer;
import java.util.Map.Entry;

public class wc {
	public static void main(String arg[]) {
		int wordCount = 0; // 用于统计单词的总个数
		Map map = new HashMap();// 用于统计各个单词的个数，排序
		String sentence = "hello,my name is Tom,what is your name?he said:\"my name is John\"";
		StringTokenizer token = new StringTokenizer(sentence);// 这个类会将字符串分解成一个个的标记
		while (token.hasMoreTokens()) { // 循环遍历
			wordCount++;
			String word = token.nextToken(", ?.!:\"\"''\n"); // 括号里的字符的含义是说按照,空格
																// ? . : "" ''
																// \n去分割，如果这里你没明确要求，即括号里为空，则默认按照空格，制表符，新行符和回车符去分割
			if (map.containsKey(word)) { // HashMap不允许重复的key，所以利用这个特性，去统计单词的个数
				int count = map.get(word);
				map.put(word, count + 1); // 如果HashMap已有这个单词，则设置它的数量加1
			} else
				map.put(word, 1); // 如果没有这个单词，则新填入，数量为1
		}
		System.out.println("总共单词数：" + wordCount);
		sort(map); // 调用排序的方法，排序并输出！
	}

	public static void sort(Map map) {
		List> infoIds = new ArrayList>(
				map.entrySet());
		Collections.sort(infoIds, new Comparator>() {
			public int compare(Map.Entry o1,
					Map.Entry o2) {
				return (o2.getValue() - o1.getValue());
			}
		}); // 排序
		for (int i = 0; i < infoIds.size(); i++) { // 输出
			Entry id = infoIds.get(i);
			System.out.println(id.getKey() + ":" + id.getValue());
		}
	}
}

package ustc.wordcount;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.PriorityQueue;
import java.util.Queue;
import java.util.Set;

import javax.swing.JOptionPane;

public class wc2 {
	public static void main(String[] args) {
		// 获取输入文字列
		String input = JOptionPane.showInputDialog("Please input character!");

		while (null == input || "".equals(input.trim())) {
			JOptionPane.showMessageDialog(null, "Please input character!");
			input = JOptionPane.showInputDialog("Please input character!");
		}
		// 取出单词
		String[] ary = input.split("\\s+");

		List list = new ArrayList();
		for (String str : ary) {
			// 取出的单词数组中提出标点符号
			if (!str.matches("\\W+")) {
				list.add(str);
			}
		}
		// 创建集合对象,将链表存入集合对象,自动删除重复单词,此时集合的size就是剔除重复后的单词个数
		Set set = new HashSet(list);
		// 创建映射对象,以单词出现次数为key,单词内容为value存储
		Map map = new HashMap();
		for (String str : set) {
			int count = 0;
			while (true) {
				int index = list.indexOf(str);
				if (index >= 0) {
					count++;
					list.remove(index);
				} else {
					break;
				}
			}
			// key在map中已经存在时用空格将单词分隔
			if (null == map.get(new Integer(count))) {
				map.put(new Integer(count), str);
			} else {
				String value = map.get(new Integer(count));
				map.put(new Integer(count), str + " " + value);
			}
		}
		// 按照出现次数升序
		sort(map, true);
		// 按照出现次数降序
		sort(map, false);
	}

	/**
	 * 排序用方法.
	 * 
	 * @param map
	 *            待排序容器对象
	 * @param sortType
	 *            排序种别,true表示升序,false表示降序
	 */
	public static void sort(Map map, boolean sortType) {
		List list = new ArrayList();
		// 创建优先队列用于排序
		Queue queue = new PriorityQueue(map.keySet());

		String[] ary;
		while (queue.size() != 0) {
			Integer integer = queue.poll();
			if (!sortType) {
				ary = map.get(integer).split(" ");
				for (String str : ary) {
					list.add(0, str + "有" + integer + " 个");
				}
			} else {
				ary = map.get(integer).split(" ");
				for (String str : ary) {
					list.add(str + "有" + integer + " 个");
				}
			}
		}
		System.out.println(list);

	}
}
 
  
 
  
 
  
 
  
package ustc.wordcount;

import java.io.BufferedReader;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.util.*;
 
public class wc3 {
    public static void main(String[] args) {
        try {
            BufferedReader br = new BufferedReader(new FileReader("D:\\test.txt"));
            String s;
            StringBuffer sb = new StringBuffer();
            while ((s = br.readLine()) != null) {
                sb.append(s);
            }
            br.close();
            Map map = new HashMap();
            StringTokenizer st = new StringTokenizer(sb.toString(),",.! \n");
            while (st.hasMoreTokens()) {
                String letter = st.nextToken();
                int count;
                if (map.get(letter) == null) {
                    count = 1;
                } else {
                    count = map.get(letter).intValue() + 1;
                }
                map.put(letter,count);
            }
            Set set = new TreeSet();
            for (String key : map.keySet()) {
                set.add(new WordEntity(key,map.get(key)));
            }
            // 自己拼接字符串，输出我们想要的字符串格式
            System.out.println("输出形式一：");
            for (Iterator it = set.iterator(); it.hasNext(); ) {
                WordEntity w = it.next();
                System.out.println("单词:" + w.getKey() + " 出现的次数为： " + w.getCount());
            }
            // 直接打印 WordEntity 对象，实现我们想要的输出效果，只需在WordEntity类中重写toString()方法
            System.out.println("输出形式二：");
            for (Iterator it = set.iterator(); it.hasNext(); ) {
                WordEntity w = it.next();
                System.out.println(w);
            }
            // 我们可以控制只输出前三名来
            System.out.println("输出形式三：");
            int count = 1;
            for (Iterator it = set.iterator(); it.hasNext(); ) {
                WordEntity w = it.next();
                System.out.println("第" + count + "名为单词:" + w.getKey() + " 出现的次数为： "
                        + w.getCount());
                if (count == 3)// 当输出3个后跳出循环
                    break;
                count++;
            }
        } catch (FileNotFoundException e) {
            System.out.println("文件未找到~！");
        } catch (IOException e) {
            System.out.println("文件读异常~！");
        }
    }
}
 
 
 
//WordEntity.java文件
 
class WordEntity implements Comparable {
    private String key;
    private Integer count;
    public WordEntity (String key, Integer count) {
        this.key = key;
        this.count = count;
    }
    public int compareTo(WordEntity o) {
        int cmp = count.intValue() - o.count.intValue();
        return (cmp == 0 ? key.compareTo(o.key) : -cmp);
        //只需在这儿加一个负号就可以决定是升序还是降序排列  -cmp降序排列，cmp升序排列
        //因为TreeSet会调用WorkForMap的compareTo方法来决定自己的排序
    }
 
   @Override
    public String toString() {
        return key + " 出现的次数为：" + count;
    }
 
   public String getKey() {
        return key;
    }
 
   public Integer getCount() {
        return count;
    }
}