统计一个文本中单词出现的个数(草稿版）

package testProject;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;
import java.util.Map.Entry;

public class Word {
	static Map<String, Integer> sumWords(String str) {
		if (str == null)
			return null;
		str = str.trim();
		int len = str.length();
		if (len == 0)
			return null;
		Map<String, Integer> map = new HashMap<String, Integer>();
		String[] words = str.split("\\s+");
		for (int i = 0; i < words.length; i++) {
			int k = map.get(words[i]) == null ? 0 : map.get(words[i]);
			map.put(words[i], k + 1);
		}
		return map;
	}

	public static void main(String[] args) throws IOException {
		String filename = "C:\\Users\\cxb\\Desktop\\test.txt";
		FileReader fileReader = new FileReader(new File(filename));
		BufferedReader bufferedReader = new BufferedReader(fileReader);
		StringBuffer stringBuffer = new StringBuffer();
		String string = null;
		while ((string = bufferedReader.readLine()) != null) {
			stringBuffer.append(string);
		}
		String str = stringBuffer.toString();
		Map<String, Integer> map = sumWords(str);
		for (Entry<String, Integer> entry : map.entrySet()) {
			System.out.println(entry.getKey() + ":" + entry.getValue());
		}
	}
}