课程九，课堂测试

package harrypoter;

import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.text.DecimalFormat;
public class first{

    public static void main(String[] args) {
        double num=0;
        int[] freArray = new int[52];
        char[] charArray = loadCharArrayFromFileName("C:\\Users\\凋零\\Desktop\\Harry Potter and the Sorcerer's Stone.txt");
        computeFrequency(freArray, charArray);
        for(int i = 0; i < freArray.length; i++) {
            num+=freArray[i];
        }
        System.out.println(num);
        DecimalFormat df = new DecimalFormat("######0.00");
        int a=freArray[0];
        
        for (int i = 0; i < freArray.length; i++) {
            System.out.println(((char) ('a' + i)) + ":" + freArray[i]+" "+df.format((100*freArray[i])/num)+"%");
        }
        for (int i = 26; i < freArray.length; i++) {
            System.out.println(((char) ('A' + i-26)) + ":" + freArray[i]+" "+df.format((100*freArray[i])/num)+"%");

        }
    }
    public static void computeFrequency(int[] freArray, char[] charArray) {
        for (int i = 0; i < charArray.length; i++) {
            if (charArray[i] >= 'A' && charArray[i] <= 'Z') {
                freArray[charArray[i] - 'A'+26]++;
            }
            if (charArray[i] >= 'a' && charArray[i] <= 'z') {
                freArray[charArray[i] - 'a']++;
            }
        }
    }
    public static char[] loadCharArrayFromFileName(String name) {
        char[] charArray = new char[5000000];
        File file = new File(name);
        FileReader fr = null;
        try {
            fr = new FileReader(file);
            fr.read(charArray);
            return charArray;
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                fr.close();
            } catch (IOException e) {

                e.printStackTrace();
            }
        }
        return null;
    }

}

 测试二：

package harrypoter;

import java.io.BufferedReader;
import java.io.FileReader;
import java.util.*;


public class second {
    public static void main(String [] args) throws Exception {

        BufferedReader br = new BufferedReader(new FileReader("C:\\Users\\凋零\\Desktop\\Harry Potter and the Sorcerer's Stone.txt"));

        StringBuffer sb = new StringBuffer();
        String text =null;
        while ((text=br.readLine())!= null){
            sb.append(text);
        }
        br.close();  // 关闭读入流

        String str = sb.toString().toLowerCase(); // 将stringBuffer转为字符并转换为小写
        String[] words = str.split("[^(a-zA-Z)]+");  // 非单词的字符来分割，得到所有单词
        Map<String ,Integer> map = new HashMap<String, Integer>() ;

        for(String word :words){
            if(map.get(word)==null){  
                map.put(word,1);
            }else{
                map.put(word,map.get(word)+1);  // 若存在，次数累加1
            }
        }

        // 排序
        List<Map.Entry<String ,Integer>> list = new ArrayList<Map.Entry<String,Integer>>(map.entrySet());

        Comparator<Map.Entry<String,Integer>> comparator = new Comparator<Map.Entry<String, Integer>>() {
            public int compare(Map.Entry<String, Integer> left, Map.Entry<String, Integer> right) {
                return (left.getValue().compareTo(right.getValue()));
            }
        };
        // 集合默认升序升序
        Collections.sort(list,comparator);

        for(int i=0;i<list.size();i++){// 由高到低输出
            System.out.println(list.get(list.size()-i-1).getKey() +":"+list.get(list.size()-i-1).getValue());
        }

    }
}

 测试三：

package harrypoter;

import java.io.BufferedReader;
import java.io.FileReader;
import java.util.*;


public class second {
    public static void main(String [] args) throws Exception {

        BufferedReader br = new BufferedReader(new FileReader("C:\\Users\\凋零\\Desktop\\Harry Potter and the Sorcerer's Stone.txt"));

        StringBuffer sb = new StringBuffer();
        String text =null;
        while ((text=br.readLine())!= null){
            sb.append(text);// 将读取出的字符追加到stringbuffer中
        }
        br.close();  // 关闭读入流

        String str = sb.toString().toLowerCase(); // 将stringBuffer转为字符并转换为小写
        String[] words = str.split("[^(a-zA-Z)]+");  // 非单词的字符来分割，得到所有单词
        Map<String ,Integer> map = new HashMap<String, Integer>() ;

        for(String word :words){
            if(map.get(word)==null){  // 若不存在说明是第一次，则加入到map,出现次数为1
                map.put(word,1);
            }else{
                map.put(word,map.get(word)+1);  // 若存在，次数累加1
            }
        }

        // 排序
        List<Map.Entry<String ,Integer>> list = new ArrayList<Map.Entry<String,Integer>>(map.entrySet());

        Comparator<Map.Entry<String,Integer>> comparator = new Comparator<Map.Entry<String, Integer>>() {
            public int compare(Map.Entry<String, Integer> left, Map.Entry<String, Integer> right) {
                return (left.getValue().compareTo(right.getValue()));
            }
        };
        // 集合默认升序升序
        Collections.sort(list,comparator);

        for(int i=0;i<list.size();i++){// 由高到低输出
            System.out.println(list.get(list.size()-i-1).getKey() +":"+list.get(list.size()-i-1).getValue());
        }

    }
}