输出某个英文文本文件中 26 字母出现的频率，由高到低排列，并显示字母出现的百分比，精确到小数点后面两位：
package test;
import java.io.BufferedReader;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.text.DecimalFormat;
import java.text.NumberFormat;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Map;
public class W1 {
public static void main(String[] args) throws IOException {
try {
//IO操作读取文件内容
FileReader fr = new FileReader("d:\\文件\\单词.txt");
BufferedReader br = new BufferedReader(fr);
NumberFormat nf = NumberFormat.getInstance();
// 设置精确到小数点后2位
nf.setMaximumFractionDigits(2);
HashMap<String, Integer> map = new HashMap<String, Integer>();
String string =null;
Integer count = 0;//每个字母的次数
Integer total = 0;//总共多少个字母
while ((string=br.readLine())!=null) {
char[] ch = string.toCharArray();
for (int i = 0; i < ch.length; i++) {
if (ch[i] > 'A' && ch[i]< 'z') {
total++;
ch[i] = Character.toLowerCase(ch[i]);
count = map.get(ch[i]+"");
if (count == null) {
count = 1;
}else {
count++;
}
map.put(ch[i]+"", count);
}
}
}
ArrayList<String> list = new ArrayList<String>();
list.addAll(map.keySet()); //将单词添加到list中
//排序按照出现次数降序排列
for(int i = 0;i < list.size();i++)
{
for(int j = 0;j < (list.size() - i-1);j++) //list.size() - i-1因为要用到i+1要考虑是否超出范围的问题
{
if(map.get(list.get(j)) < map.get(list.get(j+1)))
{
String t = list.get(j);
list.set(j, list.get(j+1));
list.set( j+1, t);
}
}
}
for(int i = 0 ; i < list.size();i++)
{
System.out.println(list.get(i) + ":" + map.get(list.get(i)) +" "+ nf.format((float)(map.get(list.get(i)))*100/total) + "%");
}
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
截图
1.输出单个文件中的前 N 个最常出现的英语单词。
2.输出文件中所有不重复的单词，按照出现次数由多到少排列，出现次数同样多的，以字典序排列。
3.指定文件目录，对目录下每一个文件执行统计的操作。
4.指定文件目录，是会递归遍历目录下的所有子目录的文件进行统计单词的功能。
package test;
import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Scanner;
public class W2 {
public static String StatList(String str) {
StringBuffer sb = new StringBuffer();
HashMap<String ,Integer> has = new HashMap<String ,Integer> (); // 打开一个哈希表
String[] slist = str.split("[^a-zA-Z\']+");
for (int i = 0; i < slist.length; i++)
{
if (!has.containsKey(slist[i]))
{
has.put(slist[i], 1);
}
else
{
has.put(slist[i],has.get(slist[i])+1 );
}
}
Iterator<String> iterator = has.keySet().iterator();
String a[]=new String[100];
int s[]=new int[100];
int n=15;
int judge;
Scanner in=new Scanner(System.in);
System.out.println("输入前n个最常出现的单词:");
n=in.nextInt();
for(int i=0;i<n;i++)
{
iterator = has.keySet().iterator();
while(iterator.hasNext())
{
String word = (String) iterator.next();
if(s[i]<has.get(word))
{
s[i]=has.get(word);
a[i]=word;
}
}
judge=woor(a[i]);
if(judge==1)
{
n++;
has.remove(a[i]);
}
else
{
sb.append("单词：").append(a[i]).append(" 次数").append(has.get(a[i])).append("\r\n");
has.remove(a[i]);
}
}
return sb.toString();
}
public static void main(String[] args)
{
File file = new File("d:\\文件");
// // TODO Auto-generated method stub
// ArrayList<String> fil=getFiles("d:\\文件");//目录下的文件
ArrayList<String> fil=getDirectory(file);//目录下的文件和子目录里的文件
for(int i=0;i<fil.size();i++)
{
String filePath = fil.get(i);
//String filePath = "d:\\文件\\单词.txt";
String sz=W3.readTxtFile(filePath);
String ltxt=null;
System.out.println(ltxt=StatList(sz));
try {
W3.daochu(ltxt);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
public static int woor(String a)
{
int n=0;
String[] biao= {"a","the","an","and"};
for(int i=0;i<biao.length;i++)
{
if(biao[i].equals(a))
{
n=1;
}
}
return n;
}
public static ArrayList<String> getFiles(String path) {
ArrayList<String> files = new ArrayList<String>();
File file = new File(path);
File[] tempList = file.listFiles();
for (int i = 0; i < tempList.length; i++) {
if (tempList[i].isFile()) {
files.add(tempList[i].toString());
}
if (tempList[i].isDirectory()) {
}
}
return files;
}
private static ArrayList<String> getDirectory(File file) {
ArrayList<String> files = new ArrayList<String>();
ArrayList<String> files1 = new ArrayList<String>();
//获取该目录下的文件列表
File flist[] = file.listFiles();
for (File f : flist) {
if (f.isDirectory()) {
// 如果f是一个目录
files1=getFiles(f.getAbsolutePath());
files.addAll(files1);
getDirectory(f);
} else {
//如果f是一个文件
files.add(f.getAbsolutePath());
}
}
return files;
}
}
package test;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
//import java.io.Reader;
//从文本文档中读入
public class W3 {
public static String readTxtFile(String filePath){
try {
String encoding="GBK";
File file=new File(filePath);
if(file.isFile() && file.exists()){ //判断文件是否存在
InputStreamReader read = new InputStreamReader(
new FileInputStream(file),encoding);//考虑到编码格式
BufferedReader bufferedReader = new BufferedReader(read);
String lineTxt = null;
String lineText="";
while((lineTxt = bufferedReader.readLine()) != null)
{
lineText+=(lineTxt);
}
read.close();
return lineText;
}
else
{
System.out.println("找不到指定的文件");
}
} catch (Exception e) {
System.out.println("读取文件内容出错");
e.printStackTrace();
}
return null;
}
public static void daochu(String a) throws IOException
{
File file=new File("d:\\文件\\c.txt");
FileOutputStream fos=new FileOutputStream(file);
OutputStreamWriter osw = new OutputStreamWriter(fos,"UTF-8");
osw.append(a);
osw.close();
fos.close();
}
}
package test;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
//import java.io.Reader;
//从文本文档中读入
public class W3 {
public static String readTxtFile(String filePath){
try {
String encoding="GBK";
File file=new File(filePath);
if(file.isFile() && file.exists()){ //判断文件是否存在
InputStreamReader read = new InputStreamReader(
new FileInputStream(file),encoding);//考虑到编码格式
BufferedReader bufferedReader = new BufferedReader(read);
String lineTxt = null;
String lineText="";
while((lineTxt = bufferedReader.readLine()) != null)
{
lineText+=(lineTxt);
}
read.close();
return lineText;
}
else
{
System.out.println("找不到指定的文件");
}
} catch (Exception e) {
System.out.println("读取文件内容出错");
e.printStackTrace();
}
return null;
}
public static void daochu(String a) throws IOException
{
File file=new File("d:\\文件\\c.txt");
FileOutputStream fos=new FileOutputStream(file);
OutputStreamWriter osw = new OutputStreamWriter(fos,"UTF-8");
osw.append(a);
osw.close();
fos.close();
}
}
截图：
