1、编写一个程序，统计给定文件中每个字母出现的频率。

2、编写一个程序，统计给定文件中包含的单词数目，并按单词表的顺序显示统计结果。


package com.space;

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;

public class Calculate {
public static void main(String[] args) {
FileInputStream fis = null;
int[] cnt = new int[27]; //a-z, upper&lower case ignore, cnt[26] other chars
int i=0;
try {
fis = new FileInputStream(“src/test.txt”);
while((i=fis.read())!=-1){
if(‘A’<=i && i<=’Z’)
i = i -‘A’ + ‘a’;
if((int)’a’<=i && i<=(int)’z’){
cnt[(i-‘a’)]++;
}
else
cnt[26]++; //count other characters
}
for(i=0;i<26;i++){
System.out.println((char)(‘a’+i)+”:”+cnt[i]);
}
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}

}

}

[sourcecode class=”java”]
package com.space;

import java.io.BufferedReader;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.util.Arrays;
import java.util.Comparator;
import java.util.HashMap;
import java.util.Hashtable;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;

public class CalculateWords {
public static void main(String[] args) {
FileReader fr = null;
BufferedReader br = null;
String line = null;
String[] words = null;

HashMap hm = new HashMap();
Hashtable ht = new Hashtable();

try {
fr = new FileReader(“src/test.txt”);
br = new BufferedReader(fr);
while((line = br.readLine())!=null){
words = line.split(“ +”);
for(String word : words){
Integer value = (Integer) ht.get(word);
if(value == null){
value = 1;
ht.put(word, value);
}
else{
value++;
ht.put(word, value);
}
}
}

Set set = ht.entrySet();

Map.Entry[] entries = (Map.Entry[]) set.toArray(new Map.Entry[set.size()]);

Arrays.sort(entries, new Comparator() {
public int compare(Object arg0, Object arg1) {
String key1 = (String) ((Map.Entry) arg0).getKey();
String key2 = (String) ((Map.Entry) arg1).getKey();
return key1.compareTo(key2);
}
});

for(Map.Entry entry : entries){
System.out.println(entry.getKey()+”: “+entry.getValue());
}

System.out.println(“*************”);

Iterator it = ht.entrySet().iterator();
while(it.hasNext()){
Map.Entry entry = (Map.Entry)it.next();
System.out.println(entry.getKey()+”: “+entry.getValue());
}

Iterator iter = ht.keySet().iterator();
while(iter.hasNext()){
String s = (String)iter.next();
System.out.println(s+”: “+ht.get(s));
}

} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}

}

}
[/sourcecode]