Java 文件统计：编写程序，统计英文文本文件中的字符数目和单词数目。程序运行时，输入要统计的文件的名称，程序处理后输出字符数目和单词数目

package text6;

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

import javax.swing.JOptionPane;

class tongji {
public static void main( String[ ] args ) throws Exception {
String str = JOptionPane.showInputDialog("请输入字符串(例如:text6.txt)：");
File file = new File(str);
FileReader reader = new FileReader(file);
int length = (int)file.length();
char[] chars = new char[length];
reader.read(chars);
reader.close();
String s = String.valueOf(chars);

int count = 0;
int n = chars.length;
for(int i = 0; i < n ; i++)
{
if(chars[i] >= 'a' && chars[i] <= 'z')
{
count ++;
}
}

String[ ] words = s.replaceAll( "[^a-zA-Z]+", " " ).trim( ).split( " " );

if ( words.length > 0 ) {
TreeSet<Integer> lengths = new TreeSet<Integer>( );

for ( String word: words )
lengths.add( word.length( ) );
JOptionPane.showMessageDialog(null, "字符数:"+String.valueOf(count) +"\n"+"单词数:"+String.valueOf(words.length));
}
else
JOptionPane.showMessageDialog(null, "字符数:0"+"\n"+"单词数:0");
}
}