datainputexample.java

JAVA SE6 全方位学习 朱仲杰 编著 机械工业出版社出版

package java2.G;

import java.io.*;
import java.util.*;
import static java.lang.System.*;

public class DataInputExample
{
	public static void main(String[] args) throws IOException
	{
		//Variables declare
		int totalAge = 0;
		double totalHeight = 0.0;
		double totalWeight = 0.0;
		int totalPerson = 0;
		Map<String, Integer> cities = new HashMap<String, Integer>();

		//Read data from file
		BufferedReader br = new BufferedReader(
												new FileReader("d:\\java2\\G\\info.txt"));		
		
		//Parsing data
		String data;
		while((data = br.readLine()) != null)
		{
			totalPerson++;
			StringTokenizer st = new StringTokenizer(data, ",");
			if(st.hasMoreTokens() )
			{
				int no = Integer.parseInt(st.nextToken());
				String name = st.nextToken();
				totalAge += Integer.parseInt(st.nextToken());
				totalHeight += Double.parseDouble(st.nextToken());
				totalWeight += Double.parseDouble(st.nextToken());
				String tel = st.nextToken();
				
				String city = st.nextToken();
				if (cities.containsKey(city))
				{
					int count = cities.get(city)+1;
					cities.put(city, count);
				}
				else
					cities.put(city, 1);
			}
		}
		
		//Output result
		out.printf("Average age is %d.%n", totalAge/totalPerson);
		out.printf("Average height is %.2f.%n", totalHeight/totalPerson);
		out.printf("Average weight is %.2f.%n", totalWeight/totalPerson);
		
		Set<String> keys = cities.keySet();
		for(String city : keys)
			out.printf("%d persons in %S.%n", cities.get(city), city);
	}
}