【Java】员工统计

1.定义个文档“员工.txt”，里面的内容为：
李文，北京
李希，北京
张小小，河南
王文，河北
董信，北京
张坤，北京
万三，江西
戴天，河南
庞大，湖北
彭克，浙江

生成另外一个文档“员工统计.txt”中，其格式为：
北京,4(董信,李文,李希,张坤)
河南,2(戴天,张小小)
河北,1(王文)
江西,1(万三)
湖北,1(庞大)
浙江,1(彭克)

使用类集方法

使用List接口

package chapter13;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.util.ArrayList;

public class Job {

	public static void main(String[] args) throws IOException  {
		// TODO Auto-generated method stub
		String file1 = "d:/员工.txt";
		File f1 = new File(file1);
		FileReader in = new FileReader(f1);
		BufferedReader breader = new BufferedReader(in);
		String aLine;
		ArrayList<String> listProvince = new ArrayList<String>();
		ArrayList<Integer> listNumber = new ArrayList<Integer>();
		ArrayList<String> listDetail = new ArrayList<String>();
		
		while ((aLine = breader.readLine()) !=  null)
		{
			String name = aLine.substring(0, aLine.indexOf("，"));        //取出从0到”，“变成子字符串
			String province = aLine.substring(aLine.indexOf("，" ) + 1);//取出”，“以后的所有子字符串
			int pos = 0;
			boolean find = false;
			for (int i = 0; i < listProvince.size(); i++)
			{
				if (province.equals(listProvince.get(i)))
				{
					pos = i;
					find = true;
					break;
				}
			}
			if (find)
			{
				listNumber.set(pos, (int)listNumber.get(pos) + 1);
				listDetail.set(pos, listDetail.get(pos) + "," + name);
			}
			else
			{
				listProvince.add(province);
				listNumber.add(1);
				listDetail.add(name);
			}
		}
		breader.close();
		String file2 = "d:/员工统计.txt";
		File f2 = new File(file2);
		if(f2.exists())
			f2.delete();
		FileWriter writerStream = new FileWriter(file2);
		BufferedWriter bwriter = new BufferedWriter(writerStream);
		
		for(int i = 0; i < listProvince.size(); i++)
		{
			aLine = listProvince.get(i) + "," + listNumber.get(i) + "(" + listDetail.get(i) + ")\r\n";
			bwriter.write(aLine);
		}
		bwriter.flush();
		bwriter.close();
	}

}

使用Map接口

package chapter13;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;

public class Job2 {

	public static void main(String[] args) throws IOException {
		// TODO Auto-generated method stub
		String file = "d:/员工.txt";
		FileReader in = new FileReader(file);
		BufferedReader breader = new BufferedReader(in);
		Map<String, String> map = new HashMap<String, String>();
		String aLine;
		while((aLine = breader.readLine()) != null)
		{
			String name = aLine.substring(0, aLine.indexOf("，"));
			String province = aLine.substring(aLine.indexOf("，") + 1);
			if(map.get(province) != null)
			{
				map.replace(province, map.get(province) + "，" + name);
			}
			else
				map.put(province, name);
			breader.close();
			Set<String> keys = map.keySet();
			Iterator<String> iter = keys.iterator();
			String file2 = "d:/员工统计.txt";
			File f = new File(file2);
			if(f.exists())
				f.delete();
			FileWriter writerStream = new FileWriter(file2);
			BufferedWriter bwriter = new BufferedWriter(writerStream);
			while(iter.hasNext())
			{
				String str = iter.next();
				String[] split = map.get(str).split(",");    //把一个字符串分隔成字符串数组，分隔符为”，“
				bwriter.write(str + "," + split.length + "(" + map.get(str) + ")\r\n");    //获取分隔数组长度
			}
			bwriter.flush();
			bwriter.close();
		}
	}

}