把list中根据相同属性（合为一个），计算不同属性转化为另外一个list

1.原list封装

    package test;




import java.io.Serializable;
import java.util.Date;


/**
 * Created by hongdi.ren.
 */
public class PrinterStatusLog implements Serializable{
    
    private int id;


    private int shopId;
    
    private int deviceNumber;
    
    private int connectStatus;
    private Date statusTime;
   
    private Date addTime;
   
    private Date updateTime;
    public int getPaperStatus() {
		return paperStatus;
	}


	public void setPaperStatus(int paperStatus) {
		this.paperStatus = paperStatus;
	}


	private int paperStatus;
    public int getId() {
        return id;
    }


    public void setId(int id) {
        this.id = id;
    }


    public int getShopId() {
        return shopId;
    }


    public void setShopId(int shopId) {
        this.shopId = shopId;
    }


    public int getDeviceNumber() {
        return deviceNumber;
    }


    public void setDeviceNumber(int deviceNumber) {
        this.deviceNumber = deviceNumber;
    }


    public int getConnectStatus() {
        return connectStatus;
    }


    public void setConnectStatus(int connectStatus) {
        this.connectStatus = connectStatus;
    }


    
    public Date getStatusTime() {
        return statusTime;
    }


    public void setStatusTime(Date statusTime) {
        this.statusTime = statusTime;
    }


    


    public Date getAddTime() {
        return addTime;
    }


    public void setAddTime(Date addTime) {
        this.addTime = addTime;
    }


    
   


    public Date getUpdateTime() {
        return updateTime;
    }


    public void setUpdateTime(Date updateTime) {
        this.updateTime = updateTime;
    }


    @Override
    public String toString() {
        final StringBuilder sb = new StringBuilder("PrinterStatusLog{");


        sb.append("shopId=").append(shopId);
        
        sb.append(", deviceNumber=").append(deviceNumber);
       
 
        sb.append(", connectStatus=").append(connectStatus);
        sb.append(", statusTime=").append(statusTime);
       


        sb.append(", updateTime=").append(updateTime);
        sb.append('}');
        return sb.toString();
    }
}

2.转换后的list（根据shopId&&deviceNumber相同的元素，转化为另外一个list，并且计算出connectstatus中0和1的个数，放在第二个list的offlinderimes和onlinetimes中，并保留addtime,updatetime,statusTime最近的的时间）

	
package test;


import java.util.Date;


/**
 * Created by Administrator on 2016/5/24.
 */
public class PrinterStatusVO {


	 private int shopId;
	    private String shopName;
	    private String cityName;
	    private int deviceNumber;


	    private Date statusTime;


	    private Date firstTime;


	    private Date lastTime;




	    private int connectStatus;
	    /**
	     * 上线次数
	     */


	    private int onlineTimes;
	    /**
	     * 下线次数
	     */
	    private int offlineTimes;


	    public int getShopId() {
	        return shopId;
	    }




	    public void setShopId(int shopId) {
	        this.shopId = shopId;
	    }


	    public String getShopName() {
	        return shopName;
	    }


	    public void setShopName(String shopName) {
	        this.shopName = shopName;
	    }


	    public int getDeviceNumber() {
	        return deviceNumber;
	    }


	    public void setDeviceNumber(int deviceNumber) {
	        this.deviceNumber = deviceNumber;
	    }


	    public Date getStatusTime() {
	        return statusTime;
	    }


	    public void setStatusTime(Date statusTime) {
	        this.statusTime = statusTime;
	    }


	    public Date getLastTime() {
	        return lastTime;
	    }


	    public void setLastTime(Date lastTime) {
	        this.lastTime = lastTime;
	    }


	    public Date getFirstTime() {
	        return firstTime;
	    }


	    public void setFirstTime(Date firstTime) {
	        this.firstTime = firstTime;
	    }


	    public int getOnlineTimes() {
	        return onlineTimes;
	    }


	    public void setOnlineTimes(int onlineTimes) {
	        this.onlineTimes = onlineTimes;
	    }


	    public int getOfflineTimes() {
	        return offlineTimes;
	    }


	    public void setOfflineTimes(int offlineTimes) {
	        this.offlineTimes = offlineTimes;
	    }


	    public String getCityName() {
	        return cityName;
	    }


	    public void setCityName(String cityName) {
	        this.cityName = cityName;
	    }


	    public int getConnectStatus() {
	        return connectStatus;
	    }


	    public void setConnectStatus(int connectStatus) {
	        this.connectStatus = connectStatus;
	    }


	    @Override
	    public String toString() {
	        final StringBuilder sb = new StringBuilder("PrinterStatusLogVO{");


	        sb.append("shopId=").append(shopId);
	       


	        sb.append(", deviceNumber=").append(deviceNumber);
	        sb.append(", statusTime=").append(statusTime);
	        sb.append(", firstTime=").append(firstTime);


	        sb.append(", lastTime=").append(lastTime);


	        sb.append(", onlineTimes=").append(onlineTimes);


	        sb.append(", offlineTimes=").append(offlineTimes);
	        sb.append('}');
	        return sb.toString();
	    }


	}

3.测试：

		
	package test;


import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Date;
import java.util.HashMap;
import java.util.List;


import net.sf.json.JSONArray;


public class ListToList {
	public static final SimpleDateFormat FORMAT = new SimpleDateFormat("yyyy-MM-dd");


	public static void main(String[] args) {
		List list = new ArrayList();


		PrinterStatusLog n5 = new PrinterStatusLog();


		n5.setShopId(1);
		n5.setDeviceNumber(2);
		n5.setConnectStatus(0);
		try {
			n5.setStatusTime(FORMAT.parse("2016-03-27"));
			n5.setUpdateTime(FORMAT.parse("2016-04-01"));
		} catch (ParseException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}


		System.out.println("转化之前n1:" + n5.toString());
		PrinterStatusLog n2 = new PrinterStatusLog();
		n2.setShopId(1);
		n2.setDeviceNumber(3);
		n2.setConnectStatus(1);
		try {
			n2.setStatusTime(FORMAT.parse("2016-03-28"));
			n2.setUpdateTime(FORMAT.parse("2016-03-29"));
		} catch (ParseException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}


		System.out.println("转化之前："+"n2:" + n2.toString());
		PrinterStatusLog n3 = new PrinterStatusLog();
		n3.setShopId(2);
		n3.setDeviceNumber(4);
		n3.setConnectStatus(1);
		try {
			n3.setStatusTime(FORMAT.parse("2016-03-29"));
			n3.setUpdateTime(FORMAT.parse("2016-04-09"));
		} catch (ParseException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		System.out.println("转化之前："+"n3:" + n3.toString());


		PrinterStatusLog n4 = new PrinterStatusLog();
		n4.setShopId(2);
		n4.setDeviceNumber(4);
		n4.setConnectStatus(1);
		try {
			n4.setStatusTime(FORMAT.parse("2016-03-30"));
			n4.setUpdateTime(FORMAT.parse("2016-05-01"));
		} catch (ParseException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		System.out.println("转化之前："+"n4:" + n4.toString());


		PrinterStatusLog n1 = new PrinterStatusLog();
		n1.setShopId(1);
		n1.setDeviceNumber(2);
		n1.setConnectStatus(1);
		try {
			n1.setStatusTime(FORMAT.parse("2016-03-30"));
			n1.setUpdateTime(FORMAT.parse("2016-05-01"));
		} catch (ParseException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		System.out.println("转化之前："+"n5:" + n1.toString());


		list.add(n1);
		list.add(n2);
		list.add(n3);
		list.add(n4);
		list.add(n5);
		List printerStatusLogVOs = mergeList(list);
		for (PrinterStatusVO a : printerStatusLogVOs) {
			System.out.println(a.toString());


		}


	}


	public static List mergeList(List printerStatusLogs) {
		HashMap map = new HashMap();
		List printerStatusLogVOs = newPrinterStatusLogVOList(printerStatusLogs);
		for (PrinterStatusVO bean : printerStatusLogVOs) {
			String keyStr = String.valueOf(bean.getShopId()) + String.valueOf(bean.getDeviceNumber());
			
			if (map.containsKey(keyStr)) {


				bean.setStatusTime(map.get(keyStr).getStatusTime().compareTo(bean.getStatusTime()) == 1
						? map.get(keyStr).getStatusTime() : bean.getStatusTime());
				System.out.println("状态："+bean.getConnectStatus());
				if (bean.getConnectStatus() == PrintStatusCode.ONLINE) {
					if (map.get(keyStr).getFirstTime() == null) {
						bean.setFirstTime(bean.getFirstTime());
					}


					if (bean.getFirstTime() == null) {
						bean.setFirstTime(map.get(keyStr).getFirstTime());
					}


					if (map.get(keyStr).getFirstTime() != null && bean.getFirstTime() != null) {
						bean.setFirstTime(map.get(keyStr).getFirstTime().compareTo(bean.getFirstTime()) == 1
								? bean.getFirstTime() : map.get(keyStr).getFirstTime());
					}
					//问题找到
					bean.setLastTime(map.get(keyStr).getLastTime());
				} else {
					if (map.get(keyStr).getLastTime() == null) {
						bean.setLastTime(bean.getLastTime());
					}


					if (bean.getLastTime() == null) {
						bean.setLastTime(map.get(keyStr).getLastTime());
						System.out.println("map.get(keyStr).getLastTime():"+map.get(keyStr).getLastTime());
					}


					if (map.get(keyStr).getLastTime() != null && bean.getLastTime() != null) {
						bean.setLastTime(map.get(keyStr).getLastTime().compareTo(bean.getLastTime()) == 1
								? map.get(keyStr).getLastTime() : bean.getLastTime());
					}
					//问题找到
					bean.setFirstTime(map.get(keyStr).getFirstTime());
				}


				bean.setOfflineTimes(map.get(keyStr).getOfflineTimes() + bean.getOfflineTimes());
				bean.setOnlineTimes(map.get(keyStr).getOnlineTimes() + bean.getOnlineTimes());
			}
			
			map.put(keyStr, bean);
			System.out.println("map状态："+map.get(keyStr).getConnectStatus()+"  "+"F："+map.get(keyStr).getFirstTime()+"  "+"L:"+map.get(keyStr).getLastTime());
			
		}
		printerStatusLogVOs.clear();
		printerStatusLogVOs.addAll(map.values());


		return printerStatusLogVOs;


	}


	private static List newPrinterStatusLogVOList(List list) {
		List printerStatusLogVOList = new ArrayList();
		for (PrinterStatusLog bean : list) {
			// ...HbtShopBO shopBO =
			// hobbitShopService.loadShop(bean.getShopId());
			PrinterStatusVO printerStatusLogVO = new PrinterStatusVO();
			printerStatusLogVO.setShopId(bean.getShopId());
			// printerStatusLogVO.setShopName(shopBO.getShopName());
			// printerStatusLogVO.setCityName(shopBO.getCityName());
			printerStatusLogVO.setDeviceNumber(bean.getDeviceNumber());
			printerStatusLogVO.setStatusTime(bean.getStatusTime());
			printerStatusLogVO.setConnectStatus(bean.getConnectStatus());
			printerStatusLogVO.setOfflineTimes(bean.getConnectStatus() == PrintStatusCode.OFFLINE
					? PrintStatusCode.ONLINE : PrintStatusCode.OFFLINE);
			printerStatusLogVO.setOnlineTimes(bean.getConnectStatus() == PrintStatusCode.ONLINE ? PrintStatusCode.ONLINE
					: PrintStatusCode.OFFLINE);
			if (bean.getConnectStatus() == PrintStatusCode.ONLINE) {
				printerStatusLogVO.setFirstTime(bean.getUpdateTime());
			} else {
				printerStatusLogVO.setLastTime(bean.getUpdateTime());
			}
			System.out.println("转化之后");
			System.out.println("转化之后："+printerStatusLogVO.toString());
			printerStatusLogVOList.add(printerStatusLogVO);
		}
		return printerStatusLogVOList;
	}
}