Java List根据对象的某个属性合并list

package com.test;

import java.util.ArrayList;
import java.util.List;

public class FileTest {
	public static void main(String[] args) {
		List<FileBean> beans=new ArrayList<FileBean>();
		FileBean bean1=new FileBean();
		bean1.setDirectory("path1");
		bean1.setSize(20);
		beans.add(bean1);
		FileBean bean2=new FileBean();
		bean2.setDirectory("path1");
		bean2.setSize(30);
		beans.add(bean2);
		FileBean bean3=new FileBean();
		bean3.setDirectory("path1");
		bean3.setSize(40);
		beans.add(bean3);
		FileBean bean4=new FileBean();
		bean4.setDirectory("path2");
		bean4.setSize(50);
		beans.add(bean4);
		FileBean bean5=new FileBean();
		bean5.setDirectory("path2");
		bean5.setSize(60);
		beans.add(bean5);
		FileBean bean6=new FileBean();
		bean6.setDirectory("path3");
		bean6.setSize(70);
		beans.add(bean6);
		FileBean bean7=new FileBean();
		bean7.setDirectory("path3");
		bean7.setSize(80);
		beans.add(bean7);
		FileBean bean8=new FileBean();
		bean8.setDirectory("path3");
		bean8.setSize(90);
		beans.add(bean8);
		List<FileBean> result = transferFilebean(beans);
		System.out.println(result.size());
		for(int i = 0; i< result.size();i++){
			FileBean bean = result.get(i);
			System.out.println(bean.getDirectory() + ";" + bean.getSize());
			
		}
	}
	
	public static List<FileBean> transferFilebean(List<FileBean> beans){
		List<FileBean> result = new ArrayList<FileBean>();
		
		if(beans == null){
			return result;
		}
		for(int i = 0; i< beans.size();i++){
			FileBean bean = beans.get(i);
			if(!result.contains(bean)){
				for(int j = i+1; j< beans.size();j++){
					FileBean bean2 = beans.get(j);
					if(bean.equals(bean2)){
						bean.setSize(bean.getSize()+bean2.getSize());
					}
				}
				result.add(bean);
			}
		}
		return result;
	}

}

class FileBean {
	private String directory;
	private long size;
	private int dirNum;
	public String getDirectory() {
		return directory;
	}
	public void setDirectory(String directory) {
		this.directory = directory;
	}
	public long getSize() {
		return size;
	}
	public void setSize(long size) {
		this.size = size;
	}
	
	public int getDirNum() {
		return dirNum;
	}
	public void setDirNum(int dirNum) {
		this.dirNum = dirNum;
	}
	@Override
	public int hashCode() {
		final int prime = 31;
		int result = 1;
		result = prime * result + ((directory == null) ? 0 : directory.hashCode());
		result = prime * result + (int) (size ^ (size >>> 32));
		return result;
	}
	@Override
	public boolean equals(Object obj) {
		if (this == obj)
			return true;
		if (obj == null)
			return false;
		if (getClass() != obj.getClass())
			return false;
		FileBean other = (FileBean) obj;
		if (directory == null) {
			if (other.directory != null)
				return false;
		} else if (!directory.equals(other.directory))
			return false;
		return true;
	}

}

posted @ 2017-10-09 15:04  技术即艺术  阅读(11795)  评论(0编辑  收藏  举报