java 在海量List中根據指定條數進行分組取出

1、工具類

/**
	 * 按照條數對List進行分組
	 * 
	 * @param list   目標集合
	 * @param toIndex  多少條爲一組
	 * @return
	 */
	public static Map groupList(List list,int toIndex){
	    int listSize=list.size();
	    Map map = new HashMap();     //用map存起來新的分組後數據
	    int keyToken = 0;
	    for(int i = 0;i<list.size();i+=toIndex){
	        if(i+toIndex>listSize){        //剩餘幾條newList中就裝幾條
	            toIndex=listSize-i;
	        }
	    List newList = list.subList(i,i+toIndex);
	    map.put("result"+keyToken, newList);
	    keyToken++;
	    }
	    
	    return map;
    }

2、測試方法

public static void main(String[] args) {
		List<MyLjyyxJdjhbShdw> a = new ArrayList<MyLjyyxJdjhbShdw>();
		MyLjyyxJdjhbShdw b1 = new MyLjyyxJdjhbShdw();
		b1.setJdjhbBh("1");
		a.add(b1);
		MyLjyyxJdjhbShdw b2 = new MyLjyyxJdjhbShdw();
		b2.setJdjhbBh("2");
		a.add(b2);
		MyLjyyxJdjhbShdw b3 = new MyLjyyxJdjhbShdw();
		b3.setJdjhbBh("3");
		a.add(b3);
		MyLjyyxJdjhbShdw b4 = new MyLjyyxJdjhbShdw();
		b4.setJdjhbBh("4");
		a.add(b4);
		MyLjyyxJdjhbShdw b5 = new MyLjyyxJdjhbShdw();
		b5.setJdjhbBh("5");
		a.add(b5);
		MyLjyyxJdjhbShdw b6 = new MyLjyyxJdjhbShdw();
		b6.setJdjhbBh("6");
		a.add(b6);
		MyLjyyxJdjhbShdw b7 = new MyLjyyxJdjhbShdw();
		b7.setJdjhbBh("7");
		a.add(b7);
		MyLjyyxJdjhbShdw b8 = new MyLjyyxJdjhbShdw();
		b8.setJdjhbBh("8");
		a.add(b8);
		MyLjyyxJdjhbShdw b9 = new MyLjyyxJdjhbShdw();
		b9.setJdjhbBh("9");
		a.add(b9);
		MyLjyyxJdjhbShdw b10 = new MyLjyyxJdjhbShdw();
		b10.setJdjhbBh("10");
		a.add(b10);
		Map<String,Object> map = groupList(a,3);
		for (Map.Entry<String,Object> entry : map.entrySet()) {
			List<MyLjyyxJdjhbShdw> c = (List<MyLjyyxJdjhbShdw>) entry.getValue();
			for (MyLjyyxJdjhbShdw myLjyyxJdjhbShdw : c) {
				System.out.println(myLjyyxJdjhbShdw.getJdjhbBh());
			}
		}
	}