封装一个方法,用一个Map来实现,这里是根据bean类的seq字段进行拆分的,分成好几个list


    private LinkedHashMap<String,List<HandleInfo>> groupListBySeq(List<HandleInfo> list) {
		LinkedHashMap<String,List<HandleInfo>> map = new LinkedHashMap<String,List<HandleInfo>>();
        for (HandleInfo bean : list) {
        	if(map.containsKey(bean.getSeq())){
        		List<HandleInfo> subList = map.get(bean.getSeq());
        		subList.add(bean);
        	}else{
        		List<HandleInfo> subList = new ArrayList<HandleInfo>();
        		subList.add(bean);
        		map.put(bean.getSeq(), subList);
        	}
        }
        return map;
    }


然后可以对获取到的Map进行遍历:

LinkedHashMap<String,List<HandleInfo>> map = groupListBySeq(needUpdateHandleInfoList);
//遍历集合
for(Map.Entry<String, List<HandleInfo>> entry : map.entrySet()){
			List<HandleInfo> list=(List<HandleInfo>)entry.getValue();
			HandleInfo bean0 = new HandleInfo();
			if(null != list || !list.isEmpty()){
				bean0 = list.get(0);
			}
			for(HandleInfo handleInfoModel : list){
				...
			}		
}



上面是按数据库字段进行分组的方法,然后介绍一下平均分成多少数据量的集合

java代码只要获取参数进行集合拆分就可以:

举个例子,下面是一种方法,将list按照没1000个为一个集合分组

List<String> values = new ArrayList<String>();
String[] configSeqArray = StringUtils.split(configSeq,',');
for (String str : configSeqArray) {
		values.add(str);
}
List<Collection<String>> configSeqs = CollectionUtil.splitCollection(values, 1000);

复制公司同事写的集合拆分的方法

import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
public class CollectionUtils {
	public static List<Collection<String>> splitCollection(Collection<String>values , int size) {
		List<Collection<String>> result = new ArrayList<Collection<String>>();
		if(values.size() <= size ){
			result.add(values);
		}else{
				int count =0;
				Collection<String> subCollection= null;
				for(String s:c){
					if(subCollection == null){
						subColletion = new ArrayList<String>();
						result.add(subColletion);
					}
					subCollection.add(s);
					count++;
					if(count == size){
						count =0;
						subCollectiion = null;
					}
				}
		}
	}
}

这种方法可以应用与解决Oracle select in超过1000个的报错,具体参考:https://smilenicky.blog.csdn.net/article/details/87922878