Java-Java集合排序

• 一、ListMap 排序

一、ListMap 排序

Java中list里面存放map，根据map中的某一个或多个字段进行排序

import java.util.ArrayList;
 
import java.util.Collections;
import java.util.Comparator;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
 
/**
 * 
 * <p>
 * Description:
 * </p>
 * 
 * @author xuyangwei
 * 
 * @date 2020年7月15日
 * 
 */
public class SortListMap {
	/**
	 * @param args
	 */
	public static void main(String[] args) {
		List<Map<String, Object>> list = new ArrayList<Map<String, Object>>();
		Map<String, Object> map1 = new HashMap<String, Object>();
		map1.put("id", "1");
		map1.put("name", "jack");
		Map<String, Object> map2 = new HashMap<String, Object>();
		map2.put("id", "2");
		map2.put("name", "tom");
		Map<String, Object> map3 = new HashMap<String, Object>();
		map3.put("id", "3");
		map3.put("name", "marry");
		list.add(map1);
		list.add(map3);
		list.add(map2);
		// 排序前
		for (Map<String, Object> map : list) {
			System.out.println(map.get("id"));
		}
		Collections.sort(list, new Comparator<Map<String, Object>>() {
			public int compare(Map<String, Object> o1, Map<String, Object> o2) {
				String id1 = (String) o1.get("id");
				String id2 = (String) o2.get("id"); 
				return id1.compareTo(id2);
			}
 
		});
		// 排序后
		System.out.println("-------------------");
		for (Map<String, Object> map : list) {
			System.out.println(map.get("id"));
		}
 
	}
 }