Java实现对两个List快速去重并排序操作示例

package twolist;import java.util.Collections;import java.util.Comparator;import java.util.HashMap;import java.util.HashSet;import java.util.LinkedList;import java.util.List;import java.util.Map;import java.util.Set;public class ListMapSort {     /**   * @param args   */  public static void main(String[] args) {    // TODO 自动生成方法存根    List<Map<String,Object>> listMap1 = new LinkedList<Map<String,Object>>();    Map<String,Object> map = new HashMap<String, Object>();    map.put("date", 20121010);    listMap1.add(map);    map = new HashMap<String, Object>();    map.put("date", 20011213);    listMap1.add(map);    listMap1.add(map);    map = new HashMap<String, Object>();    map.put("date", 20130502);    listMap1.add(map);    System.out.println("原始"+listMap1);    List<Map<String,Object>> listMap2 = new LinkedList<Map<String,Object>>();    Set<Map> setMap = new HashSet<Map>();    for(Map<String,Object> map1 : listMap1){      if(setMap.add(map1)){        listMap2.add(map1);      }    }    System.out.println("去重"+listMap2);    Collections.sort(listMap2, new Comparator<Map<String,Object>>(){      public int compare(Map<String,Object> o1,Map<String,Object> o2){        return o1.get("date").toString().compareTo(o2.get("date").toString());      }    });    System.out.println("排序:"+listMap2);  }}

package twolist;import java.util.ArrayList;import java.util.HashMap;import java.util.List;import java.util.Map;import java.util.Set;public class RemoveList {    private <K, V> void cleanListByMapKey(List<Map<K,V>> list, K toBeRemoved) {      List<Map<K,V>> tmpList=new ArrayList<>();      for(Map<K,V> m: list){        if(m.containsKey(toBeRemoved))          tmpList.add(m);      }      list.removeAll(tmpList);    }    public void testCleanListByMapKey(){      List<Map<String,String>> list=new ArrayList<>();      for(int i=0;i<10;i++){        Map<String, String> m=new HashMap<>();        m.put("key"+i, "value"+i);        list.add(m);      }      Map<String, String> m=new HashMap<>();      m.put("key100", "value100");      list.add(m);      System.out.println(list.contains(m));      cleanListByMapKey(list, "key100");      System.out.println(list.contains(m));    }    public static void main(String[] args) {        /*RemoveList remove = new RemoveList();        remove.testCleanListByMapKey();*/        // TODO Auto-generated method stub    Map<String, Map> msp = new HashMap<String, Map>();    List<Map<String, Object>> list = new ArrayList<Map<String, Object>>();    List<Map<String, Object>> listMap = new ArrayList<Map<String,Object>>();    Map<String, Object> map1 = new HashMap<String, Object>();    map1.put("id", "1");    map1.put("name", "p");    Map<String, Object> map2 = new HashMap<String, Object>();    map2.put("id", "3");    map2.put("name", "h");    Map<String, Object> map3 = new HashMap<String, Object>();    map3.put("id", "3");    map3.put("name", "f");    list.add(map1);    list.add(map3);    list.add(map2);    System.out.println("初始数据：" + list.toString());    //把list中的数据转换成msp,去掉同一id值多余数据，保留查找到第一个id值对应的数据    for(int i = list.size()-1 ; i>=0; i--){      Map map = list.get(i);      String id = (String)map.get("id");      map.remove("id");      msp.put(id, map);    }     //把msp再转换成list,就会得到根据某一字段去掉重复的数据的List<Map>    Set<String> mspKey = msp.keySet();    for(String key: mspKey){      Map newMap = msp.get(key);      newMap.put("id", key);      listMap.add(newMap);    }    System.out.println("去掉重复数据后的数据：" + listMap.toString());    }}

//第一步：先将原始订单中跟退款中一模一样的移除出来Map<String,Object> wsMap = new HashMap<String, Object>();for (ApplyReturn applyReturn : groupItemList) {    //格式itemId_color_size  qua    wsMap.put(applyReturn.getItemId()+"_"+applyReturn.getColor()+"_"+applyReturn.getSize(), applyReturn.getQua());}List<OrderDetail> newListOrderDetails = new ArrayList<OrderDetail>();List<OrderDetail> listOrderDetail = order.getDetails();//第二步：再来遍历剩下的int mapQua = 0;for (OrderDetail orderDetail : listOrderDetail) {    if(wsMap.get(orderDetail.getTid()+"_"+orderDetail.getKcolor()+"_"+orderDetail.getKsize())!=null){        mapQua = Integer.parseInt(wsMap.get(orderDetail.getTid()+"_"+orderDetail.getKcolor()+"_"+orderDetail.getKsize()).toString());        if(mapQua<orderDetail.getQua()){            OrderDetail newOrderDetail = orderDetail;            newOrderDetail.setQua(orderDetail.getQua()-mapQua);            newListOrderDetails.add(newOrderDetail);        }    }else{        newListOrderDetails.add(orderDetail);    }}