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);

     }

}