1.List<Map<String,String>>的遍历：
Map<String,String> map = new HashMap<String, String>();
map.put("1", "fds");
map.put("2", "valu");
List<Map<String, String>> list = new ArrayList<Map<String, String>>();
list.add(map);
for (Map<String, String> m : list){
for (String k : m.keySet()){
System.out.println(k + " : " + m.get(k));
}
}
2.两个List<Map<String,String>>相互比较，有相同数据时某些字段相加减
inOrderList与outOrderList放自己的所比较的数据,name,number,id为map的key值
for (int i = 0; i < inOrderList.size(); i++) {//循环获取入库数据
String number1 = String.valueOf(inOrderList.get(i).get("number"));
String depotName1 = inOrderList.get(i).get("name");
String proId1 = inOrderList.get(i).get("id");
for (int j = 0; j < outOrderList.size(); j++) {//循环获取出库数据
String number2 = String.valueOf(outOrderList.get(j).get("number"));
String depotName2 = outOrderList.get(j).get("name");
String proId2 = outOrderList.get(j).get("id");
if (depotName1.equals(depotName2) && proId1.equals(proId2)) {
Integer sum =Integer.parseInt(number1) - Integer.parseInt(number2);//判断是否为同一条数据，同条数据数量相减
inOrderList.get(i).put("number", sum + "");
}
}
}
3.单个List<Map<String,String>>相互比较，相同数据相加(转)
List<Map<String, String>> l = new ArrayList<Map<String,String>>();
Map<String, String> m1 = new HashMap<String, String>(); m1.put("count", "1");
m1.put("name", "帮宝适纸尿裤L164 超薄干爽夏季透气专用婴儿尿不湿");
m1.put("province", "江苏省");
m1.put("date", "2014-09-23 10:13:39");
m1.put("channel", "东环大润发");
m1.put("city", "苏州市");
l.add(m1); Map<String, String> m2 = new HashMap<String, String>();
m2.put("count", "1");
m2.put("name", "帮宝适纸尿裤L164 超薄干爽夏季透气专用婴儿尿不湿");
m2.put("province", "江苏省");
m2.put("date", "2014-09-23 10:13:39");
m2.put("channel", "东环大润发");
m2.put("city", "泰州市");
l.add(m2); Map<String, String> m3 = new HashMap<String, String>();
m3.put("count", "1");
m3.put("name", "帮宝适纸尿裤L164 超薄干爽夏季透气专用婴儿尿不湿");
m3.put("province", "江苏省");
m3.put("date", "2014-09-23 10:13:39");
m3.put("channel", "东环大润发");
m3.put("city", "泰州市");
l.add(m3); List<Map<String, String>> countList = new ArrayList<Map<String,String>>();//用于存放最后的结果
for (int i = 0; i < l.size(); i++) {
String count = l.get(i).get("count");
String name = l.get(i).get("name");
String province = l.get(i).get("province");
String date = l.get(i).get("date");
String channel = l.get(i).get("channel");
String city = l.get(i).get("city"); int flag = 0;//0为新增数据，1为增加count
for (int j = 0; j < countList.size(); j++) {
String count_ = countList.get(j).get("count");
String name_ = countList.get(j).get("name");
String province_ = countList.get(j).get("province");
String date_ = countList.get(j).get("date");
String channel_ = l.get(j).get("channel");
String city_ = countList.get(j).get("city"); if (count.equals(count_)&&
name.equals(name_)&&
province.equals(province_)&&
date.equals(date_)&&
channel.equals(channel_)&&
city.equals(city_)) {
int sum = Integer.parseInt(l.get(i).get("count")) + Integer.parseInt(countList.get(j).get("count"));
countList.get(j).put("count", sum + "");
flag = 1;
continue;
}
}
if (flag == 0) {
countList.add(l.get(i));
}
}
for (Map<String, String> map : countList) {
System.out.println(map);
}
}
public class Test {
/**
* @param args
*/
public static void main(String[] args) {
List<Map<String, String>> list = new ArrayList<Map<String,String>>();
Map<String,String> map1 = new HashMap<String,String>();
map1.put("count", "1");
map1.put("name", "帮宝适纸尿裤L164 超薄干爽夏季透气专用婴儿尿不湿");
map1.put("province", "江苏省");
map1.put("date", "2014-09-23 10:13:39");
map1.put("channel", "东环大润发");
map1.put("city", "苏州市");
list.add(map1);
Map<String,String> map2 = new HashMap<String,String>();
map2.put("count", "1");
map2.put("name", "帮宝适纸尿裤L164 超薄干爽夏季透气专用婴儿尿不湿");
map2.put("province", "江苏省");
map2.put("date", "2014-09-23 10:13:39");
map2.put("channel", "东环大润发");
map2.put("city", "泰州市");
list.add(map2);
Map<String,String> map3 = new HashMap<String,String>();
map3.put("count", "1");
map3.put("name", "帮宝适纸尿裤L164 超薄干爽夏季透气专用婴儿尿不湿");
map3.put("province", "江苏省");
map3.put("date", "2014-09-23 10:13:39");
map3.put("channel", "东环大润发");
map3.put("city", "泰州市");
list.add(map3);
Map<String,String> map4 = new HashMap<String,String>();
map4.put("count", "1");
map4.put("name", "帮宝适纸尿裤L164 超薄干爽夏季透气专用婴儿尿不湿");
map4.put("province", "江苏省");
map4.put("date", "2014-09-23 10:13:39");
map4.put("channel", "东环大润发");
map4.put("city", "苏州市");
list.add(map4);
System.out.println(mergeList(list));
}
/**
* 合并相同的Map
* @param list
* @return
*/
public static List<Map<String,String>> mergeList(List<Map<String,String>> list){
List<Map<String,String>> retList = new ArrayList<Map<String,String>>();
for(int i=0;i<list.size();i++){
Map<String,String> map = list.get(i);
String name = map.get("name");
String city = map.get("city");
String count = map.get("count");
Map<String,String> newMap=isExistSame(i,name,city,count,list);
if(null==newMap){
retList.add(map);
}
else{
list.remove(map.get(i));
retList.add(newMap);
}
}
return retList;
}
private static Map<String,String> isExistSame(int i,String name,String city,String count,List<Map<String,String>> list){
Map<String,String> newMap = null;
for(int j=i+1;j<list.size();j++){
Map<String,String> innerMap = list.get(j);
String name1 = innerMap.get("name");
String city1 = innerMap.get("city");
String count1 = innerMap.get("count");
if(name.equals(name1)&&city.equals(city1)){
newMap = new HashMap<String,String>();
newMap.put("count", ""+(Integer.parseInt(count)+Integer.parseInt(count1)));
Iterator<String> keyIterator = innerMap.keySet().iterator();
while(keyIterator.hasNext()){
String key = keyIterator.next();
if(!key.equals("count")){
newMap.put(key, innerMap.get(key));
}
}
list.remove(j);
}
}
return newMap;
}
}
ublic static void main(String[] args) {
List<Map<String, String>> list = new ArrayList<Map<String,String>>();
boolean m = true;
for(int i=0;i<10000;i++){
HashMap<String, String> map = new HashMap<String, String>();
map.put("count", "1");
map.put("name", "帮宝适纸尿裤L164 超薄干爽夏季透气专用婴儿尿不湿");
map.put("province", "江苏省");
map.put("date", "2014-09-23 10:13:39");
map.put("channel", "东环大润发");
map.put("city", m ? "苏州市":"泰州市");
m = !m;
list.add(map);
}
System.out.println(System.currentTimeMillis());
for(int i=list.size();--i>-1;){
Map<String, String> src = list.get(i);
int same = 0;
for(int j=i-1;j>-1;j--){
Map<String, String> tar = list.get(j);
if(equals(src, tar)){
int count = Integer.parseInt(src.get("count"))
+Integer.parseInt(tar.get("count"));
src.put("count", count+"");
list.remove(j);
same++;
}
}
i -=same;
}
System.out.println(list);
System.out.println(System.currentTimeMillis());
}
public static boolean equals(Map<String, String> src,Map<String, String> tar){
Set<Entry<String,String>> entrySet = src.entrySet();
String srcCount = src.remove("count");//count不参与比较
String srcValue = null,tarValue = null;
for (Iterator<Entry<String,String>> it = entrySet.iterator(); it.hasNext();) {
Entry<String, String> entry = it.next();
srcValue = entry.getValue();
tarValue = tar.get(entry.getKey());
if(srcValue.length()!=tarValue.length()||!srcValue.equals(tarValue)){
src.put("count", srcCount);
return false;
}
}
src.put("count", srcCount);
return true;
}