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java使用list实现数据库的like功能

程序员文章站 2024-02-27 20:18:21
使用list实现类似数据库的like,between,精确查找方法 复制代码 代码如下:public final class commonlocalquery

使用list实现类似数据库的like,between,精确查找方法

复制代码 代码如下:

public final class commonlocalquery<t extends map<string, object>> {

 //传入数据查询后返回list, 第一个参数:被查询列表,第二个参数:查询条件
 public list<t> querydata(final list<t> malllist, final hashhashmap<policy, string, string> map) {

  if(malllist == null | map == null) {
   return new arraylist<t>();
  }

  if(malllist.isempty()) {
   return malllist;
  }

  /* 根据实际需要找出符合的查询条件 */
  set<policy> key1 = map.getfirstkeys();
  for (policy policy : key1) {
   concurrenthashmap<string, string> tempmap = map.get(policy);
   set<string> key2 = tempmap.keyset();
   for (string key : key2) {
    if(key.startswith("-") || tempmap.get(key) == null ||
      (tempmap.get(key) != null && tempmap.get(key).equals(""))) {
     tempmap.remove(key);
    }
   }
  }
// 责任链设计模式进行查找
  filter filternormal, filterbetween, filterfuzzy;
  filternormal = new filternormal();
  filterbetween = new filterbetween();
  filterfuzzy = new filterfuzzy();
  filternormal.setfilter(filterbetween);
  filterbetween.setfilter(filterfuzzy);
  set<policy> endkey1 = map.getfirstkeys();
  list<t> listresult = new arraylist<t>();
  for (t resmap : malllist) {
   for (policy policy : endkey1) {
    concurrenthashmap<string, string> querymap = map.get(policy);
    if (filternormal.dofilter(resmap, policy, querymap) && listresult.contains(resmap)) {
     listresult.add(resmap);
    }
   }
  }
  return listresult;
 }

 public static enum policy { normal, between, fuzzy }
}

/*======== 责任链抽象类 ======*/
abstract class filter {

 filter filter;

 public void setfilter(filter filter) {
  this.filter = filter;
 }

 public filter getfilter() {
  return filter;
 }

 abstract boolean dofilter(map<string, object> resmap, policy policy, map<string, string> querymap);
}
//精确查找方式
class filternormal extends filter {

 @override
 boolean dofilter(map<string, object> resmap, policy policy, map<string, string> querymap) {
  // todo auto-generated method stub
  if (policy.name().equalsignorecase(policy.normal.name())) {
   iterator<entry<string, string>> iterator = querymap.entryset().iterator();
   while(iterator.hasnext()) {
    entry<string, string> entry = iterator.next();
    if(!resmap.get(entry.getkey()).tostring().contains(entry.getvalue())) {
     return false;
    }
   }
  } else if (filter != null) {
   return filter.dofilter(resmap, policy, querymap);
  }
  return true;
 }
}
//between查找方式
class filterbetween extends filter {

 @override
 boolean dofilter(map<string, object> resmap, policy policy, map<string, string> querymap) {
  // todo auto-generated method stub
  if (policy.name().equalsignorecase(policy.between.name())) {
   iterator<entry<string, string>> iterator = querymap.entryset().iterator();
   while(iterator.hasnext()) {
    entry<string, string> entry = iterator.next();
    if(!pattern.matches(".+?φ.+?", entry.getvalue()))
     throw new unknownerror("values should be .+?φ.+? pattern");
    string firstvalue = entry.getvalue().split("φ")[0];
    string secondvalue = entry.getvalue().split("φ")[1];
    if(resmap.get(entry.getkey()).tostring().compareto(firstvalue) < 0
      || resmap.get(entry.getkey()).tostring().compareto(secondvalue) > 0) {
     return false;
    }
   }
  } else if (filter != null) {
   return filter.dofilter(resmap, policy, querymap);
  }
  return true;
 }
}
//模糊查找方式
class filterfuzzy extends filter {

 @override
 boolean dofilter(map<string, object> resmap, policy policy, map<string, string> querymap) {
  // todo auto-generated method stub
  if (policy.name().equalsignorecase(policy.fuzzy.name())) {
   string tempstr = resmap.values().tostring().replace(" ", "").replace(",", "");
   iterator<entry<string, string>> iterator = querymap.entryset().iterator();
   while(iterator.hasnext()) {
    entry<string, string> entry = iterator.next();
    if(tempstr.substring(1, tempstr.length()-1).contains(entry.getvalue())) {
     return true;
    }
   }
  } else if (filter != null) {
   return filter.dofilter(resmap, policy, querymap);
  }
  return true;
 }
}


//帮助类实现 k1-k2-v
public class hashhashmap<k1, k2, v> {

    private concurrenthashmap<k1, concurrenthashmap<k2, v>> k1k2vmap;

    public hashhashmap() {
        this.k1k2vmap = new concurrenthashmap<k1, concurrenthashmap<k2, v>>();
    }

    public void put(k1 key1, k2 key2, v value) {
        if (k1k2vmap.containskey(key1)) {
            concurrenthashmap<k2, v> k2vmap = k1k2vmap.get(key1);
            k2vmap.put(key2, value);
        } else {
            concurrenthashmap<k2, v> k2vmap = new concurrenthashmap<k2, v>();
            k2vmap.put(key2, value);
            k1k2vmap.put(key1, k2vmap);
        }
    }

    public set<k1> getfirstkeys() {
        return k1k2vmap.keyset();
    }

    public v get(k1 key1, k2 key2) {
        concurrenthashmap<k2, v> k2_v = k1k2vmap.get(key1);
        return k2_v == null ? null : k2_v.get(key2);
    }

    public concurrenthashmap<k2, v> get(k1 key1) {
        return k1k2vmap.get(key1);
    }

    public boolean containskey(k1 key1, k2 key2) {
        if (k1k2vmap.containskey(key1)) {
            return k1k2vmap.get(key1).containskey(key2);
        }
        return false;
    }

    public boolean containskey(k1 key1) {
        return k1k2vmap.containskey(key1);
    }

    public void clear() {
        if (k1k2vmap.size() > 0) {
            for (concurrenthashmap<k2, v> k2vmap : k1k2vmap.values()) {
                k2vmap.clear();
            }
            k1k2vmap.clear();
        }
    }
}

//具体使用方式
hashhashmap<policy, string, string> map = new hashhashmap<commonlocalquery.policy, string, string>();
  for(int i = 0; i < querykey.length; i++){
   map.put(policy.normal, querykey[i], queryvalue[i]);
  }
list<map<string, object>> mtemplist = new commonlocalquery<hashmap<string, object>>(