我有一个允许用户选择某些关键字的应用程序，然后该应用程序会侦听包含这些关键字的推文并将其存储在数据库中。
对于给定用户，他们有一个关键字列表。我想要做的是通过计算在某一天/每月发生的关键字的推文数量来获得关于每个关键字在给定日期，月份等方面的执行情况的统计信息。
public class Person extends Model {
@id
long id;
@ManyToMany
List<Keywords> keywords = new ArrayList();
}
public class Keyword extends Model {
@Id
int id;
String keyword;
@ManyToMany
public List<Tweet> tweets = new ArrayList();
}
public class Tweet extends Model {
@Id
int id;
TimeStamp datetime;
}
我认为最好的方法是Tweet.find - where keyword = kw and date＆gt; d--但我不知道该怎么做。我应该使用fetch吗？这是下面普通SQL中的类似查询。
select datetime, count(*) from tweet t left outer join keyword_tweet on t.id=keyword_tweet.tweet_id group by cast(t.datetime as date) having t.datetime > '2014-02-02';
+---------------------+----------+
| datetime | count(*) |
+---------------------+----------+
| 2014-02-02 13:27:45 | 1 |
| 2014-02-08 05:14:04 | 2 |
| 2014-02-09 08:34:31 | 1 |
| 2014-02-12 12:42:02 | 1 |
| 2014-02-13 06:00:09 | 2 |
| 2014-02-14 00:47:04 | 2 |
| 2014-02-15 07:26:30 | 6 |
| 2014-02-16 01:00:00 | 21 |
| 2014-02-17 00:06:50 | 916 |
| 2014-02-18 18:08:56 | 1 |
| 2014-02-19 01:28:40 | 1 |
| 2014-02-24 16:45:11 | 1 |
| 2014-02-26 14:43:54 | 4 |
| 2014-02-27 08:24:09 | 9 |
| 2014-02-28 05:08:16 | 411 |
+---------------------+----------+
因此，请从推文中选择（推文ID在用户关键字列表中）
我也想分组：
cast(t.datetime as date)
并且
date > 2014-02-02 //example date
对某些查询。谢谢你的帮助!!
答案 0 :(得分：1)
这可能不是您正在寻找的，但也许它可以帮助您入门。有以下方法可以在下面的Tweet.find.where（）中进行连接或使用查询，而不是使用Person中的关键字列表，这可能更容易。 git hub examples中有一些加入，但它们有点旧
package models.test;
import play.db.ebean.Model;
import javax.persistence.*;
import java.util.ArrayList;
import java.util.List;
/**
* Created by aakture on 3/7/14.
*/
@Entity
public class Person extends Model {
@Id
long id;
@OneToMany(cascade = CascadeType.ALL)
List<Keyword> keywords = new ArrayList();
public long getId() {
return id;
}
public void setId(long id) {
this.id = id;
}
public List<Keyword> getKeywords() {
return keywords;
}
public void setKeywords(List<Keyword> keywords) {
this.keywords = keywords;
}
public static Finder<Integer, Person> find = new Finder<Integer, Person>(
Integer.class, Person.class);
}
package models.test;
import play.db.ebean.Model;
import javax.persistence.Entity;
import javax.persistence.Id;
@Entity
public class Keyword extends Model {
@Id
Integer id;
String text;
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getText() {
return text;
}
public void setText(String text) {
this.text = text;
}
public static Finder<Integer, Keyword> find = new Finder<Integer, Keyword>(
Integer.class, Keyword.class);
}
package models.test;
import play.db.ebean.Model;
import javax.persistence.*;
import java.sql.Date;
@Entity
public class Tweet extends Model {
@Id
Integer id;
Date datetime;
@OneToOne
Keyword keyword;
public void setId(Integer id) {
this.id = id;
}
public Keyword getKeyword() {
return keyword;
}
public void setKeyword(Keyword keyword) {
this.keyword = keyword;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public Date getDatetime() {
return datetime;
}
public void setDatetime(Date datetime) {
this.datetime = datetime;
}
public static Finder<Integer, Tweet> find = new Finder<Integer, Tweet>(
Integer.class, Tweet.class);
}
@Test
public void testTweets() {
List<Keyword> keywordList = new ArrayList<Keyword>();
Keyword keyword = new Keyword();
keyword.setText("hello");
keywordList.add(keyword);
keyword = new Keyword();
keyword.setText("world");
keywordList.add(keyword);
Person person = new Person();
person.setKeywords(keywordList);
person.save();
keyword = Keyword.find.where().eq("text", "hello").findUnique();
log.info("keywords " + keyword);
java.sql.Date now = new java.sql.Date(new Date().getTime());
for(int i = 0; i < 10; i++) {
Tweet tweet = new Tweet();
tweet.setKeyword(keyword);
tweet.setDatetime(now);
tweet.save();
}
log.info("now is " + now.getTime());
Calendar cal = Calendar.getInstance();
cal.add(Calendar.DAY_OF_YEAR, -7);
java.sql.Date oneHourAgo = new java.sql.Date(cal.getTimeInMillis());
log.info("oneHourAgo is " + oneHourAgo.getTime());
List<Keyword> personsKeywords = person.getKeywords();
List<String> keyWordsStringList = new ArrayList<String>();
for(Keyword kw : keywordList) {
keyWordsStringList.add(kw.getText());
}
List<Tweet> tweets = Tweet.find.where().and(Expr.in("keyword.text", keyWordsStringList), Expr.gt("datetime", oneHourAgo)).findList();
log.info("tweets has " + tweets.size());
}