/**
* @param String keywords
* @return Term term 根据查询关键词查找相关的查询扩展信息
* 返回形式：term:{keyWords:"",eventId:{1,2,3,……},newsId:{1,2,3,……}，expansionTerm:{"","","",……}}
*/
public Expansion getExpansionByKeywords(String keywords) {
Expansion expansion = new Expansion();
init();
Connection conn = null;
PreparedStatement pstmt = null;
ResultSet rs = null;
try {
conn = dataSource.getConnection();
pstmt = conn.prepareStatement(SQL_SELECT_EXPANSION_BY_KEYWORDS);
pstmt.setString(1, keywords);
if (pstmt.execute()) {
rs = pstmt.getResultSet();
if (rs.next()) {
expansion.setTerm(keywords);
if (rs.getString("eventsId") != null) {
String eventsIdString[] = rs.getString("eventsId").split(",");
int[] eventsId = new int[eventsIdString.length];
for (int i = 0; i < eventsIdString.length; i++) {
eventsId[i] = Integer.parseInt(eventsIdString[i]);
expansion.addEventId(eventsId[i]);
} // for
}
// 获得所有的news
String newsIdString[] = rs.getString("newsId").split(",");
int[] newsId = new int[newsIdString.length];
for (int i = 0; i < newsIdString.length; i++) {
newsId[i] = Integer.parseInt(newsIdString[i]);
expansion.addNewsId(newsId[i]);
} // for
// 获得所有的扩展词
String[] expansionTerms = rs.getString("expansionTerms").split(",");
for (String expansionTerm : expansionTerms) {
expansion.addExpansionTerms(expansionTerm);
}
} // if
else {
expansion = null;
} // 如果数据库中不存在该扩展，则返回空
} // try
} catch (SQLException e) {
e.printStackTrace();
} finally {
try {
if (rs != null) rs.close();
if (pstmt != null) pstmt.close();
if (conn != null) conn.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
return expansion;
}
/** @param Term 将单个的扩展存入数据库 */
public void insertExpansion(Expansion expansion) {
init();
if (expansion == null) return;
// 如果数据库中已存在，则只进行更新操作
if (getExpansionByKeywords(expansion.getTerm()) != null) updateExpansion(expansion);
// 若不存在，则进行插入操作
else {
Connection conn = null;
PreparedStatement pstmt = null;
ResultSet rs = null;
try {
conn = dataSource.getConnection();
pstmt = conn.prepareStatement(SQL_INSERT_EXPANSION, Statement.RETURN_GENERATED_KEYS);
pstmt.setString(1, expansion.getTerm());
/*将与查询词相关的事件id以字符串的形式存储，中间用‘，’隔开，以防止过度冗余，存储形式如"1,2,3",说明与该词相关的事件是事件1、事件2和事件3，
* 并且对于事件只存id号，如果需要其他详细信息，可以根据id号进行进一步的查询 */
String EventsIdString = intArrayToString(expansion.getEventId());
pstmt.setString(2, EventsIdString);
/*对于新闻的存储方法同事件的存储方式*/
String NewsIdString = intArrayToString(expansion.getNewsId());
pstmt.setString(3, NewsIdString);
String ExpansionTermString = stringArrayToString(expansion.getExpansionTerms());
pstmt.setString(4, ExpansionTermString);
pstmt.executeUpdate();
} catch (SQLException e) {
e.printStackTrace();
} finally {
try {
if (rs != null) rs.close();
if (pstmt != null) pstmt.close();
if (conn != null) conn.close();
} catch (SQLException e) {
e.printStackTrace();
}
} // finally
} // else
}
/**
* @param Term term
* 此方法实现对数据库原有的扩展进行更新，即如果数据库中已经存在关于某个查询关键词的扩展，并且要插入的expansion的关键词与该词相同，则将插入操作改为更新操作
*/
public void updateExpansion(Expansion expansion) {
init();
Expansion existExpansion = getExpansionByKeywords(expansion.getTerm());
// 将数据库中已有的扩展和该扩展合并
if (existExpansion.getEventId() == null || existExpansion.getEventId().isEmpty()) {
existExpansion.addEventId(expansion.getEventId());
} else {
for (int eid : expansion.getEventId()) {
if (!existExpansion.getEventId().contains(eid)) existExpansion.addEventId(eid);
}
}
for (int nid : expansion.getNewsId()) {
if (!existExpansion.getNewsId().contains(nid)) existExpansion.addNewsId(nid);
}
for (String expansionTerm : expansion.getExpansionTerms()) {
if (!existExpansion.getExpansionTerms().contains(expansionTerm))
existExpansion.addExpansionTerms(expansionTerm);
}
Connection conn = null;
PreparedStatement pstmt = null;
ResultSet rs = null;
try {
conn = dataSource.getConnection();
pstmt = conn.prepareStatement(SQL_UPDATE_EXPANSION);
pstmt.setString(1, intArrayToString(existExpansion.getEventId()));
pstmt.setString(2, intArrayToString(existExpansion.getNewsId()));
pstmt.setString(3, stringArrayToString(existExpansion.getExpansionTerms()));
pstmt.setString(4, existExpansion.getTerm());
pstmt.executeUpdate();
} catch (SQLException e) {
e.printStackTrace();
} finally {
try {
if (rs != null) rs.close();
if (pstmt != null) pstmt.close();
if (conn != null) conn.close();
} catch (SQLException e) {
e.printStackTrace();
}
} // finally
}