下面列出了java.sql.ResultSet#isBeforeFirst ( ) 实例代码，或者点击链接到github查看源代码，也可以在右侧发表评论。
private void createOutcomeIndex() {
try {
final String sqlString = "SELECT * FROM INFORMATION_SCHEMA.STATISTICS WHERE TABLE_CATALOG = 'def' AND TABLE_SCHEMA = DATABASE() AND TABLE_NAME = \"game\" AND INDEX_NAME = \"OutcomeIndex\"";
final Statement gameStatement = this.dbConnection.createStatement();
gameStatement.execute(sqlString);
final ResultSet resultSet = gameStatement.getResultSet();
if(!resultSet.isBeforeFirst() ) {
final Statement indexStatement = this.dbConnection.createStatement();
indexStatement.execute("CREATE INDEX OutcomeIndex on Game(outcome);\n");
indexStatement.close();
}
gameStatement.close();
}
catch (final SQLException e) {
e.printStackTrace();
}
}
public String getLastEmailByDeviceId(String deviceId) throws SQLException {
String selectStatementString = "SELECT * FROM " + TABLE_DEVICES + " WHERE " + COLUMN_DEVICE_ID + " = ?";
PreparedStatement findStatement = getServerDatabaseConnection().prepareStatement(selectStatementString);
findStatement.setString(1, deviceId);
ResultSet resultSet = findStatement.executeQuery();
if (!resultSet.isBeforeFirst()){
resultSet.close();
findStatement.close();
return null;
}
String deviceEmail = resultSet.getString(COLUMN_DEVICE_LAST_EMAIL);
resultSet.close();
findStatement.close();
return deviceEmail;
}
public String getNameByDeviceId(String deviceId) throws SQLException {
String selectStatementString = "SELECT * FROM " + TABLE_DEVICES + " WHERE " + COLUMN_DEVICE_ID + " = ?";
PreparedStatement findStatement = getServerDatabaseConnection().prepareStatement(selectStatementString);
findStatement.setString(1, deviceId);
ResultSet resultSet = findStatement.executeQuery();
if (!resultSet.isBeforeFirst()){
resultSet.close();
findStatement.close();
return null;
}
String deviceName = resultSet.getString(COLUMN_DEVICE_NAME);
resultSet.close();
findStatement.close();
return deviceName;
}
private static void fetchSkillbooksFromReactors() {
Connection con = null;
try {
con = DatabaseConnection.getConnection();
PreparedStatement ps = con.prepareStatement("SELECT itemid FROM reactordrops WHERE itemid >= ? AND itemid < ?;");
ps.setInt(1, skillbookMinItemid);
ps.setInt(2, skillbookMaxItemid);
ResultSet rs = ps.executeQuery();
if (rs.isBeforeFirst()) {
while(rs.next()) {
foundSkillbooks.put(rs.getInt("itemid"), SkillBookEntry.REACTOR);
}
}
rs.close();
ps.close();
con.close();
} catch (SQLException sqle) {
sqle.printStackTrace();
}
}
/** Create a table from a {@link ResultSet}. */
public static String fromResultSet(ResultSet resultSet) throws SQLException {
if (resultSet == null) throw new NullPointerException("resultSet == null");
if (!resultSet.isBeforeFirst()) throw new IllegalStateException("Result set not at first.");
List<String> headers = new ArrayList<>();
ResultSetMetaData resultSetMetaData = resultSet.getMetaData();
int columnCount = resultSetMetaData.getColumnCount();
for (int column = 0; column < columnCount; column++) {
headers.add(resultSetMetaData.getColumnName(column + 1));
}
List<String[]> data = new ArrayList<>();
while (resultSet.next()) {
String[] rowData = new String[columnCount];
for (int column = 0; column < columnCount; column++) {
rowData[column] = resultSet.getString(column + 1);
}
data.add(rowData);
}
String[] headerArray = headers.toArray(new String[headers.size()]);
String[][] dataArray = data.toArray(new String[data.size()][]);
return FlipTable.of(headerArray, dataArray);
}
public static Client getClientWithAlias(String alias){
try(Connection con = connect();
PreparedStatement pstmt = con.prepareStatement(selectClientWithAlias)) {
pstmt.setString(1, alias);
ResultSet rs = pstmt.executeQuery();
if (!rs.isBeforeFirst() ) {
return null;
}
return new Client(
rs.getString(clientName),
rs.getString(alias),
rs.getString(clientGUID),
Client.Role.prestigeToRole(rs.getInt(clientRole)
));
} catch (SQLException e) {
e.printStackTrace();
}
return null;
}
public Message getLastNotNullMessageFromChat(ChatBase chat) throws SQLException {
String selectStatementString = "SELECT * FROM " + CHAT_MESSAGE_JOIN_TABLE
+ " INNER JOIN " + MESSAGE_TABLE + " ON " + CHAT_MESSAGE_JOIN_TABLE + "." + COLUMN_CHAT_MESSAGE_MESSAGE_ID + " = " + MESSAGE_TABLE + "." + COLUMN_MESSAGE_ROWID
+ " WHERE " + COLUMN_CHAT_MESSAGE_CHAT_ID + " = ? "
+ " AND " + MESSAGE_TABLE + "." + COLUMN_MESSAGE_TEXT + " IS NOT NULL "
+ " ORDER BY " + COLUMN_CHAT_MESSAGE_MESSAGE_ID + " DESC LIMIT 1";
PreparedStatement selectStatement = getDatabaseManager().getChatDatabaseConnection().prepareStatement(selectStatementString);
selectStatement.setLong(1, chat.getRowID());
ResultSet resultSet = selectStatement.executeQuery();
if (!resultSet.isBeforeFirst()){
resultSet.close();
selectStatement.close();
return null;
}
long rowID = resultSet.getLong(COLUMN_CHAT_MESSAGE_MESSAGE_ID);
Message message = getMessageByRow(rowID);
resultSet.close();
selectStatement.close();
return message;
}
public Attachment getAttachmentByRow(long rowID) throws SQLException {
String selectStatementString = "SELECT * FROM " + ATTACHMENT_TABLE + " WHERE " + COLUMN_ATTACHMENT_ROWID + " = ?";
PreparedStatement selectStatement = getDatabaseManager().getChatDatabaseConnection().prepareStatement(selectStatementString);
selectStatement.setLong(1, rowID);
ResultSet resultSet = selectStatement.executeQuery();
if (!resultSet.isBeforeFirst()){
resultSet.close();
selectStatement.close();
return null;
}
Attachment attachment = buildAttachment(resultSet);
resultSet.close();
selectStatement.close();
return attachment;
}
public Handle getHandleByRow(long rowID) throws SQLException {
String selectStatementString = "SELECT * FROM " + HANDLE_TABLE + " WHERE " + COLUMN_HANDLE_ROWID + " = ?";
PreparedStatement selectStatement = getDatabaseManager().getChatDatabaseConnection().prepareStatement(selectStatementString);
selectStatement.setLong(1, rowID);
ResultSet resultSet = selectStatement.executeQuery();
if (!resultSet.isBeforeFirst()){
resultSet.close();
selectStatement.close();
return null;
}
Handle handle = buildHandle(resultSet);
resultSet.close();
selectStatement.close();
return handle;
}
/**
* Function to populate Meta Data.
* @param columnNamesSet is a set having column names given by the user
* @throws SQLException
*/
protected void populateColumnDataTypes(HashSet<String> columnNamesSet) throws SQLException
{
ResultSet rsColumns;
DatabaseMetaData meta = store.getConnection().getMetaData();
rsColumns = meta.getColumns(null, null, getTablename(), null);
/**Identifiers (table names, column names etc.) may be stored internally in either uppercase or lowercase.**/
if (!rsColumns.isBeforeFirst()) {
rsColumns = meta.getColumns(null, null, getTablename().toUpperCase(), null);
if (!rsColumns.isBeforeFirst()) {
rsColumns = meta.getColumns(null, null, getTablename().toLowerCase(), null);
if (!rsColumns.isBeforeFirst()) {
throw new RuntimeException("Table name not found");
}
}
}
boolean readAllColumns = columnNamesSet.size() == 0 ? true : false;
int remainingColumns = columnNamesSet.size();
while (rsColumns.next()) {
if (readAllColumns || remainingColumns > 0) {
if (readAllColumns || columnNamesSet.contains(rsColumns.getString("COLUMN_NAME").toUpperCase())) {
columnNames.add(rsColumns.getString("COLUMN_NAME"));
columnNullabilities.add(rsColumns.getInt("NULLABLE"));
columnDataTypes.add(rsColumns.getInt("DATA_TYPE"));
remainingColumns--;
}
} else {
break;
}
}
}
private boolean resultSetHasRows(ResultSet resultSet) {
boolean hasRows = false;
if (resultSet != null) {
try {
// true if the cursor is before the first row; false if the
// cursor is at any other position or the result set contains no
// rows }
hasRows = resultSet.isBeforeFirst();
} catch (SQLException e) {
}
}
return hasRows;
}
@Test(expected = SQLFeatureNotSupportedException.class)
public void assertIsBeforeFirst() throws SQLException {
for (ResultSet each : resultSets) {
each.isBeforeFirst();
}
}
public Message getMessageByRow(long rowID) throws SQLException {
String selectStatementString = "SELECT * FROM " + MESSAGE_TABLE + " WHERE " + COLUMN_MESSAGE_ROWID + " = ?";
PreparedStatement selectStatement = getDatabaseManager().getChatDatabaseConnection().prepareStatement(selectStatementString);
selectStatement.setLong(1, rowID);
ResultSet resultSet = selectStatement.executeQuery();
if (!resultSet.isBeforeFirst()){
resultSet.close();
selectStatement.close();
return null;
}
Handle handle = getHandleByRow(resultSet.getLong(COLUMN_MESSAGE_HANDLE_ID));
long messageRow = resultSet.getLong(COLUMN_MESSAGE_ROWID);
String selectChatMessageStatementString = "SELECT * FROM " + CHAT_MESSAGE_JOIN_TABLE + " WHERE " + COLUMN_CHAT_MESSAGE_MESSAGE_ID + " = ?";
PreparedStatement selectChatMessageStatement = getDatabaseManager().getChatDatabaseConnection().prepareStatement(selectChatMessageStatementString);
selectChatMessageStatement.setLong(1, messageRow);
ResultSet resultChatMessageSet = selectChatMessageStatement.executeQuery();
ChatBase chat;
try {
long theResultInt = resultChatMessageSet.getLong(COLUMN_CHAT_MESSAGE_CHAT_ID);
chat = getChatByRow(theResultInt);
}catch(Exception ex){
return null;
}
List<Attachment> attachments = new ArrayList<>();
String selectMessageAttachmentString = "SELECT * FROM " + MESSAGE_ATTACHMENT_TABLE + " WHERE " + COLUMN_MESSAGE_ATTACHMENT_MESSAGE_ID + " = ?";
PreparedStatement selectMessageAttachmentStatement = getDatabaseManager().getChatDatabaseConnection().prepareStatement(selectMessageAttachmentString);
selectMessageAttachmentStatement.setLong(1, messageRow);
boolean isResultSet = selectMessageAttachmentStatement.execute();
while(true) {
if(isResultSet) {
ResultSet theResultSet = selectMessageAttachmentStatement.getResultSet();
while(theResultSet.next()) {
long resultInt = theResultSet.getLong(COLUMN_MESSAGE_ATTACHMENT_ATTACHMENT_ID);
attachments.add(getAttachmentByRow(resultInt));
}
theResultSet.close();
} else {
if(selectMessageAttachmentStatement.getUpdateCount() == -1) {
break;
}
}
isResultSet = selectMessageAttachmentStatement.getMoreResults();
}
Message message = buildMessage(resultSet, chat, handle, attachments);
resultSet.close();
resultChatMessageSet.close();
selectStatement.close();
selectChatMessageStatement.close();
selectMessageAttachmentStatement.close();
return message;
}
@Test(expected = SQLFeatureNotSupportedException.class)
public void assertIsBeforeFirst() throws SQLException {
for (ResultSet each : resultSets) {
each.isBeforeFirst();
}
}
/**
* Loads a single logical row from the result set moving forward. This is the
* processing used from the ScrollableResults where there were collection fetches
* encountered; thus a single logical row may have multiple rows in the underlying
* result set.
*
* @param resultSet The result set from which to do the load.
* @param session The session from which the request originated.
* @param queryParameters The query parameters specified by the user.
* @param returnProxies Should proxies be generated
* @return The loaded "row".
* @throws HibernateException
*/
public Object loadSequentialRowsForward(
final ResultSet resultSet,
final SessionImplementor session,
final QueryParameters queryParameters,
final boolean returnProxies) throws HibernateException {
// note that for sequential scrolling, we make the assumption that
// the first persister element is the "root entity"
try {
if ( resultSet.isAfterLast() ) {
// don't even bother trying to read further
return null;
}
if ( resultSet.isBeforeFirst() ) {
resultSet.next();
}
// We call getKeyFromResultSet() here so that we can know the
// key value upon which to perform the breaking logic. However,
// it is also then called from getRowFromResultSet() which is certainly
// not the most efficient. But the call here is needed, and there
// currently is no other way without refactoring of the doQuery()/getRowFromResultSet()
// methods
final EntityKey currentKey = getKeyFromResultSet(
0,
getEntityPersisters()[0],
null,
resultSet,
session
);
return sequentialLoad( resultSet, session, queryParameters, returnProxies, currentKey );
}
catch ( SQLException sqle ) {
throw JDBCExceptionHelper.convert(
factory.getSQLExceptionConverter(),
sqle,
"could not perform sequential read of results (forward)",
getSQLString()
);
}
}
/**
* Applies any database updates by comparing the current version to the
* stored version. Does nothing if tables have not been created.
*/
private static void updateDatabase() throws Exception
{
try (Statement stmt = connection.createStatement()) {
int version = 0;
// if 'info' table does not exist, assume version 0 and apply all updates
String sql = "SELECT name FROM sqlite_master WHERE type = 'table' AND name = 'info'";
ResultSet rs = stmt.executeQuery(sql);
boolean infoExists = rs.isBeforeFirst();
rs.close();
if (!infoExists) {
// if 'scores' table also does not exist, databases not yet created
sql = "SELECT name FROM sqlite_master WHERE type = 'table' AND name = 'scores'";
ResultSet scoresRS = stmt.executeQuery(sql);
boolean scoresExists = scoresRS.isBeforeFirst();
scoresRS.close();
if (!scoresExists)
return;
} else {
// try to retrieve stored version
sql = "SELECT value FROM info WHERE key = 'version'";
ResultSet versionRS = stmt.executeQuery(sql);
String versionString = (versionRS.next()) ? versionRS.getString(1) : "0";
versionRS.close();
try {
version = Integer.parseInt(versionString);
} catch (NumberFormatException e) {}
}
// database versions match
if (version >= DATABASE_VERSION)
return;
// apply updates
for (String query : getUpdateQueries(version))
stmt.executeUpdate(query);
// update version
if (infoExists) {
PreparedStatement ps = connection.prepareStatement("REPLACE INTO info (key, value) VALUES ('version', ?)");
ps.setString(1, Integer.toString(DATABASE_VERSION));
ps.executeUpdate();
ps.close();
}
}
}
public ChatBase getChatByRow(long rowID) throws SQLException {
String selectChatStatementString = "SELECT * FROM " + CHAT_TABLE + " WHERE " + COLUMN_CHAT_ROWID + " = ?";
PreparedStatement selectChatStatement = getDatabaseManager().getChatDatabaseConnection().prepareStatement(selectChatStatementString);
selectChatStatement.setLong(1, rowID);
ResultSet chatResultSet = selectChatStatement.executeQuery();
if (!chatResultSet.isBeforeFirst()){
chatResultSet.close();
selectChatStatement.close();
return null;
}
List<Handle> handles = new ArrayList<>();
String selectChatHandleStatementString = "SELECT * FROM " + CHAT_HANDLES_TABLE + " WHERE " + COLUMN_CHAT_HANDLE_CHAT_ID + " = ?";
PreparedStatement selectChatHandleStatement = getDatabaseManager().getChatDatabaseConnection().prepareStatement(selectChatHandleStatementString);
selectChatHandleStatement.setLong(1, rowID);
boolean isResultSet = selectChatHandleStatement.execute();
while(true) {
if(isResultSet) {
ResultSet resultSet = selectChatHandleStatement.getResultSet();
while(resultSet.next()) {
long resultInt = resultSet.getLong(COLUMN_CHAT_HANDLE_HANDLE_ID);
handles.add(getHandleByRow(resultInt));
}
resultSet.close();
} else {
if(selectChatHandleStatement.getUpdateCount() == -1) {
break;
}
}
isResultSet = selectChatHandleStatement.getMoreResults();
}
ChatBase chat = buildChat(chatResultSet, handles);
chatResultSet.close();
selectChatStatement.close();
selectChatHandleStatement.close();
return chat;
}
public ChatBase getChatByGuid(String guid) throws SQLException {
String selectChatStatementString = "SELECT * FROM " + CHAT_TABLE + " WHERE " + COLUMN_CHAT_GUID + " = ?";
PreparedStatement selectChatStatement = getDatabaseManager().getChatDatabaseConnection().prepareStatement(selectChatStatementString);
selectChatStatement.setString(1, guid);
ResultSet chatResultSet = selectChatStatement.executeQuery();
if (!chatResultSet.isBeforeFirst()){
chatResultSet.close();
selectChatStatement.close();
return null;
}
List<Handle> handles = new ArrayList<>();
String selectChatHandleStatementString = "SELECT * FROM " + CHAT_HANDLES_TABLE + " WHERE " + COLUMN_CHAT_HANDLE_CHAT_ID + " = ?";
PreparedStatement selectChatHandleStatement = getDatabaseManager().getChatDatabaseConnection().prepareStatement(selectChatHandleStatementString);
selectChatHandleStatement.setLong(1, chatResultSet.getLong(COLUMN_CHAT_ROWID));
boolean isResultSet = selectChatHandleStatement.execute();
while(true) {
if(isResultSet) {
ResultSet resultSet = selectChatHandleStatement.getResultSet();
while(resultSet.next()) {
long resultInt = resultSet.getLong(COLUMN_CHAT_HANDLE_HANDLE_ID);
handles.add(getHandleByRow(resultInt));
}
resultSet.close();
} else {
if(selectChatHandleStatement.getUpdateCount() == -1) {
break;
}
}
isResultSet = selectChatHandleStatement.getMoreResults();
}
ChatBase chat = buildChat(chatResultSet, handles);
chatResultSet.close();
selectChatStatement.close();
selectChatHandleStatement.close();
return chat;
}
public ChatBase getChatByGroupID(String groupID) throws SQLException {
String selectChatStatementString = "SELECT * FROM " + CHAT_TABLE + " WHERE " + COLUMN_CHAT_GROUP_ID + " = ?";
PreparedStatement selectChatStatement = getDatabaseManager().getChatDatabaseConnection().prepareStatement(selectChatStatementString);
selectChatStatement.setString(1, groupID);
ResultSet chatResultSet = selectChatStatement.executeQuery();
if (!chatResultSet.isBeforeFirst()){
chatResultSet.close();
selectChatStatement.close();
return null;
}
List<Handle> handles = new ArrayList<>();
String selectChatHandleStatementString = "SELECT * FROM " + CHAT_HANDLES_TABLE + " WHERE " + COLUMN_CHAT_HANDLE_CHAT_ID + " = ?";
PreparedStatement selectChatHandleStatement = getDatabaseManager().getChatDatabaseConnection().prepareStatement(selectChatHandleStatementString);
selectChatHandleStatement.setLong(1, chatResultSet.getLong(COLUMN_CHAT_ROWID));
boolean isResultSet = selectChatHandleStatement.execute();
while(true) {
if(isResultSet) {
ResultSet resultSet = selectChatHandleStatement.getResultSet();
while(resultSet.next()) {
long resultInt = resultSet.getLong(COLUMN_CHAT_HANDLE_HANDLE_ID);
handles.add(getHandleByRow(resultInt));
}
resultSet.close();
} else {
if(selectChatHandleStatement.getUpdateCount() == -1) {
break;
}
}
isResultSet = selectChatHandleStatement.getMoreResults();
}
ChatBase chat = buildChat(chatResultSet, handles);
chatResultSet.close();
selectChatStatement.close();
selectChatHandleStatement.close();
return chat;
}
/**
* Applies any database updates by comparing the current version to the
* stored version. Does nothing if tables have not been created.
*/
private static void updateDatabase() throws SQLException {
try (Statement stmt = connection.createStatement()) {
int version = 0;
// if 'info' table does not exist, assume version 0 and apply all updates
String sql = "SELECT name FROM sqlite_master WHERE type = 'table' AND name = 'info'";
ResultSet rs = stmt.executeQuery(sql);
boolean infoExists = rs.isBeforeFirst();
rs.close();
if (!infoExists) {
// if 'beatmaps' table also does not exist, databases not yet created
sql = "SELECT name FROM sqlite_master WHERE type = 'table' AND name = 'beatmaps'";
ResultSet beatmapsRS = stmt.executeQuery(sql);
boolean beatmapsExists = beatmapsRS.isBeforeFirst();
beatmapsRS.close();
if (!beatmapsExists)
return;
} else {
// try to retrieve stored version
sql = "SELECT value FROM info WHERE key = 'version'";
ResultSet versionRS = stmt.executeQuery(sql);
String versionString = (versionRS.next()) ? versionRS.getString(1) : "0";
versionRS.close();
try {
version = Integer.parseInt(versionString);
} catch (NumberFormatException e) {}
}
// database versions match
if (version >= DATABASE_VERSION)
return;
// apply updates
for (String query : getUpdateQueries(version))
stmt.executeUpdate(query);
// update version
if (infoExists) {
PreparedStatement ps = connection.prepareStatement("REPLACE INTO info (key, value) VALUES ('version', ?)");
ps.setString(1, Integer.toString(DATABASE_VERSION));
ps.executeUpdate();
ps.close();
}
}
}