[英]MySql database connection issues in play framework (driver not found)
因此,我嘗試使用股票Play! 2.2配置MySql數據庫連接。 不幸的是,與MySql一起使用股票數據庫(h2)時,那里的指南沒有多大幫助。 因此,我編寫了一個單獨的模型來處理MySql連接。 它間歇性地工作,我試圖弄清為什么它一直都不工作。
這是“連接”功能
String sourceSchema = "db";
String databaseHost = "host";
String databaseURLSource = "jdbc:mysql://" + databaseHost + "/" + sourceSchema;
String databaseUserIDSource = "userid";
String databasePWDSource = "password";
try {
Class.forName("com.mysql.jdbc.Driver").newInstance();
conn = DriverManager.getConnection(databaseURLSource,
databaseUserIDSource, databasePWDSource);
return true;
} catch (InstantiationException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IllegalAccessException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (SQLException e) {
Logger.error("SQLException: " + e.getMessage());
}
我所有的憑據都是正確的(顯然這里已更改)接下來,在我的lib文件夾中,
mysql-connector-java-5.1.21-bin.jar
到位。
接下來,在我的Build.scala中,在appDependencies下有以下內容:
public boolean isConnected() {
return conn != null;
}
當我嘗試驗證連接時,請使用:
SQLException: Before start of result set
連接失敗(間歇性地),然后給我:
SQLException: No Suitable driver found for mysql ...
有時:
String qs = String.format("SELECT * FROM community_hub.alert_journal LIMIT("+ from +","+ to +")");
這是我的查詢執行方式:
String qscount = String.format("SELECT COUNT(*) AS count FROM community_hub.alert_journal");
try {
if (isConnected()) {
Statement stmt = conn.createStatement();
//obtain count of rows
ResultSet rs1 = stmt.executeQuery(qscount);
//returns the number of pages to draw on index
int numPages = returnPages(rs1.getInt("count"),rpp);
NumPages(numPages);
ResultSet rs = stmt.executeQuery(qs);
while (rs.next())
{
AlertEntry ae = new AlertEntry(
rs.getTimestamp("date"),
rs.getString("service_url"),
rs.getString("type"),
rs.getString("offering_id"),
rs.getString("observed_property"),
rs.getString("detail")
);
list.add(ae);
}
rs.close();
disconnect();
} else {
System.err.println("Connection was null");
}
}
catch (Exception e)
{
e.printStackTrace();
}
String qscount = String.format("SELECT COUNT(*) AS count FROM community_hub.alert_journal"); try { if (isConnected()) { Statement stmt = conn.createStatement(); //obtain count of rows ResultSet rs1 = stmt.executeQuery(qscount); //returns the number of pages to draw on index int numPages = returnPages(rs1.getInt("count"),rpp); NumPages(numPages); ResultSet rs = stmt.executeQuery(qs); while (rs.next()) { AlertEntry ae = new AlertEntry( rs.getTimestamp("date"), rs.getString("service_url"), rs.getString("type"), rs.getString("offering_id"), rs.getString("observed_property"), rs.getString("detail") ); list.add(ae); } rs.close(); disconnect(); } else { System.err.println("Connection was null"); } } catch (Exception e) { e.printStackTrace(); }
救命?
謝謝!
mysql錯誤告訴你什么嗎?
第一個錯誤“ SQLException:結果集開始之前”看起來不完整。 錯誤日志中可能包含完整的消息,或者您可以
第二個“ SQLException:找不到適合mysql的驅動程序”明確指示類路徑問題。
通常,建議將連接池(例如c3p0或BoneCP)建議使用驗證查詢來確定連接是否有效(對於mysql來說,類似於“ select 1”)。 這可能有助於確保連接正常並且不依賴驅動程序?
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