[英]MySql database connection issues in play framework (driver not found)
因此,我尝试使用股票Play! 2.2配置MySql数据库连接。 不幸的是,与MySql一起使用股票数据库(h2)时,那里的指南没有多大帮助。 因此,我编写了一个单独的模型来处理MySql连接。 它间歇性地工作,我试图弄清为什么它一直都不工作。
这是“连接”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());
}
我所有的凭据都是正确的(显然这里已更改)接下来,在我的lib文件夹中,
mysql-connector-java-5.1.21-bin.jar
到位。
接下来,在我的Build.scala中,在appDependencies下有以下内容:
public boolean isConnected() {
return conn != null;
}
当我尝试验证连接时,请使用:
SQLException: Before start of result set
连接失败(间歇性地),然后给我:
SQLException: No Suitable driver found for mysql ...
有时:
String qs = String.format("SELECT * FROM community_hub.alert_journal LIMIT("+ from +","+ to +")");
这是我的查询执行方式:
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?
谢谢!
mysql错误告诉你什么吗?
第一个错误“ SQLException:结果集开始之前”看起来不完整。 错误日志中可能包含完整的消息,或者您可以
第二个“ SQLException:找不到适合mysql的驱动程序”明确指示类路径问题。
通常,建议将连接池(例如c3p0或BoneCP)建议使用验证查询来确定连接是否有效(对于mysql来说,类似于“ select 1”)。 这可能有助于确保连接正常并且不依赖驱动程序?
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