java c3p0 mysql_MySQL，c3p0和Apache Felix集成
我将MySQL集成到Apache Felix中 . 首先，我使用bndtools生成MySQL bundle和c3p0 bundle . 然后我将它们全部添加到我的Apache Felix环境中 . 我为连接池创建了一个类，如下所示：
public final class C3P0Manager {
private static C3P0Manager instance;
private DataSource pooled;
private C3P0Manager() {
// Of course, it is better to put all properties into a configuration file.
// I just list them here for easy reading.
ComboPooledDataSource cpds = new ComboPooledDataSource();
cpds.setDriverClass("com.mysql.jdbc.Driver"));
cpds.setJdbcUrl("jdbc:mysql://localhost/my-database?autoReconnect=true&characterSetResults=UTF-8&characterEncoding=UTF-8&useUnicode=yes");
cpds.setUser("user");
cpds.setPassword("password");
cpds.setInitialPoolSize(3);
cpds.setMaxPoolSize(15);
cpds.setMaxIdleTime(1800);
cpds.setAutoCommitOnClose(true);
pooled(cpds);
}
public static C3P0Manager instance() throws Exception {
if (instance == null) {
instance = new C3P0Manager();
}
return instance;
}
public DataSource getPooled() throws SQLException {
return pooled;
}
}
如果我运行JUnit测试，它工作正常 . 但是在我的Apache Felix捆绑包上运行异常消息时失败了 . 在Activator类中的用法：
Class.forName("com.mysql.jdbc.Driver");
DataSource pooled = C3P0Manager.instance().getPooled();
Connection con = pooled.getConnection();
PreparedStatement stmt = null;
ResultSet rs = null;
int total;
try {
stmt = con.prepareStatement("SELECT count(*) FROM users", Statement.NO_GENERATED_KEYS);
rs = stmt.executeQuery();
if (rs.next()) {
total = rs.getInt(1);
}
} catch (Exception e) {
e.printStackTrace();
} finally {
try {
rs.close();
stmt.close();
} catch (Exception ex) {
ex.printStackTrace();
}
}
System.out.println("total = " + total);
错误消息：
java.sql.SQLException: Connections could not be acquired from the underlying database!
at com.mchange.v2.sql.SqlUtils.toSQLException(SqlUtils.java:106)
at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool.checkoutPooledConnection(C3P0PooledConnectionPool.java:529)
at com.mchange.v2.c3p0.impl.AbstractPoolBackedDataSource.getConnection(AbstractPoolBackedDataSource.java:128)
...
Caused by: com.mchange.v2.resourcepool.CannotAcquireResourceException: A ResourcePool could not acquire a resource from its primary factory or source.
at com.mchange.v2.resourcepool.BasicResourcePool.awaitAvailable(BasicResourcePool.java:1319)
at com.mchange.v2.resourcepool.BasicResourcePool.prelimCheckoutResource(BasicResourcePool.java:557)
at com.mchange.v2.resourcepool.BasicResourcePool.checkoutResource(BasicResourcePool.java:477)
at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool.checkoutPooledConnection(C3P0PooledConnectionPool.java:525)
...
如果我只使用(没有c3p0)，MySQL可以工作：
Class.forName("com.mysql.jdbc.Driver");
Connection con = DriverManager.getConnection("jdbc:mysql://localhost/my-database?autoReconnect=true&characterSetResults=UTF-8&characterEncoding=UTF-8&useUnicode=yes","user","password");
Statement statement = connect.createStatement();
ResultSet resultSet = statement.executeQuery("SELECT count(*) FROM users");
所以我认为问题是由于c3p0 . 请帮我 . 谢谢 .