oracle 连接问题

Question

报的错：

[ERROR]org.logicalcobwebs.proxool.lantoudb:Prototype
java.sql.SQLException: Listener refused the connection with the following error:
ORA-12505, TNS:listener does not currently know of SID given in connect descriptor
The Connection descriptor used by the client was:
localhost:1521:orcl

at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:112)
at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:261)
at oracle.jdbc.driver.T4CConnection.logon(T4CConnection.java:387)
at oracle.jdbc.driver.PhysicalConnection.<init>(PhysicalConnection.java:414)
at oracle.jdbc.driver.T4CConnection.<init>(T4CConnection.java:165)
at oracle.jdbc.driver.T4CDriverExtension.getConnection(T4CDriverExtension.java:35)
at oracle.jdbc.driver.OracleDriver.connect(OracleDriver.java:801)
at java.sql.DriverManager.getConnection(DriverManager.java:582)
at java.sql.DriverManager.getConnection(DriverManager.java:154)
at org.logicalcobwebs.proxool.DefaultConnectionBuilder.buildConnection(DefaultConnectionBuilder.java:39)
at org.logicalcobwebs.proxool.Prototyper.buildConnection(Prototyper.java:159)
at org.logicalcobwebs.proxool.Prototyper.sweep(Prototyper.java:102)
at org.logicalcobwebs.proxool.PrototyperThread.run(PrototyperThread.java:44)

连接配置

 <driver-url>jdbc:oracle:thin:@127.0.0.1:1521:DB</driver-url>
<driver-class>oracle.jdbc.driver.OracleDriver</driver-class>
<driver-properties>
  <property name="user" value="lantou"/>
  <property name="password" value="lantou"/>
</driver-properties>

我这怎么就出了这个问题呢？？？？

用plsql 连db 是正常的连上的。。。。

可以肯定的是我之前的项目都这么连的都 没有问题

Answer 1

必须确保你的数据库最大连接数，这是并发问题，最好写个连接池，应该就可以解决了。