求助：Connections could not be acquired from the underlying database!


java web连接Sql Server数据库出错
我用的是sa用户登录，设置了Windows和Sql Server身份验证模式，端口没有错
一直报这个错误：
java.lang.RuntimeException: java.sql.SQLException: Connections could not be acquired from the underlying database!
at dao.impl.CategoryDaoImpl.getAll(CategoryDaoImpl.java:59)
at service.impl.BusinessServiceImpl.getAllCategory(BusinessServiceImpl.java:46)
at web.manager.CategoryServlet.listAll(CategoryServlet.java:64)
at web.manager.CategoryServlet.doGet(CategoryServlet.java:30)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:731)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:844)
at weblogic.servlet.internal.StubSecurityHelper$ServletServiceAction.run(StubSecurityHelper.java:280)
at weblogic.servlet.internal.StubSecurityHelper$ServletServiceAction.run(StubSecurityHelper.java:254)
at weblogic.servlet.internal.StubSecurityHelper.invokeServlet(StubSecurityHelper.java:136)
at weblogic.servlet.internal.ServletStubImpl.execute(ServletStubImpl.java:346)
at weblogic.servlet.internal.TailFilter.doFilter(TailFilter.java:25)
at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:79)
at filter.HtmlFilter.doFilter(HtmlFilter.java:23)
at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:79)
at filter.CharactorEncodingFilter.doFilter(CharactorEncodingFilter.java:28)
at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:79)
at weblogic.servlet.internal.WebAppServletContext$ServletInvocationAction.wrapRun(WebAppServletContext.java:3436)
at weblogic.servlet.internal.WebAppServletContext$ServletInvocationAction.run(WebAppServletContext.java:3402)
at weblogic.security.acl.internal.AuthenticatedSubject.doAs(AuthenticatedSubject.java:321)
at weblogic.security.service.SecurityManager.runAs(SecurityManager.java:120)
at weblogic.servlet.provider.WlsSubjectHandle.run(WlsSubjectHandle.java:57)
at weblogic.servlet.internal.WebAppServletContext.doSecuredExecute(WebAppServletContext.java:2285)
at weblogic.servlet.internal.WebAppServletContext.securedExecute(WebAppServletContext.java:2201)
at weblogic.servlet.internal.WebAppServletContext.execute(WebAppServletContext.java:2179)
at weblogic.servlet.internal.ServletRequestImpl.run(ServletRequestImpl.java:1572)
at weblogic.servlet.provider.ContainerSupportProviderImpl$WlsRequestExecutor.run(ContainerSupportProviderImpl.java:255)
at weblogic.work.ExecuteThread.execute(ExecuteThread.java:311)
at weblogic.work.ExecuteThread.run(ExecuteThread.java:263)
Caused by: java.sql.SQLException: Connections could not be acquired from the underlying database!
at com.mchange.v2.sql.SqlUtils.toSQLException(SqlUtils.java:118)
at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool.checkoutPooledConnection(C3P0PooledConnectionPool.java:692)
at com.mchange.v2.c3p0.impl.AbstractPoolBackedDataSource.getConnection(AbstractPoolBackedDataSource.java:140)
at org.apache.commons.dbutils.AbstractQueryRunner.prepareConnection(AbstractQueryRunner.java:204)
at org.apache.commons.dbutils.QueryRunner.query(QueryRunner.java:305)
at dao.impl.CategoryDaoImpl.getAll(CategoryDaoImpl.java:56)
... 27 more
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:1469)
at com.mchange.v2.resourcepool.BasicResourcePool.prelimCheckoutResource(BasicResourcePool.java:644)
at com.mchange.v2.resourcepool.BasicResourcePool.checkoutResource(BasicResourcePool.java:554)
at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool.checkoutAndMarkConnectionInUse(C3P0PooledConnectionPool.java:758)
at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool.checkoutPooledConnection(C3P0PooledConnectionPool.java:685)
... 31 mor
这是我的XML代码：
<default-config>
<property name="driverClass">net.sourceforge.jtds.jdbc.Driver</property>
<property name="jdbcUrl">jdbc:jtds:sqlserver://localhost:1433;DatabaseName=bookstore</property>
<property name="user">sa</property>
<property name="password">123456</property>

<property name="acquireIncrement">5</property>
<property name="initialPoolSize">10</property>
<property name="minPoolSize">5</property>
<property name="maxPoolSize">20</property> <!-- intergalactoApp adopts a different approach to configuring statement 
caching -->
<property name="maxStatements">0</property>
<property name="maxStatementsPerConnection">5</property> <!-- he's important, but there's only one of him -->
</default-config>

<named-config name="mysql">
<property name="driverClass">net.sourceforge.jtds.jdbc.Driver</property>
<property name="jdbcUrl">jdbc:jtds:sqlserver://localhost:1433;DatabaseName=bookstore</property>
<property name="user">sa</property>
<property name="password">123456</property>

<property name="acquireIncrement">5</property>
<property name="initialPoolSize">10</property>
<property name="minPoolSize">5</property>
<property name="maxPoolSize">20</property> <!-- intergalactoApp adopts a different approach to configuring statement 
caching -->
<property name="maxStatements">0</property>
<property name="maxStatementsPerConnection">5</property> <!-- he's important, but there's only one of him -->
</named-config>
</c3p0-config>