Question

我正在尝试使用jdbcTemplate连接到Java中的数据库，我得到以下错误。我用谷歌搜索了很长时间，我找到的所有解决方案都没有解决我的问题。我尝试了几个不同的数据库（SQLServer和MySQL），但都没有工作。

SEVERE: Servlet.service() for servlet [Faces Servlet] in context with path [/promotion-handler-admin] threw exception [Could not open JDBC Connection for transaction; nested exception is java.sql.SQLException: Connections could not be acquired from the underlying database!] with root cause
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)
    at com.mchange.v2.c3p0.impl.AbstractPoolBackedDataSource.getConnection(AbstractPoolBackedDataSource.java:128)
    at org.springframework.jdbc.datasource.DataSourceTransactionManager.doBegin(DataSourceTransactionManager.java:202)
    at org.springframework.transaction.support.AbstractPlatformTransactionManager.getTransaction(AbstractPlatformTransactionManager.java:371)
    at org.springframework.transaction.interceptor.TransactionAspectSupport.createTransactionIfNecessary(TransactionAspectSupport.java:335)
    at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:105)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
    at org.springframework.aop.framework.Cglib2AopProxy$DynamicAdvisedInterceptor.intercept(Cglib2AopProxy.java:622)
    ...

这是我的属性文件：

app.driverClassName=net.sourceforge.jtds.jdbc.Driver
app.url=jdbc:sqlserver://myUrl:port;databaseName=my_database
app.username=myUsername
app.password=myPassword

web应用/ WEB-INF /的applicationContext-database.xml：

<beans:bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource"
    destroy-method="close">
    <beans:property name="driverClass" value="${app.driverClassName}" />
    <beans:property name="jdbcUrl"
        value="${app.url}" />
    <beans:property name="user" value="${app.username}" />
    <beans:property name="password" value="${app.password}" />
    <beans:property name="acquireIncrement" value="5" />
    <beans:property name="idleConnectionTestPeriod" value="600" />
    <beans:property name="maxPoolSize" value="10" />
    <beans:property name="maxStatements" value="5" />
    <beans:property name="minPoolSize" value="3" />
    <beans:property name="preferredTestQuery" value="select 1 from DUAL" />
</beans:bean>

<!-- TRANSACTION_MANAGERS -->
<!-- See http://static.springsource.org/spring/docs/3.0.x/spring-framework-reference/html/transaction.html -->

<!-- Default -->
<beans:bean id="transactionManager"
    class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
    <beans:property name="dataSource" ref="dataSource" />
</beans:bean>

DAO课程：

@Repository
public class CampaignDAO {
    private JdbcTemplate jdbcTemplate;

    @Resource(name = "dataSource")
    public void setDataSource(DataSource dataSource) {
        this.jdbcTemplate = new JdbcTemplate(dataSource);
    }

public List<Campaign> getCampaignList() {
    Long start = System.currentTimeMillis();

    List<Campaign> queryList;

    try {
        queryList = jdbcTemplate.query("SELECT * FROM campaign", new RowMapper<Campaign>() {
            public Campaign mapRow(ResultSet rs, int line) throws SQLException {
                Campaign campaign = new Campaign();
                campaign.setId(rs.getLong("id"));
                campaign.setExtraInfo(rs.getString("extra_info"));
                campaign.setBeginTime(rs.getDate("begin_time"));
                campaign.setEndTime(rs.getDate("end_time"));

                return campaign;

            }
        });
    } finally {
         ...
    }
    return queryList;
}

Answer 1

对于将来发现此问题的任何人。我做错了是因为我使用的是jtds驱动程序，我忘了在网址中添加它。所以在我的属性文件中我应该做的是：

app.url=jdbc:jtds:sqlserver://myUrl:port;databaseName=my_database

Answer 2

对于将来发现此问题的任何人。

这也可能是由于缺少数据库驱动程序引起的。

在我的情况下，我使用maven-shade-plugin并设置了minimizeJar选项。这当然是丢弃了jtds驱动程序，因为它没有直接引用到任何地方。

这可以修复如下：

  <plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-shade-plugin</artifactId>
    <version>1.6</version>
    <executions>
      <execution>
        <phase>package</phase>
        <goals>
          <goal>shade</goal>
        </goals>
        <configuration>
          <minimizeJar>true</minimizeJar>
          <filters>
            <filter>
              <!-- Make sure jtds is included. -->
               <artifact>net.sourceforge.jtds:jtds</artifact>
               <includes>
                   <include>**</include>
               </includes>
            </filter>
            <filter>
              <artifact>*:*</artifact>
              <excludes>
                <exclude>META-INF/*.SF</exclude>
                <exclude>META-INF/*.DSA</exclude>
                <exclude>META-INF/*.RSA</exclude>
                <exclude>META-INF/*.sf</exclude>
                <exclude>META-INF/*.dsa</exclude>
                <exclude>META-INF/*.rsa</exclude>
              </excludes>
            </filter>
          </filters>
        </configuration>
      </execution>
    </executions>
  </plugin>

Answer 3

如果像我一样使用Tomcat的Maven插件运行您的应用程序，也可以显示此消息：

 new Handler(getContext().get().getMainLooper()).post(() -> {
     if (CommonHelper.isNOrAbove()) {
        connectedGatt = connectedBLEDevice.connectGatt(context.get(), true, gattCallback, BluetoothDevice.TRANSPORT_AUTO);
         Timber.tag("HED-BT").d("Connecting BLE after N");
     } else {   
        try {
            Method connectGattMethod = connectedBLEDevice.getClass().getMethod("connectGatt", Context.class, boolean.class, BluetoothGattCallback.class, int.class);
             connectedGatt = (BluetoothGatt) connectGattMethod.invoke(connectedBLEDevice, context.get(), false, gattCallback, BluetoothDevice.TRANSPORT_AUTO);
             Timber.tag("HED-BT").d("Connecting BLE before N");
         } catch (Exception e) {
             failedConnectingBLE();
         }
     }
 });

你的Maven依赖项中有一个mvn clean install tomcat7:run范围元素：

provided

<dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <version>5.1.36</version> <scope>provided</scope> </dependency>范围将阻止连接器成为provided存档的一部分，并且Tomcat插件将找不到用于建立数据库连接的连接器。

只需从依赖项中删除war范围即可解决问题。

Answer 4

在我的情况下，问题与MySQL和mysql-connector-java之间的版本错误有关。经过几天的头痛之后，我在一个单独的干净项目中取出了ComboPooledDataSource模块，并尝试将其连接到MySQL。但是，我得到了stacktrace（很遗憾，我忘记了确切的内容），据我了解，问题与版本有关。

Answer 5

我在mchange-commons-java 0.2.6.3的c3p0 0.9.5-pre6上遇到了这个问题。降级到c3p0 0.9.5-pre5和mchange-commons-java 0.2.6.2之后，问题就消失了。

ResourcePool无法从其主工厂或源获取资源

5 个答案: