我是J2EE技术的新手,并尝试使用JSF,Spring和Hibernate创建基本的Web应用程序。我也使用PostgreSQL。在服务器启动期间,我遇到了这个异常:
WARNING: com.mchange.v2.resourcepool.BasicResourcePool$ScatteredAcquireTask@173b4cf -- Acquisition Attempt Failed!!! Clearing pending acquires. While trying to acquire a needed new resource, we failed to succeed more than the maximum number of allowed acquisition attempts (30). Last acquisition attempt exception:
java.lang.NullPointerException
at sun.jdbc.odbc.JdbcOdbcDriver.getProtocol(Unknown Source)
at sun.jdbc.odbc.JdbcOdbcDriver.knownURL(Unknown Source)
at sun.jdbc.odbc.JdbcOdbcDriver.acceptsURL(Unknown Source)
at java.sql.DriverManager.getDriver(Unknown Source)
at com.mchange.v2.c3p0.DriverManagerDataSource.driver(DriverManagerDataSource.java:240)
at com.mchange.v2.c3p0.DriverManagerDataSource.getConnection(DriverManagerDataSource.java:131)
at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:156)
at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:145)
at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool$1PooledConnectionResourcePoolManager.acquireResource(C3P0PooledConnectionPool.java:200)
at com.mchange.v2.resourcepool.BasicResourcePool.doAcquire(BasicResourcePool.java:1086)
at com.mchange.v2.resourcepool.BasicResourcePool.doAcquireAndDecrementPendingAcquiresWithinLockOnSuccess(BasicResourcePool.java:1073)
at com.mchange.v2.resourcepool.BasicResourcePool.access$800(BasicResourcePool.java:44)
at com.mchange.v2.resourcepool.BasicResourcePool$ScatteredAcquireTask.run(BasicResourcePool.java:1810)
at com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:648)
Dec 09, 2015 11:13:21 AM com.mchange.v2.resourcepool.BasicResourcePool$ScatteredAcquireTask run
WARNING: com.mchange.v2.resourcepool.BasicResourcePool$ScatteredAcquireTask@173b4cf -- Acquisition Attempt Failed!!! Clearing pending acquires. While trying to acquire a needed new resource, we failed to succeed more than the maximum number of allowed acquisition attempts (30). Last acquisition attempt exception:
java.lang.NullPointerException
at sun.jdbc.odbc.JdbcOdbcDriver.getProtocol(Unknown Source)
at sun.jdbc.odbc.JdbcOdbcDriver.knownURL(Unknown Source)
at sun.jdbc.odbc.JdbcOdbcDriver.acceptsURL(Unknown Source)
at java.sql.DriverManager.getDriver(Unknown Source)
at com.mchange.v2.c3p0.DriverManagerDataSource.driver(DriverManagerDataSource.java:240)
at com.mchange.v2.c3p0.DriverManagerDataSource.getConnection(DriverManagerDataSource.java:131)
at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:156)
at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:145)
at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool$1PooledConnectionResourcePoolManager.acquireResource(C3P0PooledConnectionPool.java:200)
at com.mchange.v2.resourcepool.BasicResourcePool.doAcquire(BasicResourcePool.java:1086)
at com.mchange.v2.resourcepool.BasicResourcePool.doAcquireAndDecrementPendingAcquiresWithinLockOnSuccess(BasicResourcePool.java:1073)
at com.mchange.v2.resourcepool.BasicResourcePool.access$800(BasicResourcePool.java:44)
at com.mchange.v2.resourcepool.BasicResourcePool$ScatteredAcquireTask.run(BasicResourcePool.java:1810)
at com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:648)
Dec 09, 2015 11:13:21 AM com.mchange.v2.resourcepool.BasicResourcePool$ScatteredAcquireTask run
WARNING: com.mchange.v2.resourcepool.BasicResourcePool$ScatteredAcquireTask@5e53d -- Acquisition Attempt Failed!!! Clearing pending acquires. While trying to acquire a needed new resource, we failed to succeed more than the maximum number of allowed acquisition attempts (30). Last acquisition attempt exception:
java.lang.NullPointerException
at sun.jdbc.odbc.JdbcOdbcDriver.getProtocol(Unknown Source)
at sun.jdbc.odbc.JdbcOdbcDriver.knownURL(Unknown Source)
at sun.jdbc.odbc.JdbcOdbcDriver.acceptsURL(Unknown Source)
at java.sql.DriverManager.getDriver(Unknown Source)
at com.mchange.v2.c3p0.DriverManagerDataSource.driver(DriverManagerDataSource.java:240)
at com.mchange.v2.c3p0.DriverManagerDataSource.getConnection(DriverManagerDataSource.java:131)
at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:156)
at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:145)
at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool$1PooledConnectionResourcePoolManager.acquireResource(C3P0PooledConnectionPool.java:200)
at com.mchange.v2.resourcepool.BasicResourcePool.doAcquire(BasicResourcePool.java:1086)
at com.mchange.v2.resourcepool.BasicResourcePool.doAcquireAndDecrementPendingAcquiresWithinLockOnSuccess(BasicResourcePool.java:1073)
at com.mchange.v2.resourcepool.BasicResourcePool.access$800(BasicResourcePool.java:44)
at com.mchange.v2.resourcepool.BasicResourcePool$ScatteredAcquireTask.run(BasicResourcePool.java:1810)
at com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:648)
我在下面提供了我的配置文件和相关课程:
应用context.xml中:
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:tx="http://www.springframework.org/schema/tx"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/tx
http://www.springframework.org/schema/tx/spring-tx.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context.xsd">
<bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
<property name="driverClassName" value="org.postgresql.Driver" />
<property name="url" value="jdbc:postgresql://localhost:5432/SomeDB" />
<property name="username" value="postgres" />
<property name="password" value="1234" />
</bean>
<bean id="sessionFactory" class="org.springframework.orm.hibernate5.LocalSessionFactoryBean">
<property name="dataSource" ref="dataSource" />
<property name="packagesToScan" value="tr.mypackage" />
<property name="hibernateProperties">
<props>
<prop key="hibernate.dialect">org.hibernate.dialect.PostgreSQLDialect</prop>
<prop key="hibernate.connection.provider_class">org.hibernate.connection.C3P0ConnectionProvider</prop>
<prop key="hibernate.c3p0.acquire_increment">1</prop>
</props>
</property>
</bean>
<bean id="transactionManager" class="org.springframework.orm.hibernate5.HibernateTransactionManager">
<property name="sessionFactory" ref="sessionFactory" />
</bean>
<tx:annotation-driven transaction-manager="transactionManager" />
<context:annotation-config />
<context:component-scan base-package="tr.mypackage" />
</beans>
的web.xml:
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns="http://xmlns.jcp.org/xml/ns/javaee"
xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"
id="WebApp_ID" version="3.1">
<display-name>Some Display Name</display-name>
<!-- JSF -->
<servlet>
<servlet-name>Faces Servlet</servlet-name>
<servlet-class>javax.faces.webapp.FacesServlet</servlet-class>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>Faces Servlet</servlet-name>
<url-pattern>*.xhtml</url-pattern>
</servlet-mapping>
<!-- SPRING -->
<context-param>
<param-name>contextConfigLocation</param-name>
<param-value>/WEB-INF/application-context.xml</param-value>
</context-param>
<listener>
<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>
<listener>
<listener-class>org.springframework.web.context.request.RequestContextListener</listener-class>
</listener>
<!-- OTHER -->
<welcome-file-list>
<welcome-file>index.xhtml</welcome-file>
</welcome-file-list>
</web-app>
Person.java
package tr.mypackage;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.Table;
import com.sun.istack.internal.NotNull;
@Entity
@Table(name="person_t")
public class Person {
@Id
@NotNull
@GeneratedValue
private int id;
@Column
private String firstName;
public Person(){
}
public Person(int id, String firstName) {
super();
this.id = id;
this.firstName = firstName;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getFirstName() {
return firstName;
}
public void setFirstName(String firstName) {
this.firstName = firstName;
}
}
那么,对于我的错误在哪里有什么想法吗?
答案 0 :(得分:2)
问题的直接原因是您实际上没有向使用这些设置进行休眠构建的c3p0数据源提供任何连接信息。
<prop key="hibernate.connection.provider_class">org.hibernate.connection.C3P0ConnectionProvider</prop>
<prop key="hibernate.c3p0.acquire_increment">1</prop>
请参阅Spring docs:您在Spring中配置的DataSource与hibernate的SessionFactory可能在内部构建的不同。您已经提供了足够的配置来使hibernate构建DataSource,但是您没有提供正确配置它所需的hibernate.connection.*
参数。
最简单的方法是摆脱在Spring中配置的DataSource,并在hibernate中完成c3p0 DataSource的配置。有关当前缺少的各种连接参数,请参阅hibernate docs。您还可以将c3p0 configuration parameters设置为hibernate.c3p0.fooBarBlah
(其中fooBarBlah
显然应替换为实际参数名称)。 [请注意,对于max_size
和maxPoolSize
等具有休眠名称和c3p0名称的参数,hibernate name will override c3p0-name settings。]
或者,您可以摆脱上面的两个hibernate属性,并提供在Spring中配置的自己的DataSource。如果您想要连接池,则可能不是您的DataSource是org.springframework.jdbc.datasource.DriverManagerDataSource
。您可以直接在Spring中配置com.mchange.v2.c3p0.ComboPooledDataSource
,就像配置未池化的DriverManagerDataSource一样。有关示例,请参阅this article中的“让Spring管理池”一节。
答案 1 :(得分:0)
如果您使用的是eclipse,并且遇到此错误,那么您只需要更改mysql连接器(在我的情况下就可以正常使用)。
较新的版本正在使用caching_sha2_password
。