我正在使用eclipse创建一个动态Web项目，我想使用tomcat 7.0.50和一个使用连接池的postgresql数据库。 我已经在apache-tomcat-7.0.50 / lib中复制了postgresql-9.2-1003.jdbc4.jar文件。 那是apache-tomcat-7.0.50 / conf中的context.xml文件：
<?xml version='1.0' encoding='utf-8'?>
<Context>
<WatchedResource>WEB-INF/web.xml</WatchedResource>
<Resource
type="javax.sql.DataSource"
name="jdbc/Fantacalcio"
factory="org.apache.tomcat.jdbc.pool.DataSourceFactory"
driverClassName="org.postgresql.Driver"
url="jdbc:postgresql://localhost:5432/Fantacalcio"
username="postgres"
password="mypassword"
initialSize="0"
maxActive="80"
maxIdle = "30"
minIdle="20"
timeBetweenEvictionRunsMillis="30000"
minEvictableIdleTimeMillis="60000"
testOnBorrow="true"
validationQuery="SELECT 1"
validationInterval="30000"
removeAbandoned="true"
removeAbandonedTimeout="60"
logAbandoned="true"
abandonWhenPercentageFull="60"
jdbcInterceptors="org.apache.tomcat.jdbc.pool.interceptor.ResetAbandonedTimer"/>
</Context>
这是项目的WEB-INF文件夹中的web.xml文件：
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" id="WebApp_ID" version="2.5">
<display-name>Fantacalcio</display-name>
<welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
<servlet>
<description></description>
<display-name>AbstractDatabaseServlet</display-name>
<servlet-name>AbstractDatabaseServlet</servlet-name>
<servlet-class>servlet.AbstractDatabaseServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>AbstractDatabaseServlet</servlet-name>
<url-pattern>/AbstractDatabaseServlet</url-pattern>
</servlet-mapping>
<servlet>
<description></description>
<display-name>ShowIndexServlet</display-name>
<servlet-name>ShowIndexServlet</servlet-name>
<servlet-class>servlet.ShowIndexServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>ShowIndexServlet</servlet-name>
<url-pattern>/ShowIndexServlet</url-pattern>
</servlet-mapping>
<resource-ref>
<description>Connection Pool</description>
<res-ref-name>jdbc/Fantacalcio</res-ref-name>
<res-type>javax.sql.Datasource</res-type>
<res-auth>Container</res-auth>
</resource-ref>
</web-app>
这是负责连接池的java类：
public abstract class AbstractDatabaseServlet extends HttpServlet {
protected static final DataSource DS;
static {
InitialContext cxt;
DataSource ds = null;
try {
cxt = new InitialContext();
ds = (DataSource) cxt.lookup("java:/comp/env/jdbc/Fantacalcio");
} catch (NamingException e) {
ds = null;
e.printStackTrace();
} finally {DS = ds;}
}
}
这是想要建立连接的servlet：
import java.sql.Connection;
import java.sql.SQLException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class ShowIndexServlet extends AbstractDatabaseServlet {
private static final long serialVersionUID = 1L;
protected void doGet(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException{
Connection con = null;
try {
con = DS.getConnection();
// use of connection con to interact with the database...
} catch (SQLException ex) {
} finally {
if (con != null) {
try {
con.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
}
编辑：离开namingException后的完整堆栈跟踪
15-feb-2014 18.53.27 org.apache.catalina.core.AprLifecycleListener init
INFO: The APR based Apache Tomcat Native library which allows optimal performance in production environments was not found on the java.library.path: .:/Library/Java/Extensions:/System/Library/Java/Extensions:/usr/lib/java
15-feb-2014 18.53.27 org.apache.tomcat.util.digester.SetPropertiesRule begin
AVVERTENZA: [SetPropertiesRule]{Server/Service/Engine/Host/Context} Setting property 'source' to 'org.eclipse.jst.jee.server:Fantacalcio' did not find a matching property.
15-feb-2014 18.53.27 org.apache.coyote.AbstractProtocol init
INFO: Initializing ProtocolHandler ["http-bio-8080"]
15-feb-2014 18.53.27 org.apache.coyote.AbstractProtocol init
INFO: Initializing ProtocolHandler ["ajp-bio-8009"]
15-feb-2014 18.53.27 org.apache.catalina.startup.Catalina load
INFO: Initialization processed in 610 ms
15-feb-2014 18.53.27 org.apache.catalina.core.StandardService startInternal
INFO: Starting service Catalina
15-feb-2014 18.53.27 org.apache.catalina.core.StandardEngine startInternal
INFO: Starting Servlet Engine: Apache Tomcat/7.0.50
15-feb-2014 18.53.28 org.apache.tomcat.websocket.server.WsSci onStartup
INFO: JSR 356 WebSocket (Java WebSocket 1.0) support is not available when running on Java 6. To suppress this message, run Tomcat on Java 7, remove the WebSocket JARs from $CATALINA_HOME/lib or add the WebSocketJARs to the tomcat.util.scan.DefaultJarScanner.jarsToSkip property in $CATALINA_BASE/conf/catalina.properties. Note that the deprecated Tomcat 7 WebSocket API will be available.
15-feb-2014 18.53.28 org.apache.coyote.AbstractProtocol start
INFO: Starting ProtocolHandler ["http-bio-8080"]
15-feb-2014 18.53.28 org.apache.coyote.AbstractProtocol start
INFO: Starting ProtocolHandler ["ajp-bio-8009"]
15-feb-2014 18.53.28 org.apache.catalina.startup.Catalina start
INFO: Server startup in 1225 msjavax.naming.NamingException: Cannot create resource instance
at org.apache.naming.factory.ResourceFactory.getObjectInstance(ResourceFactory.java:146)
at javax.naming.spi.NamingManager.getObjectInstance(NamingManager.java:304)
at org.apache.naming.NamingContext.lookup(NamingContext.java:843)
at org.apache.naming.NamingContext.lookup(NamingContext.java:154)
at org.apache.naming.NamingContext.lookup(NamingContext.java:831)
at org.apache.naming.NamingContext.lookup(NamingContext.java:154)
at org.apache.naming.NamingContext.lookup(NamingContext.java:831)
at org.apache.naming.NamingContext.lookup(NamingContext.java:154)
at org.apache.naming.NamingContext.lookup(NamingContext.java:831)
at org.apache.naming.NamingContext.lookup(NamingContext.java:168)
at org.apache.naming.SelectorContext.lookup(SelectorContext.java:158)
at javax.naming.InitialContext.lookup(InitialContext.java:392)
at servlet.AbstractDatabaseServlet.<clinit>(AbstractDatabaseServlet.java:28)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
at java.lang.Class.newInstance0(Class.java:357)
at java.lang.Class.newInstance(Class.java:310)
at org.apache.catalina.core.DefaultInstanceManager.newInstance(DefaultInstanceManager.java:143)
at org.apache.catalina.core.StandardWrapper.loadServlet(StandardWrapper.java:1144)
at org.apache.catalina.core.StandardWrapper.allocate(StandardWrapper.java:865)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:136)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:100)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:953)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:409)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1044)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:607)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:313)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:895)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:918)
at java.lang.Thread.run(Thread.java:695)
15-feb-2014 18.54.05 org.apache.catalina.core.StandardWrapperValve invoke
GRAVE: Servlet.service() for servlet [ShowIndexServlet] in context with path [/Fantacalcio] threw exception
java.lang.NullPointerException
at servlet.ShowIndexServlet.doGet(ShowIndexServlet.java:38)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:621)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:222)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:100)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:953)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:409)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1044)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:607)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:313)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:895)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:918)
at java.lang.Thread.run(Thread.java:695)
P.S。我是意大利人，抱歉我的英语不完美！