tomcat 数据库连接池

ck1987

一。复制数据库连接器.jar包 到tomcat$\common\lib下，因为在项目\WEB-INF\lib 下是没用的，它是由tomcat 管理的
二。tomcat\conf\servlet.xml，下面是个人项目源码{

<?xml version='1.0' encoding='utf-8'?>
<Server>
<Listener className="org.apache.catalina.mbeans.ServerLifecycleListener"/>
<Listener className="org.apache.catalina.mbeans.GlobalResourcesLifecycleListener"/>
<GlobalNamingResources>
<Environment name="simpleValue" type="java.lang.Integer" value="30"/>
<Resource auth="Container" description="User database that can be updated and saved" name="UserDatabase" type="org.apache.catalina.UserDatabase"/>
<ResourceParams name="UserDatabase">
<parameter>
<name>factory</name>
<value>org.apache.catalina.users.MemoryUserDatabaseFactory</value>
</parameter>
<parameter>
<name>pathname</name>
<value>conf/tomcat-users.xml</value>
</parameter>
</ResourceParams>
</GlobalNamingResources>
<Service name="Catalina">
<Connector acceptCount="100" connectionTimeout="20000" disableUploadTimeout="true" port="8080" redirectPort="8443" maxSpareThreads="75" maxThreads="150" minSpareThreads="25">
</Connector>
<Connector port="8009" protocol="AJP/1.3" protocolHandlerClassName="org.apache.jk.server.JkCoyoteHandler" redirectPort="8443">
</Connector>
<Engine defaultHost="localhost" name="Catalina">
<Host appBase="webapps" name="localhost">
<Logger className="org.apache.catalina.logger.FileLogger" prefix="localhost_log." suffix=".txt" timestamp="true"/>
<!-- Ibox_two 与项目同名-->
<Context path=" /Ibox_two" docBase="Ibox_two" debug="0" crosscontext="true" reloadable="true">
<Resource name="jdbc/testdt" auth="Container" type="javax.sql.DataSource" />
<ResourceParams name="jdbc/testdt">
<parameter>
<name>maxWait</name>
<value>5000</value>
</parameter>
<parameter>
<name>maxActive</name>
<value>4</value>
</parameter>
<parameter>
<name>password</name>
<value>1234</value>
</parameter>
<parameter>
<name>url</name>
<value>jdbc:mysql://127.0.0.1:3306/test</value>
</parameter>
<parameter>
<name>driverClassName</name>
<value>com.mysql.jdbc.Driver</value>
</parameter>
<parameter>
<name>maxIdle</name>
<value>2</value>
</parameter>
<parameter>
<name>username</name>
<value>root</value>
</parameter>
</ResourceParams>
</Context>
</Host>
<Logger className="org.apache.catalina.logger.FileLogger" prefix="catalina_log." suffix=".txt" timestamp="true"/>
<Realm className="org.apache.catalina.realm.UserDatabaseRealm"/>
</Engine>
</Service>
</Server>

}

三。项目\WEB-INF\web.xml ,下面源码，个人项目源码{

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" version="2.4" xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee   http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">
<servlet>
<servlet-name>action</servlet-name>
<servlet-class>com.servlet.ServletAction</servlet-class>
<init-param>
<param-name>config</param-name>
<param-value>/WEB-INF/struts-config.xml</param-value>
</init-param>
<init-param>
<param-name>debug</param-name>
<param-value>3</param-value>
</init-param>
<init-param>
<param-name>detail</param-name>
<param-value>3</param-value>
</init-param>
<load-on-startup>0</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>action</servlet-name>
<url-pattern>*.do</url-pattern>
</servlet-mapping>

<!-- 配置DWR的核心Servlet -->
<servlet>
<!-- 指定DWR核心Servlet的名字 -->
<servlet-name>dwr-invoker</servlet-name>
<!-- 指定DWR核心Servlet的实现类 -->
<servlet-class>uk.ltd.getahead.dwr.DWRServlet</servlet-class>
<!--  指定DWR核心Servlet处于调试状态 -->
<init-param>
<param-name>debug</param-name>
<param-value>true</param-value>
</init-param>
<!-- 设置使用反向Ajax技术 -->
<init-param>
<param-name>pollAndCometEnabled</param-name>
<param-value>true</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>
<!-- 指定核心Servlet的URL映射 -->
<servlet-mapping>
<servlet-name>dwr-invoker</servlet-name>
<!-- 指定核心Servlet映射的URL -->
<url-pattern>/dwr/*</url-pattern>
</servlet-mapping>
<welcome-file-list>
<welcome-file>index.html</welcome-file>
<welcome-file>index.jsp</welcome-file>
<welcome-file>index.do</welcome-file>
</welcome-file-list>
<resource-ref>
<description>MySQL DB Connection Pool</description>
<res-ref-name>jdbc/testdt</res-ref-name>
<res-type>javax.sql.DataSource</res-type>
<res-auth>Container</res-auth>
<res-sharing-scope>Shareable</res-sharing-scope>
</resource-ref>

</web-app>}
四。使用
public ActionForward dotest(ActionMapping mapping,ActionForm form,HttpServletRequest request,HttpServletResponse response){
try{              
System.out.println("test Start ==============");
Context cont = (Context) new InitialContext().lookup("java:comp/env");//固定
DataSource ds = (DataSource)cont.lookup("jdbc/testdt");
Connection con = ds.getConnection();
PreparedStatement ps = con.prepareStatement("select * from aaa");
ResultSet rs = ps.executeQuery();
while(rs.next()){
System.out.println("=========="+rs.getInt(1)+"  "+rs.getString(2));
}
　　　　con.close();//要记得关 不然会用尽连接池而报org.apache.commons.dbcp.SQLNestedException: Cannot get a connection, pool exhausted
System.out.println("====================");
}catch (Exception e) {
e.printStackTrace();
}
｝

要在web项目中运行，因为它是tomcat 建的连接，一般的java 类运行不了
开始以为 Ajax 不能调用，后来运行是可以的
第二步我用了网上的很多种方法都不行，试运行成功的只的这一种