配置连接池（终于弄好了～～）

server.xml

<Context path="/bookstore" docBase="bookstore" debug="0"     reloadable="true">      <Resource          name="jdbc/BookDB"           auth="Container"          type="javax.sql.DataSource"          driverClassName="com.mysql.jdbc.Driver"           maxActive="100"          maxIdle="30" maxWait="10000"          url="jdbc:mysql://localhost:3306/bookdb?autoReconnect=true"          username="dbuser"           password="1234"           removeAbandoned="true"/>     </Context>

web.xml

<?xml version="1.0" encoding="UTF-8"?>    <web-app>     <welcome-file-list>         <welcome-file>Dbjsp1.jsp</welcome-file>         <welcome-file>index.htm</welcome-file>         <welcome-file>index.jsp</welcome-file>     </welcome-file-list>  <resource-ref>   <description>DB connection</description>   <res-ref-name>jdbc/BookDB</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>

//数据库连接代码

Connection con;   Statement stmt;   ResultSet rs;      Context ctx=new InitialContext();   DataSource ds=(DataSource)ctx.lookup("java:comp/env/jdbc/BookDB");   con=ds.getConnection();      stmt=con.createStatement();