tomcat7下JDNI连接池的配置

建立数据库连接是非常耗时耗资源的行为，因此一般服务器像Tomcat，Weblogic等都提供了数据库连接池功能。下面介绍在Tomcat7下如何进行配置连接池（不同版本的tomcat服务器配置略有不同）。

首先，在tomcat的context.xml文件中配置：

<code class="hljs fsharp has-numbering" style="display: block; padding: 0px; background-color: transparent; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-position: initial initial; background-repeat: initial initial;">     <Resource name=<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"jdbc/test"</span>         auth=<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"Container"</span>         <span class="hljs-class" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">type</span>=</span><span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"javax.sql.DataSource"</span>         driverClassName=<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"com.mysql.jdbc.Driver"</span>         url=<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"jdbc:mysql://localhost:3306/test"</span>         username=<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"root"</span>        password=<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"root"</span>         maxActive=<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"100"</span>         maxIdle=<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"30"</span>         maxWait=<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"10000"</span>/>    <ResourceLink <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">global</span>=<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"jdbc/test"</span> name=<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"jdbc/test"</span> <span class="hljs-class" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">type</span>=</span><span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"javax.sql.DataSource"</span>/> </code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; background-color: rgb(238, 238, 238); top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right;"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li></ul>

接着在web.xml中对其进行引用：

<code class="hljs xml has-numbering" style="display: block; padding: 0px; background-color: transparent; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-position: initial initial; background-repeat: initial initial;">    <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">resource-ref</span>></span>          <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">description</span>></span>JNDI DataSource<span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">description</span>></span>          <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">res-ref-name</span>></span>jdbc/test<span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">res-ref-name</span>></span>          <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">res-type</span>></span>javax.sql.DataSource<span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">res-type</span>></span>          <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">res-auth</span>></span>Container<span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">res-auth</span>></span>    <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">resource-ref</span>></span> </code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; background-color: rgb(238, 238, 238); top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right;"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li></ul>

注：注意其与tomcat要相适应

编写测试类：

<code class="hljs java has-numbering" style="display: block; padding: 0px; background-color: transparent; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-position: initial initial; background-repeat: initial initial;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">package</span> jnditest;<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> java.sql.Connection;  <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> javax.naming.Context;  <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> javax.naming.InitialContext;  <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> javax.sql.DataSource;  <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-class" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">class</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">ConnectionPool</span> {</span>      <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">private</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">static</span> Connection conn;      <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">static</span> Connection <span class="hljs-title" style="box-sizing: border-box;">getConn</span>(){          <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">try</span>{              Context ctx = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> InitialContext();              DataSource ds =             (DataSource)ctx.lookup(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"java:comp/env/jdbc/test"</span>);              System.out.println(ds);            conn = ds.getConnection();          }<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">catch</span>(Exception e){              e.printStackTrace();          }          <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span> conn;      }  }  </code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; background-color: rgb(238, 238, 238); top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right;"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li><li style="box-sizing: border-box; padding: 0px 5px;">21</li><li style="box-sizing: border-box; padding: 0px 5px;">22</li><li style="box-sizing: border-box; padding: 0px 5px;">23</li><li style="box-sizing: border-box; padding: 0px 5px;">24</li></ul>

在webContent下建立main.jsp文件：

<code class="hljs xml has-numbering" style="display: block; padding: 0px; background-color: transparent; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-position: initial initial; background-repeat: initial initial;"><span class="vbscript" style="box-sizing: border-box;"><%@ page language=<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"java"</span> contentType=<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"text/html; charset=UTF-8"</span>      pageEncoding=<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"UTF-8"</span>%></span>  <span class="vbscript" style="box-sizing: border-box;"><%@ page import=<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"jnditest.ConnectionPool,java.sql.Connection,java.sql.*"</span> %></span>  <span class="hljs-doctype" style="color: rgb(102, 0, 102); box-sizing: border-box;"><!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"></span>  <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">html</span>></span>  <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">head</span>></span>  <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">meta</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">http-equiv</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"Content-Type"</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">content</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"text/html; charset=UTF-8"</span>></span>  <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">title</span>></span>测试JNDI连接<span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">title</span>></span>  <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">head</span>></span>  <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">body</span>></span>  <span class="vbscript" style="box-sizing: border-box;"><%  ConnectionPool conn = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> ConnectionPool();  Connection conns = conn.getConn();  <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span>(<span class="hljs-literal" style="color: rgb(0, 102, 102); box-sizing: border-box;">null</span>!=conns){      out.println(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"数据库连接状态:<b>OK</b><hr />"</span>);      PreparedStatement pst = conns.prepareStatement(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"SELECT * FROM STUDENT"</span>);      ResultSet rs = pst.executeQuery();      <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">while</span>(rs.<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">next</span>()){          <span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">int</span> id =rs.getInt(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"ID"</span>);          <span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">String</span> name = rs.getString(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"NAME"</span>);          out.println(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"<b>id:</b>"</span>+id+<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"<br /><b>姓名:</b>"</span>+name+<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"<br /><b>性别:</b>"</span>+<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"<br />"</span>+<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"<hr />"</span>);      }  }<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">else</span>{      out.println(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"数据库连接状态:NO"</span>);  }  %></span>  <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">body</span>></span>  <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">html</span>></span>  </code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; background-color: rgb(238, 238, 238); top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right;"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li><li style="box-sizing: border-box; padding: 0px 5px;">21</li><li style="box-sizing: border-box; padding: 0px 5px;">22</li><li style="box-sizing: border-box; padding: 0px 5px;">23</li><li style="box-sizing: border-box; padding: 0px 5px;">24</li><li style="box-sizing: border-box; padding: 0px 5px;">25</li><li style="box-sizing: border-box; padding: 0px 5px;">26</li><li style="box-sizing: border-box; padding: 0px 5px;">27</li><li style="box-sizing: border-box; padding: 0px 5px;">28</li><li style="box-sizing: border-box; padding: 0px 5px;">29</li></ul>

最后，注意要将MySQL的驱动包加入到tomcat下的lib目录中。

配置完毕，在MySQL下建立表：

<code class="hljs sql has-numbering" style="display: block; padding: 0px; background-color: transparent; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-position: initial initial; background-repeat: initial initial;"><span class="hljs-operator" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">DROP</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">TABLE</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">IF</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">EXISTS</span> <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">`test`</span>.<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">`student`</span>;</span><span class="hljs-operator" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">CREATE</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">TABLE</span>  <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">`test`</span>.<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">`student`</span> (  <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">`id`</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span>(<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">11</span>) <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">NOT</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">NULL</span>,  <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">`name`</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">varchar</span>(<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">20</span>) <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">DEFAULT</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">NULL</span>,  <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">PRIMARY</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">KEY</span> (<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">`id`</span>)) ENGINE=InnoDB <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">DEFAULT</span> CHARSET=utf8;</span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; background-color: rgb(238, 238, 238); top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right;"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li></ul>

插入几条数据，启动服务器，输入URL地址，测试结果如下：

数据库连接状态:OK 
id:1 
姓名:张三 
性别: 
id:2 
姓名:李四 
性别: 
id:3 
姓名:王五 
性别:

注：

应还在tomcat的conf\Catalina\localhost目录下建立一份名称 
与web名相同内容与context.xml相同的文件，否则会出现 
org.apache.tomcat.dbcp.dbcp.SQLNestedException: Cannot 
create *JDBC driver of class ” for connect URL’null’异常，可能是由于tomcat（可能由于权限或者配置问题）无法将context.xml文件写入到conf\Catalina\localhost中的原因。