tomcat连接池配置 --详解

lijm1522

　　
context.xml中的配置

<Context path="/DBTest" docBase="DBTest"
debug="5" reloadable="true" crossContext="true">
<!—注意到这里的DBTest了吧，这就是要求大家建立DBTest目录的原因。-->
<Logger className="org.apache.catalina.logger.FileLogger"
prefix="localhost_DBTest_log." suffix=".txt"
timestamp="true"/>
<Resource name="jdbc/TestDB"
auth="Container"
type="javax.sql.DataSource"/>
<ResourceParams name="jdbc/TestDB">
<parameter>
<name>factory</name>
<value>org.apache.commons.dbcp.BasicDataSourceFactory</value>
</parameter>
<!-- Maximum number of dB connections in pool. Make sure you
configure your mysqld max_connections large enough to handle
all of your db connections. Set to 0 for no limit.
-->
<parameter>
<name>maxActive</name>
<value>100</value>
</parameter>
<!-- Maximum number of idle dB connections to retain in pool.
Set to 0 for no limit.
-->
<parameter>
<name>maxIdle</name>
<value>30</value>
</parameter>
<!-- Maximum time to wait for a dB connection to become available
in ms, in this example 10 seconds. An Exception is thrown if
this timeout is exceeded.  Set to -1 to wait indefinitely.
-->
<parameter>
<name>maxWait</name>
<value>10000</value>
</parameter>
<!-- MySQL dB username and password for dB connections  -->
<parameter>
<name>username</name>
<value>javauser</value>
<!—数据库用户名-->
</parameter>
<parameter>
<name>password</name>
<value>javadude</value>
<!—数据库密码-->
</parameter>
<!-- Class name for the old mm.mysql JDBC driver - uncomment this entry and comment next
if you want to use this driver - we recommend using Connector/J though
<parameter>
<name>driverClassName</name>
<value>org.gjt.mm.mysql.Driver</value>
</parameter>
这里面是被注释的，因为以前连接mysql是这样连接的，现在建议用下面的方法，自己可以看到。
-->
<!-- Class name for the official MySQL Connector/J driver -->
<parameter>
<name>driverClassName</name>
<value>com.mysql.jdbc.Driver</value>
</parameter>
<!-- The JDBC connection url for connecting to your MySQL dB.
The autoReconnect=true argument to the url makes sure that the
mm.mysql JDBC Driver will automatically reconnect if mysqld closed the
connection.  mysqld by default closes idle connections after 8 hours.
-->
<parameter>
<name>url</name>
<value>jdbc:mysql://localhost:3306/javatest?autoReconnect=true</value>
<!--这是数据库的地址，也可以不要这么繁琐，改为
jdbc:mysql://localhost/javatest即可,javatest为数据库名-->
</parameter>
</ResourceParams>
</Context>

　　2. web.xml 中的配置

<?xml version="1.0" encoding="ISO-8859-1"?>
<web-app xmlns="http://java.sun.com/xml/ns/j2ee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee
http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd"  version="2.4">
<description>MySQL Test App</description>
<resource-ref>
<description>DB Connection</description>
<res-ref-name>jdbc/TestDB</res-ref-name>
<res-type>javax.sql.DataSource</res-type>
<res-auth>Container</res-auth>
</resource-ref>
</web-app>
　　
3. java中使用的代码

try
{
Context initCtx=new InitialContext();
DataSource ds = (DataSource)initCtx.lookup("java:comp/env/jdbc/TestDB");
Connection conn=ds.getConnection();
out.println("data from database:<br>");
Statement stmt=conn.createStatement();
ResultSet rs =stmt.executeQuery("select id, foo, bar from testdata");
while(rs.next())
{
out.println(rs.getInt("id"));
out.println(rs.getString("foo"));
out.println(rs.getString("bar"));
}
rs.close();
stmt.close();
}
catch(Exception e)
{
e.printStackTrace();
}