[Java EE] Tomcat internal connection pool

under the Meta-inf directory, create a new context.xml

Get the data source in the program, through jndi, this jndi must be available in the Servlet , and you need to configure Web. xml get the servlet to the data source as soon as it starts

Context.xml

<?XML version= "1.0" encoding= "Utf-8"?><Context>    <Resourcename= "MySource"type= "Javax.sql.DataSource"username= "root"Password= "root"Driverclassname= "Com.mysql.jdbc.Driver"URL= "Jdbc:mysql:///java"maxactive= "8"Maxidle= "4"    /></Context>

 PackageCom.tsh.web;Importjava.io.IOException;Importjava.sql.Connection;ImportJava.sql.ResultSet;Importjava.sql.Statement;ImportJavax.naming.Context;ImportJavax.naming.InitialContext;Importjavax.servlet.ServletException;ImportJavax.servlet.http.HttpServlet;Importjavax.servlet.http.HttpServletRequest;ImportJavax.servlet.http.HttpServletResponse;ImportJavax.sql.DataSource;/** */ Public classDatasourcetestextendsHttpServlet {/**     */     Publicdatasourcetest () {Super(); //TODO auto-generated Constructor stub    }    /**     */    protected voidDoget (HttpServletRequest request, httpservletresponse response)throwsservletexception, IOException {//TODO auto-generated Method Stub    }    /**     */    protected voidDoPost (HttpServletRequest request, httpservletresponse response)throwsservletexception, IOException {}/*** It will start when created*/@Override Public voidInit ()throwsservletexception {Try {            //Note the Guide pack javax.naming.Context;Context context=NewInitialContext (); Context Jndi= (Context) context.lookup ("Java:comp/env")); DataSource Source= (DataSource) jndi.lookup ("MySource"); //Note the Guide pack java.sql.Connection;Connection conn=source.getconnection (); //get The transmitter objectStatement statement=conn.createstatement (); //get result Set objectResultSet resultset=statement.executequery ("SELECT * from User"); //Traverse             while(Resultset.next ()) {String username=resultset.getstring ("username");            SYSTEM.OUT.PRINTLN (username); }            //Close ResourceResultset.close ();            Statement.close ();        Conn.close (); } Catch(Exception e) {e.printstacktrace (); }    }}

Xml

    <servlet>        <Servlet-name>Datasourcetest</Servlet-name>        <Servlet-class>Com.tsh.web.DataSourceTest</Servlet-class>        <Load-on-startup>1</Load-on-startup>    </servlet>    <servlet-mapping>        <Servlet-name>Datasourcetest</Servlet-name>        <Url-pattern>/servlet/datasourcetest</Url-pattern>    </servlet-mapping>

[Java EE] Tomcat internal connection pool