[JavaEE] tomcat internal connection pool, javaeetomcat

[JavaEE] tomcat internal connection pool, javaeetomcat

Under the META-INF directory, create context. xml

Obtain the data source in the program. Through jndi, this jndi must be obtained in the Servlet, and you need to configure web. xml so that the servlet can get the data source as soon as it starts.

Context. xml

<?xml version="1.0" encoding="utf-8"?><Context>    <Resource    name="mySource"    type="javax.sql.DataSource"    username="root"    password="root"    driverClassName="com.mysql.jdbc.Driver"    url="jdbc:mysql:///java"    maxActive="8"    maxIdle="4"    /></Context>

Package com. tsh. web; import java. io. IOException; import java. SQL. connection; import java. SQL. resultSet; import java. SQL. statement; import javax. naming. context; import javax. naming. initialContext; import javax. servlet. servletException; import javax. servlet. http. httpServlet; import javax. servlet. http. httpServletRequest; import javax. servlet. http. httpServletResponse; import javax. SQL. dataSource;/***/public class DataSourceTest extends HttpServlet {/***/public DataSourceTest () {super (); // TODO Auto-generated constructor stub}/***/protected void doGet (HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {// TODO Auto-generated method stub}/***/protected void doPost (HttpServletRequest request, HttpServletResponse response) throws ServletException, after IOException {}/*** is created, it starts */@ Override public void init () throws ServletException {try {// note the javax import package. naming. context; Context context = new InitialContext (); Context jndi = (Context) context. lookup ("java: comp/env"); DataSource source = (DataSource) jndi. lookup ("mySource"); // note the java import package. SQL. connection; Connection conn = source. getConnection (); // get the transmitter object Statement statement = conn. createStatement (); // obtain the result set object ResultSet resultSet=statement.exe cuteQuery ("select * from user"); // traverse while (resultSet. next () {String username = resultSet. getString ("username"); System. out. println (username);} // closes the resource resultSet. close (); statement. close (); conn. close ();} catch (Exception e) {e. printStackTrace ();}}}

Web. 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>