JAVA Tomcat configuration Jndi and use C3P0 connection pool __java

Configure MySQL to be taken in a jndi way when the Meta-inf folder creates the Jndi for the Context.xml configuration application. Advantages for each application of independent jndi.

The configuration file and its steps are as follows:

1, Meta-inf create the <context.xml content as follows:

<pre name= "code" class= "HTML" ><?xml version= "1.0" encoding= "UTF-8"?>
<Context>
< Resource
        name= "Jdbc/mysql"
        auth= "
        Container" factory= "Org.apache.naming.factory.BeanFactory" Type= "Com.mchange.v2.c3p0.ComboPooledDataSource"
        driverclass= "Com.mysql.jdbc.Driver"
        idleconnectiontestperiod= "acquireretryattempts=" "
        3"
        checkouttimeout= "10000"
        maxpoolsize= "50"
        minpoolsize= "2"
        acquireincrement= "2"
        user= "root"
        password= "root"
        jdbcurl= "Jdbc:mysql" ://127.0.0.1:3306/ccc?useunicode=true&characterencoding=utf-8 "/>
</Context>

2, add references in the Web.xml file in Web-inf:

<!--Oracle database Jndi Data Source reference--> <!--<resource-ref>--> <!--<description>oracle DB Connection </description>--> <!--<res-ref-name>oracleDataSource</res-ref-name>--> <!--<
Res-type>javax.sql.datasource</res-type>--> <!--<res-auth>Container</res-auth>--> <!--</resource-ref>--> <!--mysql database jndi data source Reference--> <Resource-ref> <Description>mysql DB connection</Description> <Res-ref-name>jdbc/mysql</Res-ref-name> <Res-type>javax.sql.datasource</Res-type> <Res-auth>container</Res-auth> </Resource-ref> <!--SQL Server database Jndi data source reference--> <!--<resource-ref>--> <!--<description>sqlserver DB Co
    Nnection</description>--> <!--<res-ref-name>sqlserverDataSource</res-ref-name>--> <!--<res-type>javax.sql.DataSource</res-type>--> <!--<res-auth>container</ Res-auth>--> <!--</resource-ref>-->

3, DAO (a servlet or specialized data access Class) read the configuration and its creation connection and DataSource

Import Sun.jdbc.odbc.ee.ConnectionPool;
Import javax.naming.*;
Import Javax.sql.DataSource;
Import java.sql.*;
Import java.sql.*;
Import java.sql.SQLException;
Import java.util.Hashtable;

/**
 * Created by Wuxituong on 2016-10-01.
 * * Public
class Sqldao {
    private static connectionpool instace;
    private static <pre style= "font-family: Song body; font-size:9pt; Background-color:rgb (255, 255, 255); ><span style= "Background-color: #e4e4ff;" >ComboPooledDataSource</span>

ds Get data source private static <span style= "Font-family:arial, Helvetica, Sans-serif;" >

Combopooleddatasource

</span><span style= "font-family:arial, Helvetica, Sans-serif;" >createdatasource () </span> {if (ds = null) {System.out.println ("DS created"); try {Context ct = new Initialco ntext (); if (ct = = null) System.out.println ("No Configuration Environment"); Context Envcontext = (context) ct.lookup ("java:/comp/env"); ds = (<span style= "font-family:arial, Helvetica, Sans-serif;" >

Combopooleddatasource

</span><span style= "font-family:arial, Helvetica, Sans-serif;" >) envcontext.lookup ("Jdbc/mysql"); Obtain data source </span>} catch (Namingexception e) {e.printstacktrace () by name return DS; ///Get Connection object from connection pool public static synchronized Connection getconnection () throws sqlexception,namingexception{Connection Con=null; try {System.out.print ("Preparing to get con");//Get Connection con= (Connection) CreateDataSource (). getconnection ();} catch (Exception e) {E . Printstacktrace (); System.out.print ("Get Connection failed.") "); } return con; //Free connection public static synchronized void freeconnection (Connection con) {try {con.close ();} catch (SQLException e) {E.P Rintstacktrace (); SYSTEM.OUT.PRINTLN ("Close connection failed.") "); } }}

4, use DAO Remember in use con must con.close () put the connection back to the connection pool, otherwise it will cause the connection is occupied complete, can not get con. Causing the server to reboot and release con

Public ResultSet getresultsetdata (String sql) {
        ResultSet rs= null;
        try {
            Statement sta =  con.createstatement ();
            rs = sta.executequery (sql);
            return  rs;
        } catch (Exception e) {
            System.out.println (e.getmessage ());
            return RS;
        }
    public int exesql (String sql) {
        try {
            Statement sta =  con.createstatement ();
            return  sta.executeupdate (SQL);
        catch (Exception e) {
            System.out.println (e.getmessage ());
            Return-1
        }
    }