测试的tomcat为apache-tomcat-6.0.18 ，数据库为mysql和oracle。
配置步骤如下：
1、把数据库的JDBC驱动放入D:\apache-tomcat-6.0.18\lib目录下
2、在D:\apache-tomcat-6.0.18\conf\web.xml文件中，将下面代码加入到web.xml中：
< resource - ref > < description > 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 > < resource - ref > < description > DB Connection </ description > < res - ref - name > jdbc / oracle </ res - ref - name > < res - type > javax.sql.DataSource </ res - type > < res - auth > Container </ res - auth > </ resource - ref >
3、在D:\apache-tomcat-6.0.18\conf\server.xml文件中,在Host节点下添加Context子节点，配置如下
< Context path = " /ljqtest " docBase = " ljqtest " debug = " 5 " reloadable = " true " crossContext = " true " > < Resource name = " jdbc/mysql " type = " javax.sql.DataSource " username = " root " password = " mysql " driverClassName = " org.gjt.mm.mysql.Driver " url = " jdbc:mysql://localhost:3306/shop " maxIdle = " 2 " maxWait = " 50 " maxActive = " 4 " > < parameter > < name > removeAbandoned </ name > < value > true </ value > </ parameter > </ Resource > < Resource name = " jdbc/oracle " type = " javax.sql.DataSource " username = " test " password = " test " driverClassName = " oracle.jdbc.driver.OracleDriver " url = " jdbc:oracle:thin:@localhost:1521:ORCL " maxIdle = " 2 " maxWait = " 50 " maxActive = " 4 " > < parameter > < name > removeAbandoned </ name > < value > true </ value > </ parameter > </ Resource > </ Context > </ Host >
或者
< Context path = " /uimcardprj " docBase = " uimcardprj " debug = " 5 " reloadable = " true " crossContext = " true " > < Resource name = " jdbc/ycxkDB " type = " javax.sql.DataSource " username = " ycxk " password = " xmzh " driverClassName = " oracle.jdbc.driver.OracleDriver " url = " jdbc:oracle:thin:@(DESCRIPTION =(ADDRESS = (PROTOCOL = TCP)(HOST = 134.128.48.250)(PORT = 1521))(CONNECT_DATA =(SERVER = DEDICATED)(SERVICE_NAME = orcl))) " maxIdle = " 2 " maxWait = " 50 " maxActive = " 4 " > </ Resource > </ Context > </ Host >
注意：path为D:\apache-tomcat-6.0.18\webapps目录下的工程名称
4、把web工程项目部署在D:\apache-tomcat-6.0.18\webapps目录下MysqlConn类：获取Mysql数据源
package com.ljq.test; import java.sql.Connection; import java.sql.SQLException; import javax.naming.Context; import javax.naming.InitialContext; import javax.sql.DataSource; public final class MysqlConn { // 懒汉式单例(使用时才new) private static MysqlConn instance = null ; MysqlConn() { } // 延迟初始化(用到的时候才加载)(推荐) // public static synchronized JdbcConn // getInstance(){}->这样不好，因为每调用一次就同步，效率非常低 public static MysqlConn getInstance() { if (instance == null ) { synchronized (MysqlConn. class ) { // 可能会产生并发的问题，我们对他进行同步 if (instance == null ) { instance = new MysqlConn(); } } } return instance; } private DataSource getDataSource() { DataSource ds = null ; try { Context ctx = new InitialContext(); ds = (DataSource) ctx.lookup( " java:comp/env/jdbc/mysql " ); } catch (Exception e) { System.out.println( " 数据源获取失败 " ); e.printStackTrace(); } return ds; } public Connection getConn() { Connection conn = null ; try { conn = getDataSource().getConnection(); } catch (SQLException e) { System.out.println( " 数据库连接失败 " ); e.printStackTrace(); } return conn; }}
OraclelConn类：获取Oracle数据源
package com.ljq.test; import java.sql.Connection; import java.sql.SQLException; import javax.naming.Context; import javax.naming.InitialContext; import javax.sql.DataSource; public final class OracleConn { // 懒汉式单例(使用时才new) private static OracleConn instance = null ; OracleConn() { } // 延迟初始化(用到的时候才加载)(推荐) // public static synchronized JdbcConn // getInstance(){}->这样不好，因为每调用一次就同步，效率非常低 public static OracleConn getInstance() { if (instance == null ) { synchronized (OracleConn. class ) { // 可能会产生并发的问题，我们对他进行同步 if (instance == null ) { instance = new OracleConn(); } } } return instance; } private DataSource getDataSource() { DataSource ds = null ; try { Context ctx = new InitialContext(); ds = (DataSource) ctx.lookup( " java:comp/env/jdbc/mysql " ); } catch (Exception e) { System.out.println( " 数据源获取失败 " ); e.printStackTrace(); } return ds; } public Connection getConn() { Connection conn = null ; try { conn = getDataSource().getConnection(); } catch (SQLException e) { System.out.println( " 数据库连接失败 " ); e.printStackTrace(); } return conn; }}
页面index.jsp:打印数据库连接对象
< body > mysql连接对象为： <% Connection conn = MysqlConn.getInstance().getConn(); %><%= conn %><% conn.close(); %>< br /> oracle连接对象为： <% Connection conn2 = MysqlConn.getInstance().getConn(); %><%= conn2 %><% conn2.close(); %>< br /> </ body >
