java 基于tomcat的数据源案例

1、在context中定义数据源

 <?xml version="1.0" encoding="UTF-8"?>
 <Context path="/testDs" reloadable="true"
 docBase="D:\eclipse-jee-mars-2-win32-x86_64\work_duct-support\testDs\base"
 workDir="D:\eclipse-jee-mars-2-win32-x86_64\work_duct-support\testDs\work" >
     <Resource
         name="jdbc/mysql"
         auth="Container"
         type="javax.sql.DataSource"
         maxActive="100"
         maxIdle="30"
         maxWait="10000"
         username="root"
         password="Isd@2014"
         driverClassName="com.mysql.jdbc.Driver"
         url="jdbc:mysql://172.16.10.163:3306/zhicall_hcrm?useUnicode=true&amp;characterEncoding=utf8" />
 </Context>

 <!--
 1、Resource必须配合Context配置，
 2、不同的部署方式，配置的Context不同，Resource配置的地方也不同，
 3、如果是在Catalina\localhost\下配置xml（如：testDs.xml），则xml配置参考以上配置
 4、把自个的WebAppProject里的/META-INF/context.xml的内容复制到$CATALINA_BASE/conf/context.xml里或者$CATALINA_BASE/conf/server.xml
 5、直接将自个的WebAppProject打包成WAR文件拷贝到$CATALINA_BASE/webapps目录里，tomcat启动后，自动会将WebAppProject里的/META-INF/context.xml文件内容复制到$CATALINA_BASE/conf/context.xml里
 6、conf的context.xml 的 <Context></Context>也可配置
 7、可在<CATALINA_HOME>/conf/server.xml 文件中的对应<Host>元素中如上配置<Resource>子元素以供Tomcat容器内的多个Web应用使用
 -->

2、在web.xml中配置

 <?xml version="1.0" encoding="UTF-8"?>
 <web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
     xmlns="http://java.sun.com/xml/ns/javaee"
     xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
     xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" version="3.0">
     <display-name>testDs</display-name>
     <servlet>
         <servlet-name>testServlet</servlet-name>
         <servlet-class>test_servlet_package.test_servlet</servlet-class>
     </servlet>
     <servlet-mapping>
         <servlet-name>testServlet</servlet-name>
         <url-pattern>/testServlet</url-pattern>
     </servlet-mapping>
     <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>
 </web-app>

3、在servlet中使用

 package test_servlet_package;
 import java.io.IOException;
 import java.sql.Connection;
 import java.sql.ResultSet;
 import java.sql.Statement;
 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 test_servlet extends HttpServlet {

     protected void doGet(HttpServletRequest req, HttpServletResponse res) throws ServletException, IOException {
         DataSource ds = null;
         try {
             InitialContext ctx = new InitialContext();
             ds = (DataSource) ctx.lookup("java:comp/env/jdbc/mysql");
             Connection conn = ds.getConnection();
             Statement stmt = conn.createStatement();
             String strSql = "select * from dim_code";
             ResultSet rs = stmt.executeQuery(strSql);
             while (rs.next()) {
                 System.out.println("name：" + rs.getString(1));
             }
             rs.close();
             stmt.close();
             conn.close();
         } catch (Exception ex) {
             ex.printStackTrace();
         }
     }
 }

总结：案例只是介绍一个数据源的简单使用、用于理解、方便后期调查使用