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