[javaEE] tomcat內部串連池，javaeetomcat

[javaEE] tomcat內部串連池，javaeetomcat

在META-INF的目錄下，建立context.xml

在程式中擷取資料來源，通過jndi，這個jndi必須在Servlet中才能擷取，並且需要配置web.xml使servlet一啟動就拿到資料來源

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, IOException {    }    /**     * 建立後就會啟動     */    @Override    public void init() throws ServletException {        try {            //注意導包javax.naming.Context;            Context context= new InitialContext();            Context jndi=(Context) context.lookup("java:comp/env");            DataSource source =(DataSource) jndi.lookup("mySource");            //注意導包 java.sql.Connection;            Connection conn=source.getConnection();            //擷取傳輸器對象            Statement statement=conn.createStatement();            //擷取結果集對象            ResultSet resultSet=statement.executeQuery("select * from user");            //遍曆            while(resultSet.next()){                String username=resultSet.getString("username");                System.out.println(username);            }            //關閉資源            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>