在META-INF的目录下,新建context.xml
在程序中获取数据源,通过jndi,这个jndi必须在Servlet中才能获取,并且需要配置web.xml使servlet一启动就拿到数据源
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 {
}
/**
* 创建后就会启动
*/
@Override
public void init() throws ServletException {
try {
//注意导包javax.naming.Context;
Context context= new InitialContext();
Context jndi=(Context) context.lookup("java:comp/env");
DataSource source =(DataSource) jndi.lookup("mySource");
//注意导包 java.sql.Connection;
Connection conn=source.getConnection();
//获取传输器对象
Statement statement=conn.createStatement();
//获取结果集对象
ResultSet resultSet=statement.executeQuery("select * from user");
//遍历
while(resultSet.next()){
String username=resultSet.getString("username");
System.out.println(username);
}
//关闭资源
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>