使用servlet连接数据库

使用servlet连接数据库主要配置web.xml的<servlet>元素和<servlet-mapping>元素。

1、web.xml配置

<servlet>
<display-name>This is the description of my J2EE component</display-name>
<description>This is the description of my J2EE component</description>
<servlet-name>DBServlet</servlet-name>
<servlet-class>jijian.test.DBServlet</servlet-class>
<init-para>
<param-name>driverName</param-name>
<param-value>org.postgresql.Driver</param-value>
</init-para>
<init-para>
<param-name>username</param-name>
<param-value>itnms</param-value>
</init-para>
<init-para>
<param-name>password</param-name>
<param-value>itnms</param-value>
</init-para>
<init-param>
<param-name>dbName</param-name>
<param-value>itnms</param-value>
</init-param>
</servlet>

<servlet-mapping>
<servlet-name>DBServlet</servlet-name>
<url-pattern>/servlets/DBServlet</url-pattern>
</servlet-mapping>

2、servlet.java文件

package jijian.test;
...

public class DBServlet extends HttpServlet{ //定义一个继承HttpServlet的公有类
ServletConfig config=null; //定义一个ServletConfig对象
private String driverName=""; //定义私有字符串常量并初始化
private String username=""; //定义的数据库用户名
private String password=""; //定义的数据库连接密码
private String dbName=""; //定义的数据库名
private Connection conn; //初始化连接
private Statement stmt; //初始化数据库操作
ResultSet rs=null; //初始化结果集
public void init(ServletConfig config)throws ServletException{
super.init(config); //继承父类的init()方法
this.config=config; //获取配置信息
driverName=config.getInitParameter("driverName");//从配置文件中获取JDBC驱动名
username=config.getInitParameter("username"); //获取数据库用户名
password=config.getInitParameter("password"); //获取数据库连接密码
dbName=config.getInitParameter("dbName"); //获取要连接的数据库
}
public void doGet(HttpServletRequest req,HttpServletResponse resp)throws IOException,ServletException{
. . .
}

public void doPost(HttpServletRequest req,HttpServletResponse resp)throws IOException,ServletException{
. . .
}

public void destory(){
. . .
}
}