在Tomcat中配置数据库连接池
1、在Tomcat的安装目录 apache-tomcat\conf\server.xml 中找到<GlobalNamingResources>标签，并加入一个子标签<Resource>具体配置如下：
<Resource name="jdbc/webdb" auth="Container"
type="javax.sql.DataSource"
driverClassName="com.mysql.jdbc.Driver"
url="jdbc:mysql://localhost:3306/webdb?characterEncoding=UTF-8"
username="root"
password="root"
maxActive="200"
maxIdle="50"
maxWait="3000"/>
2、在Tomcat的安装目录 apache-tomcat\conf\Catalina\localhost中建立一个wx.xml文件 内容如下驼捕总
<Context path="/wx" docBase="wx" debug="0">
<ResourceLink name="jdbc/webdb" global="jdbc/webdb" type="javax.sql.DataSource"/>
</Context>
3、建立数据库如下
4、建立web工程如下
package test;
import java.io.IOException;
import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class hello extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
response.setContentType("text/html;charset=UTF-8");
PrintWriter out = response.getWriter();
try {
javax.naming.Context ctx=new javax.naming.InitialContext();
javax.sql.DataSource ds=(javax.sql.DataSource)ctx.lookup("java:/comp/env/jdbc/webdb");
Connection conn=ds.getConnection();
PreparedStatement pstmt=conn.prepareStatement("select*from t_dictionary");
ResultSet rs=pstmt.executeQuery();
StringBuilder table=new StringBuilder();
table.append("<table border='1'>篇物");
table.append("哨裁<tr><td>书名</td><td>价格</td><tr>");
while(rs.next()){
table.append("<tr><td>"+rs.getString("english")+"</tr></td>");
table.append("<tr><td>"+rs.getString("chinese")+"</td></tr>");
}
table.append("</table>");
out.println(table.toString());
pstmt.close();
} catch (Exception e) {
out.println(e.getMessage());
}
}
}
5、web.xml的配置
<?xml version="1.0" encoding="UTF-8"?>
<web-app version="3.0"
xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd">
<servlet>
<description>This is the description of my J2EE component</description>
<display-name>This is the display name of my J2EE component</display-name>
<servlet-name>hello</servlet-name>
<servlet-class>test.hello</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>hello</servlet-name>
<url-pattern>/servlet/hello</url-pattern>
</servlet-mapping>
6、测试如下
