Eclipse工程目录META-INF/context.xml。

<?xml version="1.0" encoding="UTF-8"?>
<Context>
    <Resource name="jdbc/myposdb" auth="Container" type="javax.sql.DataSource"
        maxTotal="100" maxIdle="30" maxWaitMillis="10000" username="pos"
        password="mypassword" driverClassName="org.mariadb.jdbc.Driver"
        url="jdbc:mariadb://localhost:3306/myposb?characterEncoding=utf-8" />
</Context>

工程目录WEB-INF/web.xml文件中添加。

  <resource-ref>
    <res-ref-name>jdbc/myposdb</res-ref-name>
    <res-type>javax.sql.DataSource</res-type>
    <res-auth>Container</res-auth>
  </resource-ref>

数据库连接工具类。

package leo.pos.server;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

import javax.naming.InitialContext;
import javax.naming.NamingException;
import javax.sql.DataSource;

import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;

public class JdbcManager {
    private static Logger logger = LogManager.getLogger();

    private static InitialContext context = null;

    public static Connection getConnection() {
        try {
            context = new InitialContext();
            DataSource ds = (DataSource) context.lookup("java:/comp/env/jdbc/myposdb");
            Connection conn = ds.getConnection();
            return conn;
        } catch (NamingException e) {
            logger.fatal("数据源配置错误。" + e.toString());
        } catch (SQLException e) {
            logger.fatal("数据库查询失败。" + e.toString());
        }
        return null;
    }

    public static void close(Connection conn) {
        if (conn != null) {
            try {
                conn.close();
            } catch (SQLException e) {
                logger.info("数据库Connction关闭异常。" + e.toString());
            }
        }
    }

    public static void close(PreparedStatement ps) {
        if (ps != null) {
            try {
                ps.close();
            } catch (SQLException e) {
                logger.info("数据库PreparedStatement关闭异常。" + e.toString());
            }
        }
    }

    public static void close(ResultSet rs) {
        if (rs != null) {
            try {
                rs.close();
            } catch (SQLException e) {
                logger.info("数据库ResultSet关闭异常。" + e.toString());
            }
        }
    }
}