Java在Web应用中嵌入H2数据库教程

import java.sql.SQLException;
import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;
import org.h2.tools.Server;

/**
* @ClassName: H2DBServerStartListener
* @Description: 用于启动H2数据库服务的监听器，在应用系统初始化时就启动H2数据库的服务
* @author: 孤傲苍狼
* @date: 2014-12-20 下午11:43:39
*
*/
public class H2DBServerStartListener implements ServletContextListener {

    //H2数据库服务器启动实例
    private Server server;
    /*
     * Web应用初始化时启动H2数据库
     */
    public void contextInitialized(ServletContextEvent sce) {
        try { 
            System.out.println("正在启动h2数据库...");
            //使用org.h2.tools.Server这个类创建一个H2数据库的服务并启动服务，由于没有指定任何参数，那么H2数据库启动时默认占用的端口就是8082
            server = Server.createTcpServer().start();
            System.out.println("h2数据库启动成功...");
        } catch (SQLException e) { 
            System.out.println("启动h2数据库出错：" + e.toString()); 
            e.printStackTrace(); 
            throw new RuntimeException(e); 
        } 
    }

    /*
     * Web应用销毁时停止H2数据库
     */
    public void contextDestroyed(ServletContextEvent sce) {
        if (this.server != null) {
            // 停止H2数据库
            this.server.stop();
            this.server = null;
        }
    }
}

import java.util.UUID;

/**
* @ClassName: H2DBFunctionExt
* @Description: 针对H2数据库函数的扩展
* @author: 孤傲苍狼
* @date: 2014-12-20 下午11:20:34
*
*/
public class H2DBFunctionExt {

    /**
    * 用法：SELECT uuid();
    * H2数据库注册uuid函数：CREATE ALIAS uuid FOR "h2db.function.ext.H2DBFunctionExt.uuid";
    * @Method: uuid
    * @Description: 实现MySQL数据库的uuid函数，用于生成UUID
    * @Anthor:孤傲苍狼
    *
    * @return
    */
    public static String uuid(){
        return UUID.randomUUID().toString();
    }
}

import java.net.InetAddress;
import java.net.UnknownHostException;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.UUID;

/**
* @ClassName: H2DBFunctionExt
* @Description: 针对H2数据库函数的扩展
* @author: 孤傲苍狼
* @date: 2014-12-20 下午11:20:34
*
*/
public class H2DBFunctionExt {

    /**
    * 用法：SELECT uuid();
    * H2数据库注册uuid函数：CREATE ALIAS IF NOT EXISTS uuid FOR "h2db.function.ext.H2DBFunctionExt.uuid";
    * @Method: uuid
    * @Description: 实现MySQL数据库的uuid函数，用于生成UUID
    * @Anthor:孤傲苍狼
    *
    * @return
    */
    public static String uuid(){
        return UUID.randomUUID().toString();
    }

    /**
    * H2数据库注册currentTime函数：CREATE ALIAS IF NOT EXISTS currentTime FOR "h2db.function.ext.H2DBFunctionExt.now";
    * @Method: now
    * @Description: 实现MySQL数据库的now()函数，用于生成当前系统时间
    * @Anthor:孤傲苍狼
    *
    * @return
    */
    public static String now(){
        return new Date().toLocaleString();
    }
   
    /**
     * H2数据库注册IP函数：CREATE ALIAS IF NOT EXISTS IP FOR "h2db.function.ext.H2DBFunctionExt.getIp";
    * @Method: getIp
    * @Description:
    * @Anthor:孤傲苍狼
    *
    * @return
    */
    public static String getIp(){
        try {
            InetAddress addr = InetAddress.getLocalHost();
            //获得本机IP
            return addr.getHostAddress();
        } catch (UnknownHostException e) {
            e.printStackTrace();
            return "未知的IP地址";
        }
    }
   
    /**
    * H2数据库注册date_format函数：CREATE ALIAS IF NOT EXISTS date_format FOR "h2db.function.ext.H2DBFunctionExt.date_format";
    * @Method: date_format
    * @Description: 实现MySQL数据库的date_format()函数，用于格式化日期
    * @Anthor:孤傲苍狼
    * @param date
    * @param pattern
    * @return
    */
    public static String date_format(String date,String pattern){
        if (date != null) {
            SimpleDateFormat sdf = new SimpleDateFormat(pattern);
            try {
                Date temp = sdf.parse(date);
                return sdf.format(temp);
            } catch (ParseException e) {
                e.printStackTrace();
            }
        }
        return "";
    }
}

import java.sql.Connection;
import java.sql.Statement;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;

import me.gacl.util.JdbcUtil;

/**
* @ClassName: RegisterH2ExtFuncServlet
* @Description:注册H2数据库的扩展函数
* @author: 孤傲苍狼
* @date: 2014-12-20 下午11:47:03
*
*/
public class RegisterH2ExtFuncServlet extends HttpServlet {

    /**
    * @Field: serialVersionUID
    */
    private static final long serialVersionUID = 4379248469825545593L;

    public void init() throws ServletException {
        //1、注册uuid函数的SQL语句
        String sql1 = "CREATE ALIAS IF NOT EXISTS uuid FOR "h2db.function.ext.H2DBFunctionExt.uuid"";
        //2、注册currentTime函数的SQL语句
        String sql2 = "CREATE ALIAS IF NOT EXISTS currentTime FOR "h2db.function.ext.H2DBFunctionExt.now"";
        //3、注册IP函数的SQL语句
        String sql3 = "CREATE ALIAS IF NOT EXISTS IP FOR "h2db.function.ext.H2DBFunctionExt.getIp"";
        //4、注册date_format函数的SQL语句
        String sql4 = "CREATE ALIAS IF NOT EXISTS date_format FOR "h2db.function.ext.H2DBFunctionExt.date_format"";
        Connection connection = null;
        Statement stmt = null;
        try {
            //获取数据库连接
            connection = JdbcUtil.getConnection();
            //获取Statement对象
            stmt = connection.createStatement();
            //添加要执行的SQL
            stmt.addBatch(sql1);
            stmt.addBatch(sql2);
            stmt.addBatch(sql3);
            stmt.addBatch(sql4);
            //批量执行上述的4条SQL
            stmt.executeBatch();
            System.out.println("H2数据库扩展函数注册成功！");
            stmt.clearBatch();
        } catch (Exception e) {
            System.out.println("H2数据库扩展函数注册失败！");
            e.printStackTrace();
        }finally{
            try {
                stmt.close();
                connection.close();
            } catch (Exception e2) {
                e2.printStackTrace();
            }
        }
    }
}

import java.io.InputStream;
import java.sql.Connection;
import java.util.Properties;
import org.h2.jdbcx.JdbcConnectionPool;

public class JdbcUtil {

    /**
     * H2数据库自带的连接池
     */
    private static JdbcConnectionPool cp = null;
   
    static{
        try {
            //加载src目录下的h2config.properties
            InputStream in = JdbcUtil.class.getClassLoader().getResourceAsStream("h2config.properties");
            Properties prop = new Properties();
            prop.load(in);
            //创建数据库连接池
            cp = JdbcConnectionPool.create(prop.getProperty("JDBC_URL"), prop.getProperty("USER"), prop.getProperty("PASSWORD"));
        } catch (Exception e) {
            System.out.println("连接池初始化异常");
            e.printStackTrace();
        }
    }
   
    /**
    * @Method: getConnection
    * @Description:获取数据库连接
    * @Anthor:孤傲苍狼
    * @return
    * @throws Exception
    */
    public static Connection getConnection() throws Exception{
        return cp.getConnection();
    }

    public static JdbcConnectionPool getCp() {
        return cp;
    }
}