JAVA内嵌数据库H2的使用入门

H2数据库是开源的，非常适合做嵌入式数据库使用，尤其用java编码的时候。

H2的优势：
　　　　1、h2采用纯Java编写，因此不受平台的限制。
　　　　2、h2只有一个jar文件，十分适合作为嵌入式数据库试用。
　　　　3、h2提供了一个十分方便的web控制台用于操作和管理数据库内容。

一、所需工具：

　　JDK

　　h2-1.4.x.jar

二、写代码如下：

package com.my.enter;

import java.sql.Connection;
import java.sql.SQLException;

import org.h2.jdbcx.JdbcConnectionPool;

public class ConnectionPool {
    private static ConnectionPool cp = null;
    private JdbcConnectionPool jdbcCP = null;

    private ConnectionPool() {
        String dbPath ="./config/test";
        jdbcCP = JdbcConnectionPool.create("jdbc:h2:" + dbPath, "sa", "");
        jdbcCP.setMaxConnections(50);
    }

    public static ConnectionPool getInstance() {
        if (cp == null) {
            cp = new ConnectionPool();
        }
        return cp;
    }

    public Connection getConnection() throws SQLException {
        return jdbcCP.getConnection();
    }
}

实例化时若数据库test.mv.db不存在，则会创建，路径是src的同级目录config/test.mv.db;

三、使用数据库：

package com.my.enter;

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

public class CommonDao {

    public static void crateTable() throws SQLException {
        Connection conn = null;
        Statement stmt = null;
        try {
            conn = ConnectionPool.getInstance().getConnection();
            DatabaseMetaData meta = conn.getMetaData();

            ResultSet rsTables = meta.getTables(null, null, "WEATHERINFO",
                    new String[] { "TABLE" });
            if (!rsTables.next()) {
                stmt = conn.createStatement();
                stmt.execute("CREATE TABLE WEATHERINFO(WEATHERSTR VARCHAR(1024),LASTMODIFYTIME VARCHAR(1024),STATUS VARCHAR(1024),PRIMARY KEY(WEATHERSTR,LASTMODIFYTIME))");
            }
            rsTables.close();
        } finally {
            releaseConnection(conn, stmt, null);
        }
    }

    public static void addInfo(String str, long lastModifyTime,
            String status) throws SQLException {
        Connection conn = null;
        PreparedStatement stmt = null;
        try {
            conn = ConnectionPool.getInstance().getConnection();

            stmt = conn
                    .prepareStatement("INSERT INTO WEATHERINFO VALUES(?,?,?)");
            stmt.setString(1, str);
            stmt.setString(2, String.valueOf(lastModifyTime));
            stmt.setString(3, status);
            stmt.execute();

        } finally {
            releaseConnection(conn, stmt, null);
        }
    }

    public static boolean isInfoExits(String filePath, long lastModifyTime)
            throws SQLException {
        Connection conn = null;
        PreparedStatement stmt = null;
        ResultSet rs = null;
        try {
            conn = ConnectionPool.getInstance().getConnection();
            stmt = conn
                    .prepareStatement("SELECT WEATHERSTR FROM WEATHERINFO WHERE STATUS=? AND LASTMODIFYTIME=?");
            stmt.setString(1, filePath);
            stmt.setString(2, String.valueOf(lastModifyTime));
            rs = stmt.executeQuery();
            return rs.next();
        } finally {
            releaseConnection(conn, stmt, rs);
        }
    }

    private static void releaseConnection(Connection conn, Statement stmt,
            ResultSet rs) throws SQLException {
        if (rs != null) {
            rs.close();
        }
        if (stmt != null) {
            stmt.close();
        }
        if (conn != null) {
            conn.close();
        }
    }

}

实现对数据库的操作 包括建表，新增数据，查询等操作；

以上，应该是入门了！