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！