我的各种主键生成策略类

package com.generate;

import java.text.DecimalFormat;
import java.text.NumberFormat;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Random;
import java.util.UUID;

/**
 * 主键生成策略
 * @author zzq
 *
 */
public class Generator {

	private static SimpleDateFormat sdf = new SimpleDateFormat("yyyyMMddHHmmssSS");
	private static Random random = new Random();
	private static NumberFormat nf = new DecimalFormat("000");
	
	private static Map<String, IDTable> idTables = new HashMap<String, IDTable>();
	
	/**
	 * UUID主键生成策略
	 * @return 32位UUID
	 */
	public static String UUIDGenerator() {
		return UUID.randomUUID().toString();
	}
	
	/**
	 * COMB主键生成策略
	 * @return yyyyMMddHHmmssSS 17位时间 + 3位随机数
	 */
	public static String COMBGenerator() {
		String datetime = sdf.format(new Date());
		int end = random.nextInt(1000);
		nf.format(end);
		return datetime + end;
	}
	
	/**
	 * 第三方数据表主键生成策略
	 * @param table 第三方主键表名
	 * @param keyColumnName 主键表识别主键字段名
	 * @param keyValue 主键表识别主键值
	 * @param valueColumnName 主键值字段名
	 * @return 主键值
	 */
	public static synchronized long TableGenerator(String table, String keyColumnName, String keyValue, String valueColumnName) {
		
		String key = table + "/" + keyColumnName + "/" + keyValue + "/" + valueColumnName;
		IDTable idTable = idTables.get(key);
		
		if(null == idTable) {
			idTable = (new Generator()).new IDTable();
			idTables.put(key, idTable);
		}
		
		return idTable.getValue(table, keyColumnName, keyValue, valueColumnName);
	}
	
	/**
	 * 释放资源，将缓存的标识字段同步到数据库中
	 */
	public static synchronized void TableGeneratorClose() {
		
		for(Iterator<String> iter = idTables.keySet().iterator(); iter.hasNext(); ) {
			String key = iter.next();
			Generator.IDTable idTable = idTables.get(key);
			String[] str = key.split("/");
			idTable.destory(str[0], str[1], str[2], str[3]);
		}
	}
	
	/**
	 * 主键表(主要负责向数据库查询对应识别值的主键值) 加入缓存策略
	 * @author 朱志强
	 *
	 */
	public class IDTable {
		
		private long maxValue;
		private long nextValue;
		private static final long POOLSIZE = 10;
		private boolean isInit = false;
		
		public long getValue(String table, String keyName, String keyValue, String valueName) {
			
			if(false == isInit) {
				init(table, keyName, keyValue, valueName);
				isInit = true;
			}
			
			if(nextValue == maxValue) {
				query(table, keyName, keyValue, valueName);
			}
			nextValue++;
			return nextValue;
		}
		
		/**
		 * 初始化资源，将属于与数据表中的标识字段同步
		 * @param table
		 * @param keyName
		 * @param keyValue
		 * @param valueName
		 */
		public void init(String table, String keyName, String keyValue, String valueName) {
			
			StringBuffer sb = new StringBuffer("select ").append(valueName).append(" from ").append(table).append(" where ").append(keyName).append(" = '").append(keyValue).append("'");
			
			Long id = DBUtil.executeQuery(sb.toString());
			
			if(null != id) {
				nextValue = id;
				maxValue = id;
			}
		}
		
		public void query(String table, String keyName, String keyValue, String valueName) {
			
			StringBuffer sb = new StringBuffer("select ").append(valueName).append(" from ").append(table).append(" where ").append(keyName).append(" = '").append(keyValue).append("'");
			
			Long id = DBUtil.executeQuery(sb.toString());
			if(null == id) {
				sb = new StringBuffer("insert into ").append(table).append(" values('").append(keyValue).append("', ").append(POOLSIZE).append(")");
				DBUtil.executeUpdate(sb.toString());
				maxValue = POOLSIZE;
				nextValue = 0;
			} else {
				sb = new StringBuffer("update ").append(table).append(" set ").append(valueName).append("=").append(maxValue + POOLSIZE).append(" where ").append(keyName).append("='").append(keyValue).append("'");
				DBUtil.executeUpdate(sb.toString());
				maxValue += POOLSIZE;
			}
		}
		
		/**
		 * 释放资源，将缓存中的数据同步到数据库中
		 * @param table 
		 * @param keyName
		 * @param keyValue
		 * @param valueName
		 */
		public void destory(String table, String keyName, String keyValue, String valueName) {
		
			StringBuffer sb = new StringBuffer("select ").append(valueName).append(" from ").append(table).append(" where ").append(keyName).append(" = '").append(keyValue).append("'");
			
			Long id = DBUtil.executeQuery(sb.toString());
			if(null != id) {
				sb = new StringBuffer("update ").append(table).append(" set ").append(valueName).append("=").append(nextValue).append(" where ").append(keyName).append("='").append(keyValue).append("'");
				DBUtil.executeUpdate(sb.toString());
			}
		}
	}
	
	public static void main(String[] args) throws Exception {
		long id = Generator.TableGenerator("idtable", "keyname", "t_user", "id");
		System.out.println(id);
		
		id = Generator.TableGenerator("idtable", "keyname", "t_user", "id");
		System.out.println(id);
		
		id = Generator.TableGenerator("idtable", "keyname", "t_person", "id");
		System.out.println(id);
		
		id = Generator.TableGenerator("idtable", "keyname", "t_org", "id");
		System.out.println(id);
		
		Generator.TableGeneratorClose();
	}
}

package com.generate;

import java.io.InputStream;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Properties;

/**
 * 数据库连接工厂
 * @author zzq
 *
 */
public class ConnectionFactory {

	private static String USERNAME;
	
	private static String PASSWORD;
	
	private static String URL;
	
	private static String DRIVERNAME;
	
	static {
		try {
			Properties prop = new Properties();
			InputStream is = Thread.currentThread().getContextClassLoader().getResourceAsStream("jdbc.properties");
			prop.load(is);
			USERNAME = prop.getProperty("username");
			PASSWORD = prop.getProperty("password");
			URL = prop.getProperty("url");
			DRIVERNAME = prop.getProperty("drivername");
			
			is.close();
			
			Class.forName(DRIVERNAME);
		} catch (Exception e) {
			throw new RuntimeException("加载数据源配置文件失败", e);
		}
	}
	
	public static Connection getConnection() {
		Connection conn = null;
		try {
			conn = DriverManager.getConnection(URL, USERNAME, PASSWORD);
		} catch (Exception e) {
			throw new RuntimeException("获取数据库连接失败", e);
		}
		return conn;
	}
	
	public static void close(Connection conn) {
		if(null != conn) {
			try {
				conn.close();
			} catch (SQLException e) {
				e.printStackTrace();
			}
		}
	}
	
	public static void close(Statement stmt) {
		if(null != stmt) {
			try {
				stmt.close();
			} catch (SQLException e) {
				e.printStackTrace();
			}
		}
	}
	
	public static void close(ResultSet rs) {
		if(null != rs) {
			try {
				rs.close();
			} catch (SQLException e) {
				e.printStackTrace();
			}
		}
	}
}

public class DBUtil {

	public static int executeUpdate(String sql) {
		Connection conn = null;
		Statement stmt = null;
		try {
			conn = ConnectionFactory.getConnection();
			stmt = conn.createStatement();
			return stmt.executeUpdate(sql);
		} catch(SQLException e) {
			throw new RuntimeException("更新失败", e);
		} finally {
			ConnectionFactory.close(stmt);
			ConnectionFactory.close(conn);
		}
	}
	
	public static Long executeQuery(String sql) {
		
		Connection conn = null;
		Statement stmt = null;
		ResultSet rs = null; 
		try {
			conn = ConnectionFactory.getConnection();
			stmt = conn.createStatement();
			rs = stmt.executeQuery(sql);
			
			boolean isReturn = rs.next();
			if(isReturn == false) {
				return null;
			}
			
			return rs.getLong(1);
		} catch(SQLException e) {
			throw new RuntimeException("查询数据失败", e);
		} finally {
			ConnectionFactory.close(rs);
			ConnectionFactory.close(stmt);
			ConnectionFactory.close(conn);
		}
	}
}