dbhelp.java

本代码是一个权限管理系统源代码

/*
 * Created on 2007-4-30
 *
 * 
 * 
 */
package  com.seavision.PermissionManage.help;

import java.sql.Connection;
import java.sql.SQLException;
import java.text.SimpleDateFormat;
import java.util.Arrays;
import java.util.Date;

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

/**
 * @author Administrator
 *
 * 
 * 
 */
public class DBHelp {
	static DataSource datasource = null;
	static {
		

			
			try {

				Context initCtx = new InitialContext();
				Context envCtx = (Context) initCtx.lookup("java:comp/env");
				datasource =
					(DataSource) envCtx.lookup(
						SystemConfigData.getConfig("DBHelp.dataSource"));
				Connection conn = datasource.getConnection();
				

				if (conn != null) {
					conn.createStatement();
				}
				conn.close();
			} catch (Exception e) {
				e.printStackTrace();
			}
		
	}
	public static Connection getConnection() {
		try {
			return datasource.getConnection();
		} catch (SQLException e) {
			e.printStackTrace();
		}
		return null;
	}
	
	private static int count = 1;
	
	/**
	 * 日期+序列数
	 * @return
	 */
	public synchronized static String getID() {
		SimpleDateFormat sdf = new SimpleDateFormat("yyyyMMddHHmmss");
		String str = sdf.format(new Date()) + formatNumber(count,4,'0');
		if(count == 9999){
			count = 1;
		}else{
			++count;
		}
		
		return str;
	}
	
	/**
	 * 数字格式化
	 * @param in 要格式化的数字
	 * @param length 总长度
	 * @param code 填充符号
	 * @return
	 */
	static String formatNumber(int in,int length,char code){
		char[] c = new char[length];
		Arrays.fill(c,code);
		String ins = in + "";
		ins.getChars(0,ins.length(),c,c.length - ins.length());
		return new String(c);
	}
	
	public static String getInsertSQL(String configTbl,String configCols){
		
		String tbl = SystemConfigData.getConfig(configTbl);
		
		String cols =  SystemConfigData.getConfig(configCols);
		StringBuffer sb = new StringBuffer();
		sb.append("insert into ");
		sb.append(tbl);
		sb.append(" (");
		sb.append(cols);
		sb.append(") values (");
		int count  = cols.split(",").length;
		for(; count > 0 ;--count){
			if(count == 1)
				sb.append("?");
			else
				sb.append("?,");
		}
		sb.append(")");
		return sb.toString();
	}
}