db.java

《JSP通用模块及典型系统开发实例导航》源代码

package com.wxpn.tutorial.db;

import java.io.*;
import java.sql.*;
import java.util.*;
import javax.xml.parsers.*;

import org.w3c.dom.*;

/**
 * 描述: 数据库连接类 
 * Copyright (c) 2005-2008 Wang Xining
 * 
 * @author 王夕宁
 * @version 1.0
 */

public class DB {
	static String driver = null;

	static String server = null;

	static String dbuser = null;

	static String dbpassword = null;

	static int minconn = 0;

	static int maxconn = 0;

	static double maxconntime = 0.1D;

	static String log_properties = null;

	static ConnectionPool p = null;

	public static String FILE_SEPARATOR = System.getProperty("file.separator");

	public static void getAtrributes() {

		Document doc = null;
		try {
			File docFile = new File(System.getProperty("user.home")+FILE_SEPARATOR + "systemdb.xml");
			DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
			DocumentBuilder db = dbf.newDocumentBuilder();
			doc = db.parse(docFile);

			Element root = doc.getDocumentElement();

			NodeList dbChilds = root.getChildNodes();
			for (int i = 0; i < dbChilds.getLength(); i++) {
				if (dbChilds.item(i).getNodeName().equals("driver")) {
					driver = dbChilds.item(i).getFirstChild().getNodeValue();
				} else if (dbChilds.item(i).getNodeName().equals("server")) {
					server = dbChilds.item(i).getFirstChild().getNodeValue();
				} else if (dbChilds.item(i).getNodeName().equals("dbuser")) {
					dbuser = dbChilds.item(i).getFirstChild().getNodeValue();
				} else if (dbChilds.item(i).getNodeName().equals("dbpassword")) {
					dbpassword = dbChilds.item(i).getFirstChild() == null ? ""
							: dbChilds.item(i).getFirstChild().getNodeValue();
				} else if (dbChilds.item(i).getNodeName().equals("minconn")) {
					minconn = dbChilds.item(i).getFirstChild() == null ? 5
							: Integer.parseInt(dbChilds.item(i).getFirstChild()
									.getNodeValue());
				} else if (dbChilds.item(i).getNodeName().equals("maxconn")) {
					maxconn = dbChilds.item(i).getFirstChild() == null ? 20
							: Integer.parseInt(dbChilds.item(i).getFirstChild()
									.getNodeValue());
				} else if (dbChilds.item(i).getNodeName().equals("maxconntime")) {
					maxconntime = dbChilds.item(i).getFirstChild() == null ? 0.1D
							: Double.parseDouble(dbChilds.item(i)
									.getFirstChild().getNodeValue());
				}
			} // end for
		} catch (Exception e) {
			System.out.println("Problem parsing the file:" + e);
		}

	}

	/**
	 * Create a connectionpool
	 */
	public static ConnectionPool getConnPool() {
		try {
			if (p == null) {
				getAtrributes();
				p = new ConnectionPool(driver, server, dbuser, dbpassword,
						minconn, maxconn, maxconntime);
			}
			return p;
		} catch (Exception e) {
			e.printStackTrace();
		}

		return null;
	}

	public static void main(String[] args) {
		ConnectionPool connPool = DB.getConnPool();
		Connection conn = connPool.getConnection();
		Statement stmt = null;
		ResultSet rs = null;

		try {
			int nextMessageid = 0;
			String relative_path = null;

			String sql = "select * from userinfo";
			stmt = conn.createStatement();
			// stmt.addBatch(sql);
			// sql = "insert into
			// mms_user(messageid,emailid,messagename,sender,coypto,bcc,sendtime,size,totalnumber,priority,remark,content)
			// values('7','1','Fw: 中文标识
			// 57567567','<wxn1@localhost>','<12121@localhost>','','Sun Oct 03
			// 14:30:13 CST 2004','114421','2','3','','')";
			sql = new String(sql.getBytes("gb2312"), "8859_1");
			rs = stmt.executeQuery(sql);
			while (rs.next()) {
				System.out.println(rs.getString("UserName"));
			}
		} catch (SQLException sqlExc) {
			sqlExc.printStackTrace();
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			try {
				if (rs != null) {
					rs.close();
				}
				if (stmt != null) {
					stmt.close();
				}
				connPool.freeConnection(conn);
				System.out.println("free connection!");
			} catch (SQLException sqlExc) {
				sqlExc.printStackTrace();
			}

		}
	}

}