conn.java

在管理员表中初始插入数据 usn: admin, pwd: 21232F297A57A5A743894A0E4A801FC3 初始用户账号/密码: admin (密码为 md5 加密) SRC

import java.sql.*;

public class Conn {
        static String DBDriver = "sun.jdbc.odbc.JdbcOdbcDriver";
        static String ConnStr = "jdbc:odbc:Driver={SQL Server};Server=(local);uid=sa;pwd=;Database=图书";
        static ResultSet rs = null;
        static private Connection conn = null;

        public static Connection ConnDB() {
        	try {
				if (conn != null && !conn.isClosed())
					return conn;
			} catch (SQLException e1) {
				e1.printStackTrace();
			}
            try {
                 Class.forName(DBDriver);
                 conn = DriverManager.getConnection(ConnStr);
            } catch (SQLException e) {
            	System.out.println(e.getMessage());
            } catch (Exception e) {
            	System.out.println(e.getMessage());
            }
            return conn;
        }

        public static Connection getConn() {
        	try {
				if (conn == null || conn.isClosed())
					return ConnDB();
			} catch (SQLException e) {
				e.printStackTrace();
			}
            return conn;
        }

        public static void exec(String sql) {
                try {
                        Statement stm = conn.createStatement();
                        stm.execute(sql);
                        stm.close();
                } catch (Exception e) { e.printStackTrace(); }
        }

        public static ResultSet query(String sql) {
                try {
                        Statement stm = conn.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE, ResultSet.CONCUR_UPDATABLE);
                        // Statement stm=conn.createStatement();
                        rs = stm.executeQuery(sql);
                        //stm.close();
                } catch (Exception e) { e.printStackTrace(); }
                return rs;
        }

        public static void close() {
            if (conn == null) return;
            try {
            	if (!conn.isClosed())
            		conn.close();
            } catch (SQLException e) {
            	e.printStackTrace();
            }
        }
        
        public static String getBookInfo(String bid) {
        	String tmp = "";
    		String sql = "select AA.*, BB.类名 from (select a.*, b.出版社  from (";
    		sql += "select * from 图书信息 where id=" + bid;
    		sql += ") as a left join (select * from 出版社) as b on (a.出版社ID = b.id)) as AA ";
    		sql += "left join (select * from 类别) as BB on (AA.类别ID = BB.id)";
    		rs = Conn.query(sql);
    		try {
    			if (rs.next()) {
    				tmp = "书号:" + bid;
    				tmp += "\r\n书名:" + rs.getString("书名");
    				tmp += "\r\n出版号:" + rs.getString("出版号");
    				tmp += "\r\n价格:" + rs.getString("价格");
    				tmp += "\r\n作者:" + rs.getString("作者");
    				tmp += "\r\n出版日期:" + rs.getString("出版日期");
    				tmp += "\r\n数量:" + rs.getString("数量");
    				tmp += "\r\n出版社:" + rs.getString("出版社");
    				tmp += "\r\n类别:" + rs.getString("类名");
    			}
    			rs.close();
    		} catch (SQLException e1) {
    			e1.printStackTrace();
    		}
    		return tmp;
        }
        
        public static String getReader(String rid) {
        	String tmp = "";
    		String sql = "select 姓名 from 读者 where id=" + rid;
    		rs = Conn.query(sql);
    		try {
    			if (rs.next()) {
    				tmp = "读者号:" + rid;
    				tmp += "\r\n名字:" + rs.getString("姓名");
    			}
    			rs.close();
    		} catch (SQLException e1) {
    			e1.printStackTrace();
    		}
    		return tmp;
        }
}