dbmanager.java

大型数据库课程设计源码

/**
 * 
 */
package db;

import java.sql.*;
import java.util.ListIterator;
import java.util.Vector;


/**
 * @author ��־ΰ
 *
 */
public class DBManager {
	private static final String dbName="lzw";
	private static final String dbDriver="oracle.jdbc.driver.OracleDriver";
	private static final String dbUrl="jdbc:oracle:thin:@localhost:1521:"+dbName;
	private static final String user="system";
	private static final String password="system";
	private static Connection con;
	private static Statement stmt;
	private static ResultSet rs;
	private static ResultSetMetaData rsmd;
	private static CallableStatement cstmt;
	/**
	 * 
	 * @return
	 */
	public static Connection getConnection() {
		try {
			Class.forName(dbDriver);
			con=DriverManager.getConnection(dbUrl,user,password);
			stmt=con.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,
                    ResultSet.CONCUR_UPDATABLE);
		} catch (ClassNotFoundException e) {
			 
			System.out.println( "can not find the class");
			 
		} catch (SQLException e) {
			 
			System.out.println( "can not connect to database");
			//e.printStackTrace();
		}
		return con;
		
	}
	public static void callProc(Vector<String> v,String procedure){
		ListIterator it=v.listIterator();
		try {
			cstmt=con.prepareCall(procedure);
			while(it.hasNext()){
				//cstmt.set
			}
		} catch (SQLException e) {
			// TODO 自动生成 catch 块
			e.printStackTrace();
		}
	}
	/**
	 * 
	 * @param selectString
	 * @return
	 */
	public static ResultSet executeSelect(String selectString) {
		try {
			rs=stmt.executeQuery(selectString);
		} catch (SQLException e) {
			 
			//e.printStackTrace();
			System.out.println("select error");
		} 
		return rs;
		
	}
	public static int executeQuery(String selectString) {
		try {
			rs=stmt.executeQuery(selectString);
			if(rs.next())
				return 0;
		} catch (SQLException e) {
		 
			//e.printStackTrace();
			System.out.println("select error");
		} 
		return 1;
		
	}
	public static int execInsert(String insertString) {
		int n = 0;
		try {System.out.println("insert");
			  n=stmt.executeUpdate(insertString);
		} catch (SQLException e) {
		 
			e.printStackTrace();
		}
		return n;
		
	}
	public static int execUpdate(String update) {
		int n=0;
		try {
			  n=stmt.executeUpdate(update);
		} catch (SQLException e) {
 
			e.printStackTrace();
		}
		return n;
		
	}
	public static int execDel(String sql) {
		return execUpdate(sql);
	}
	public static void releaseCon() {
		if(stmt!=null) {
			try {
				stmt.close();
			} catch (SQLException e) {
				e.printStackTrace();
			}
			stmt=null;
		}
		if(con!=null) {
			try {
				con.close();
			} catch (SQLException e) {
				//e.printStackTrace();
				System.out.println("can not close connection.");
			}
			con=null;
		}
	}
	public static void execBatch(Vector<String> v) {
		int i=0;
		ListIterator it=v.listIterator();
			try {
				while(it.hasNext())
					//stmt.addBatch((String)v.get(i));
				stmt.executeUpdate((String)it.next());
			} catch (SQLException e) {
				e.printStackTrace();
			}
		
	}
	public static Vector getMeta(String tableName) {
		String sql="select * from "+" "+tableName;
		Vector<String> v=new Vector<String>();int i=1;
		
		try {
			rs=stmt.executeQuery(sql);
			
			rsmd=rs.getMetaData();
			int n=rsmd.getColumnCount();
			while(i<=n) {System.out.println(rsmd.getColumnName(i)+" "+i);
				v.add(rsmd.getColumnName(i++).toString());
			}
		} catch (SQLException e) {
			e.printStackTrace();
		}
		return v;
	}
	/**
	 * @param args
	 */
	public static void main(String[] args) {
		DBManager.getConnection();
		ResultSet rs=DBManager.executeSelect("select * from employee");
		try {
			while(rs.next())System.out.println(rs.getString(1));
		} catch (SQLException e) {
			e.printStackTrace();
		}
	}

}