db.java

一个很不错的开发系统的程序

package com.bjsxt.bbs;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

public class DB {
	public static Connection getConn() {
		Connection conn = null;
		try {
			Class.forName("com.mysql.jdbc.Driver");
			conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/bbs", "root" , "123456");
		} catch (ClassNotFoundException e) {
			e.printStackTrace();
		} catch (SQLException e) {
			e.printStackTrace();
		}
		return conn;
	}
	
	public static Statement createStmt(Connection conn) {
		Statement stmt = null;
		try {
			stmt = conn.createStatement();
		} catch (SQLException e) {
			e.printStackTrace();
		}
		return stmt;
	}
	
	public static ResultSet executeQuery(Statement stmt, String sql) {
		ResultSet rs = null;
		try {
			rs = stmt.executeQuery(sql);
		} catch (SQLException e) {
			e.printStackTrace();
		}
		return rs;
	}
	
	/*public static ResultSet executeQuery(Connection conn, String sql) {
		Statement stmt = null;
		ResultSet rs = null;
		try {
			stmt = conn.createStatement();
			rs = stmt.executeQuery(sql);
		} catch (SQLException e) {
			e.printStackTrace();
		}
		
//		finally {
//			close(stmt);
//		}
		
		
		return rs;
	}*/
	
	public static int executeUpdate(Connection conn, String sql) {
		int ret = 0;
		Statement stmt = null;
		try {
			stmt = conn.createStatement();
			ret = stmt.executeUpdate(sql);
		} catch (SQLException e) {
			e.printStackTrace();
		} finally {
			close(stmt);
		}
		return ret;
	}
	
	public static PreparedStatement prepareStmt(Connection conn, String sql) {
		PreparedStatement pstmt = null;
		try {
			pstmt = conn.prepareStatement(sql);
		} catch (SQLException e) {
			e.printStackTrace();
		}
		return pstmt;
	}
	
	public static PreparedStatement prepareStmt(Connection conn, String sql, int autoGeneratedKeys) {
		PreparedStatement pstmt = null;
		try {
			pstmt = conn.prepareStatement(sql, autoGeneratedKeys);
		} catch (SQLException e) {
			e.printStackTrace();
		}
		return pstmt;
	}
	
	public static void close(Connection conn) {
		if(conn != null) {
			try {
				conn.close();
			} catch (SQLException e) {
				e.printStackTrace();
			}
			conn = null;
		}
	}
	
	public static void close(Statement stmt) {
		if(stmt != null) {
			try {
				stmt.close();
			} catch (SQLException e) {
				e.printStackTrace();
			}
			stmt = null;
		}
	}
	
	public static void close(ResultSet rs) {
		if(rs != null) {
			try {
				rs.close();
			} catch (SQLException e) {
				e.printStackTrace();
			}
			rs = null;
		}
	}
}