java jdbc封装

 

package com.sunshine.dao;

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

public class DB {
 public static Connection getConnection() {
  Connection conn = null; 
  //1.注册驱动
  try {
   Class.forName("com.mysql.jdbc.Driver");
  } catch (ClassNotFoundException e) {
   // TODO Auto-generated catch block
   System.out.println("驱动异常！");
   e.printStackTrace();
  }
  //2.获取连接
  try {
   conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/miaoling","root","901106");
  } catch (SQLException e) {
   // TODO Auto-generated catch block
   System.out.println("getConnection异常！");
   e.printStackTrace();
  }
  return conn;
 }
 //sql:insert,update,delete
 public static int executeUpdate(String sql) {
  Connection conn = DB.getConnection();
  Statement stmt = null;
  try {
   stmt = conn.createStatement();
  } catch (SQLException e) {
   // TODO Auto-generated catch block
   System.out.println("createStatement异常！");
   e.printStackTrace();
  }
  int result = 0;
  try {
   result = stmt.executeUpdate(sql);
  } catch (SQLException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
   System.out.println("executeUpdate异常！");
  }
  DB.close(conn, stmt, null); 
  return result;
 }
 public static Statement getStatement(Connection conn) {
  try {
   return conn.createStatement();
  } catch (SQLException e) {
   // TODO Auto-generated catch block
   System.out.println("createStatement异常！");
   e.printStackTrace();
  }
  return null;
 }
 //sql:select
 public static ResultSet executeQuery(Connection conn,Statement stmt,String sql) {
  ResultSet rs = null;
  try {
   rs = stmt.executeQuery(sql);
  } catch (SQLException e) {
   // TODO Auto-generated catch block
   System.out.println("executeQuery异常！");
   e.printStackTrace();
  }
  return rs;
 }
 
 public static void close(Connection conn,Statement stmt,ResultSet rs){
  if (rs!=null){
   try {
    rs.close();
   } catch (SQLException e) {
    e.printStackTrace();
   }
  }
  if (stmt!=null){
   try {
    stmt.close();
   } catch (SQLException e) {
    e.printStackTrace();
   }
  }
  if(conn!=null){
   try {
    conn.close();
   } catch (SQLException e) {
    e.printStackTrace();
   }
  }
 }
}