JDBC数据库连接+MySql

public class DataBaseUtil {
  //数据库连接工具包

   public static Connection DataBaseConnection(){
     
       String driver="com.mysql.jdbc.Driver";//驱动路径
       String url="jdbc:mysql://**"; //**为数据库地址
       String user="root";//访问数据库的用户名
       String password="111111";//数据库用户密码
        
       try{
              Class.forName("driver");//加载驱动
              Connection conn=DriverManager.getConnection(url,user,password);//创建数据库连接
              return conn ;
        }catch(Exception e){
             e.printStackTrace();    
        }
             return null ;
   }
    
   public static Statement getDefaultStatement() throws Exception{
 
       Connection conn = DataBaseUtil.getDefaultConnection();
       Statement stmt = conn.createStatement();//创建数据库操作对象
       return stmt ;
   }
       

   public static void close(Connection conn){

       try{
            if(null != conn && !conn.isClosed()){
                 conn.close();
       }catch(Exception e){
            e.printStackTrace();
       }
   }

}     

Public ResultSet exqueryInfo(){

   try{

        Statement statement = DataBaseUtil.getDefaultStatement();
        String sql="select * from 表名 where 字段1 = ‘" + 变量1 + "‘ and 字段2 = ‘"+ 变量2 + "‘";
        ResultSet rs=statement.executeQuery(sql);
        return rs;
   }catch(Exception e){
        e.printStackTrace();
   }
        return null ;    
}

public void updateAC(String a, String b, String c){
                
    String sql = "UPDATE common_tabBooked SET A=? , B=?  WHERE C = ?  "; //改
    
               
    try{
        Connection conn = DataBaseUtil.getDefaultConnection();
        PreparedStatement pstm = conn.prepareStatement(sql);            
        pstm.setString(1, a);
        pstm.setString(2, b);
        pstm.setString(3, c);
        pstm.executeUpdate();
                    
    }catch(Exception e){
        e.printStackTrace();
    }    
}

String sql="INSERT INTO 表名 (字段1,字段2,字段3,字段4,字段5) values(?,?,?,?,?)";

string sql = "select * from 表名 where 字段1 = ?";

string sql = "delete  from 表名 where 字段1 = ?";