java JDBC-连接、关闭代码的封装和资源文件的使用

忘是亡心i 2021-07-24 15:39 344阅读 0赞

jdbc工具类封装
    public class jdbcutil { 
    	static Properties pros=null; //帮助读取和处理资源文件
    	
    	static {   //加载类的时候调用
    		pros=new Properties();
    		try { 
    			pros.load(Thread.currentThread().getContextClassLoader().getResourceAsStream("db.properties"));
    		} catch (IOException e) { 
    			e.printStackTrace();
    		}
    		
    	}
    		public static void main(String[] args) { 
    			
    			
    		}
    		
    		//与数据库建立连接类，返回Connection对象
    		public static Connection getMysqlConn()
    		{ 
    
    			
    			try { 
    				Class.forName(pros.getProperty("mysqlDriver"));
    				return DriverManager.getConnection(pros.getProperty("mysqlURL"),
    						pros.getProperty("mysqlUser"),pros.getProperty("mysqlPwd"));
    			} catch (ClassNotFoundException e) { 
    				e.printStackTrace();
    			} catch (SQLException e) { 
    				e.printStackTrace();
    			}
    			return null;
    		}
    		
    		
    		//关闭连接类
    		public static void close(ResultSet rs,Statement ps,Connection conn)
    		{ 
    			try { 
    				if(null!=rs)
    				{ 
    					rs.close();
    				}
    			}catch(SQLException e)
    			{ 
    				e.printStackTrace();
    			}
    			try { 
    				if(null!=ps)
    				{ 
    					ps.close();
    				}
    			}catch(SQLException e)
    			{ 
    				e.printStackTrace();
    			}
    			
    			try { 
    				if(null!=conn)
    				{ 
    					conn.close();
    				}
    			}catch(SQLException e)
    			{ 
    				e.printStackTrace();
    			}
    
    		}
    		//重载关闭类 
    		public static void close(Statement ps,Connection conn)
    		{ 
    			try { 
    				if(null!=ps)
    				{ 
    					ps.close();
    				}
    			}catch(SQLException e)
    			{ 
    				e.printStackTrace();
    			}
    			
    			try { 
    				if(null!=conn)
    				{ 
    					conn.close();
    				}
    			}catch(SQLException e)
    			{ 
    				e.printStackTrace();
    			}
    
    		}
    		//重载关闭类
    		public static void close(Connection conn)
    		{ 
    
    			try { 
    				if(null!=conn)
    				{ 
    	**加粗样式**				conn.close();
    				}
    			}catch(SQLException e)
    			{ 
    				e.printStackTrace();
    			}
    
    		}
    
    }
    
    **资源文件**用文件名.properties左下角properties打开
    name		 value
    mysqlDriver  com.mysql.jdbc.Driver
    mysqlURL	 jdbc:mysql://localhost:3306/test
    mysqlUser	 root
    mysqlPwd	 dyl123
    
    **客户端调用**
    
    public class Demo11 { 
    	public static void main(String[] args) { 
    		Connection conn=null;
    		PreparedStatement ps=null;
    		ResultSet rs=null;
    		
    		try { 
    			
    			conn=jdbcutil.getMysqlConn();
    
    			ps=conn.prepareStatement("insert into t_user(username)values (?)");
    			ps.setString(1, "gaogao");
    			ps.execute();
    			
    			
    		}catch(Exception e)
    		{ 
    			e.printStackTrace();
    		}finally { 
    			jdbcutil.close(conn);
    		}
    	}
    }