jdbc连接

妖狐艹你老母 2023-10-18 10:20 129阅读 0赞

// 通过jdbc查询数据库
    
    		// 数据库连接
    		Connection connection = null;
    
    		// 预编译的statement，向数据库发起请求
    		PreparedStatement preparedStatement = null;
    
    		// 结果集
    		ResultSet resultSet = null;
    		
    		//区域列表
    		List<Area> list = new ArrayList<Area>();
    
    		try {
    			// 加载数据库驱动
    			Class.forName("com.mysql.jdbc.Driver");
    
    			// 获取数据库连接
    			connection = DriverManager.getConnection(
    					"jdbc:mysql://localhost:3306/webservice", "root", "mysql");
    			
    			//构造 sql
    			String sql = "SELECT areaid,areaname,arealevel,parentid FROM AREA WHERE parentid=? LIMIT ?,?";
    			
    			//创建statement对象
    			preparedStatement = connection.prepareStatement(sql);
    			
    			//向statement中设置参数
    			preparedStatement.setString(1, parentid);
    			start  = start -1;
    			int len = end - start;
    			preparedStatement.setInt(2, start);
    			preparedStatement.setInt(3, len);
    			
    			//向数据库发起请求
    			resultSet = preparedStatement.executeQuery();
    			
    			//解析resultSet
    			while(resultSet.next()){
    				Area area = new Area();
    				//获取的数据内容根据接口内容去获取
    				String areaid_l = resultSet.getString("areaid");
    				String areaname_l = resultSet.getString("areaname");
    				String arealevel_l = resultSet.getString("arealevel");
    				String parentid_l = resultSet.getString("parentid");
    				
    				area.setAreaid(areaid_l);
    				area.setArealevel(arealevel_l);
    				area.setParentid(parentid_l);
    				area.setAreaname(areaname_l);
    				
    				list.add(area);
    			}
    		} catch (Exception e) {
    			// TODO Auto-generated catch block
    			e.printStackTrace();
    		}finally{
    			//释放资源
    			if(resultSet!=null){
    				resultSet.close();
    			}
    			if(preparedStatement!=null){
    				preparedStatement.close();
    			}
    			if(connection!=null){
    				connection.close();
    			}
    		}
    
    		return list;