如何在Java中将Javascript对象格式化为多边形

Question

我想将Javascript对象存储为Mysql数据库中的多边形。我可以定义x和y的起点和终点来给我四个角：

var polygon = [
    xstart +' '+ ystart,
    xend +' '+ ystart,
    xend +' '+ yend,
    xstart +' '+ yend,
    xstart +' '+ ystart
];

我可以将此对象格式化为字符串

polygon = "POLYGON'("+ polygon.toString() +")',0";

当我将其插入到Mysql数据库中时

INSERT INTO `caption` (`caption_id`, `caption_area`) VALUES (NULL, 'POLYGON\'(0.28540775806607094 0.3356063323928521,0.35407728596306665 0.3356063323928521,0.35407728596306665 0.45764498813705906,0.28540775806607094 0.45764498813705906,0.28540775806607094 0.3356063323928521)\',0')

查询失败

#1416 - Cannot get geometry object from data you send to the GEOMETRY field

如何格式化Javascript对象或查询，以将多边形正确插入数据库中？

Answer 1

在mysql中，您必须使用ST_GeomFromText

polygon = "ST_GeomFromText('POLYGON("+ polygon.toString() +")')";

我不确定您到底需要什么数字0。

Answer 2

POLYGON是来自Open Geospatial Consortium OpenGIS中定义的MySQL空间扩展的空间数据类型。您可以在MySQL中为四个多边形定义空间数据类型，例如：

    LINESTRING(0.28540775806607094 0.3356063323928521, 0.35407728596306665      0.3356063323928521, 0.35407728596306665 0.45764498813705906, 0.28540775806607094 0.45764498813705906, 0.28540775806607094 0.3356063323928521)

因此，它使用以下命令将caption_area存储为TEXT：

    SET @g = 'LINESTRING(0.28540775806607094 0.3356063323928521, 0.35407728596306665 0.3356063323928521, 0.35407728596306665 0.45764498813705906, 0.28540775806607094 0.45764498813705906, 0.28540775806607094 0.3356063323928521)';

    INTO `caption` (`caption_id`, `caption_area`) VALUES (NULL,ST_AsText(ST_GeomFromText(@g)));