MySQL POLYGON ←→ Jts Polygon with JOOQ (as WKT)

Posted 2023-03-28

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【中文标题】MySQL POLYGON ←→ Jts Polygon with JOOQ (as WKT)【英文标题】： 【发布时间】：2017-10-19 21:10:08 【问题描述】：

我正在尝试在使用 jOOQ (3.9.x) 时在 mysql POLYGON 类型和 Jts Polygon 之间进行无缝转换。理想情况下，我只想将数据库中的 WKT（众所周知的文本）解析为 Jts 类型。但是，生成的查询不起作用，我看到它们在转换为文本的函数周围获得了简单的引号，将其呈现为文本。这是我正在使用的转换器和绑定。我这样做对吗？我应该如何通过 ST_AsWKT 和 ST_GeomFromText 进行转换？

public class PolygonConverter implements Converter<Object, Polygon> 


    /**
     * Convert WK string into Polygon
     */

    @Override
    public Polygon from(Object databaseObject) 
        if (databaseObject == null) 
            return null;
        
        String wkString = databaseObject.toString();
        WKTReader reader = JtsSpatialContext.GEO.getWktShapeParser();
        try 
            Polygon poly = (Polygon)reader.parse(wkString);
            return poly;
         catch (java.text.ParseException e) 
            throw new IllegalArgumentException(e);
        
    

    @Override
    public Object to(Polygon userObject) 
        if (userObject == null) 
            return null;
        
        return userObject.toString();
    

    @Override
    public Class<Object> fromType() 
        return Object.class;
    

    @Override
    public Class<Polygon> toType() 
        return Polygon.class;

绑定：

public class MySQLPolygonBinding implements Binding<Object, Polygon> 
    @Override
    public Converter<Object, Polygon> converter() 
        return new PolygonConverter();
    

    @Override
    public void sql(BindingSQLContext<Polygon> ctx) throws SQLException 
        ctx.render().visit(DSL.sql("ST_AsWKT(?)"));
    

    @Override
    public void register(BindingRegisterContext<Polygon> ctx) throws SQLException 
        throw new SQLFeatureNotSupportedException();
    

    @Override
    public void set(BindingSetStatementContext<Polygon> ctx) throws SQLException 
        String resultStr = null;
        Object obj = ctx.convert(converter()).value();
        if (obj != null) 
            resultStr = String.format("ST_GeomFromText('%s')", obj,toString() );
        
        ctx.statement().setObject(ctx.index(), resultStr);
    

    @Override
    public void set(BindingSetSQLOutputContext<Polygon> ctx) throws SQLException 
        throw new SQLFeatureNotSupportedException();
    

    @Override
    public void get(BindingGetResultSetContext<Polygon> ctx) throws SQLException 
        ctx.convert(converter()).value(ctx.resultSet().getString(ctx.index()));
    

    @Override
    public void get(BindingGetStatementContext<Polygon> ctx) throws SQLException 
        ctx.convert(converter()).value(ctx.statement().getString(ctx.index()));
    

    @Override
    public void get(BindingGetSQLInputContext<Polygon> ctx) throws SQLException 
        throw new SQLFeatureNotSupportedException();

【问题讨论】：

您尝试生成的预期 SQL 字符串是什么？类似INSERT INTO table_test (poly ) VALUES (ST_GeomFromText ( 'POLYGON (00,11,00)')); SELECT ST_AsWKT(table_test.poly) from poly WHERE ... 【参考方案1】：

请注意，从 jOOQ 3.16 (see #982) 开始，jOOQ 开箱即用地支持各种流行的 GIS 实现。

据我了解，您希望自动发生两件事：

字符串绑定值应该用`ST_GeomFromText()` 函数包装

这是“简单”的部分，你几乎做对了：

@Override
public void sql(BindingSQLContext<Polygon> ctx) throws SQLException 
    ctx.render()
       .sql("ST_GeomFromText(")
       // This will use your converter to convert from a Polygon to "Object"
       // prior to binding the variable
       .visit(DSL.val(ctx.convert(converter()).value()))
       .sql(")");



@Override
public void set(BindingSetStatementContext<Polygon> ctx) throws SQLException 
    // No wrapping of the bind variable in functions can be done here!
    ctx.statement().setString(ctx.index(), ctx.convert(converter()).value());