Question

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，我看到它们通过转换为文本的函数得到简单的引号，使其只呈现文本。这是我正在使用的转换器和绑定。我这样做了吗？我如何通过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();
    }
}

Answer 1

根据我的理解，你想要自动发生两件事：

字符串绑定值应该用`"_id" : ObjectId("592595a1bca1350220027666"), "user_account" : "5-5XX4XX-X06", "Xns" : { "Xn" : [ { "date" : "2015-09-01", "narration" : "ATM/CASH WDL/01-01-10/17:48:45/0", "amount" : "-2500.00", "category" : "Others", "balance" : "110578.04", "_id" : ObjectId("592595a1bca13502200276ca") }, { "date" : "2015-09-04", "narration" : "EBA//20100104081107", "amount" : "-7206.12", "category" : "Others", "balance" : "103371.92", "_id" : Object Id("592595a1bca13502200276c9") }`函数

包装

这是“简单”的部分，你几乎做对了：

ST_GeomFromText()

多边形类型列应使用@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()); }函数

进行格式化

您（可能）不必在绑定内部执行任何特定操作，因为绑定不会影响任何不涉及绑定变量的表达式（例如，普通的列表达式）。

相反，您可能需要调整转换器（绑定中的转换器）才能读取从JDBC驱动程序返回的任何类型并将其转换为ST_AsWKT()

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

1 个答案: