Question

我有一个复合类型的数组。让我们说它看起来像这样：

CREATE TYPE hobbie AS (
  name VARCHAR,
  description VARCHAR
);

CREATE TABLE person (
    id SERIAL,
    hobbie hobbie[]
);

现在我需要从postgres中检索人的爱好并将它们转换为java对象，如下所示：

public class Hobbie {
    String name;
    String description;
}

我能用jdbc做的唯一事情是将数组get转换为带有爱好的结果集，就像这个("basketball","the best game")一样。如何使用jdbc将其转换为java对象？

更新

这是我使用jdbc处理postgres数组的代码：

ResultSet hobbies = rs.getArray("hobbies").getResultSet
while (hobbies.next()){
    hobbies.getString(1) // returns some index or I don't know
    hobbies.getObject(2) // returns PgValue with value == String ("basketball","the best game")
    hobbies.getObject(2)  // obviously returns String with the same value
    hobbies.getArray(2)   // returns something strange
    hobbies.getObject(2, Hobbie.class) // throws unsupported conversion to class com.test.Hobbie. Maybe there is a way to register custom converter, but I didn't find any
 }

Answer 1

像这样查询表

SELECT (r).* FROM (SELECT unnest(hobbie) AS r 
from person) AS hobbies;

它会像爱好者一样输出爱好。 JDBC转换应该直接从那里开始。

如何使用jdbc和Postgres将复合类型的数组转换为java对象的数组？

1 个答案: