Exception Handling with Kotlin Exposed - 如何捕获违反唯一约束的异常？

Question

我在 table 的列中添加了唯一约束。当约束被违反时，它会抛出一个我无法捕获并传达给用户的异常。

Exposed: Transaction attempt #0 failed: java.sql.BatchUpdateException: Batch entry 0 INSERT INTO templates (created_at, is_deleted, name, sections) VALUES ('2018-10-03 16:31:25.732+05:30', 'FALSE', 'Template1', '[{"title":"Introduction"}]') RETURNING * was aborted: ERROR: duplicate key value violates unique constraint "templates_name_key" Detail: Key (name)=(Template1) already exists. Call getNextException to see other errors in the batch.. Statement(s): INSERT INTO templates (created_at, is_deleted, name, sections) VALUES (?, ?, ?, ?) ! org.postgresql.util.PSQLException: ERROR: duplicate key value violates unique constraint "templates_name_key" ! Detail: Key (name)=(Template1) already exists.

如何使用用户可读消息捕获此类 SQL 异常？
是否有捕获这些异常的最佳实践？
我们应该在交易内部还是外部捕获它们？有这样的必要吗？

下面是我试过的片段。

return try {
    val template: TemplateSerializer = transaction {
        val newTemplate = Template.insert(request)
        TemplateSerializer.serialize(newTemplate)
    }
    Response.status(201).entity(template).build()
} catch (e: Exception) {
    if(e is SQLIntegrityConstraintViolationException) {
        resourceLogger.error("SQL constraint violated")
    } else if(e is BatchUpdateException) {
        resourceLogger.error("SQL constraint violated")
    } else
        resourceLogger.error(e.message)
    Response.status(422).entity(mapOf("error" to true, "message" to "Insertion failed")).build()
}

根本没有打印消息SQL constraint violated。也尝试过使用不同的 Exception 类进行多次捕获。没有任何效果。

发送此类一般性错误消息无济于事。

Answer 1

Exposed throws ExposedSQLException 是 SQLException 的子类型，可以通过 causeByQueries() 函数访问最新执行的查询（可能导致原始异常）。原始异常可通过 cause 属性.

访问

return try {
    val template: TemplateSerializer = transaction {
        val newTemplate = Template.insert(request)
        TemplateSerializer.serialize(newTemplate)
    }
    Response.status(201).entity(template).build()
} catch (e: Exception) {
    val original = (e as? ExposedSQLException)?.cause
    when (original) {
      is SQLIntegrityConstraintViolationException -> 
        resourceLogger.error("SQL constraint violated")
      is BatchUpdateException -> 
        resourceLogger.error("SQL constraint violated")
      else ->
        resourceLogger.error(e.message)
    }
Response.status(422).entity(mapOf("error" to true, "message" to "Insertion failed")).build()

Answer 2

您可以检查 sqlState。

看起来像：

try {
        userService.insertUser(user)
    } catch (e: ExposedSQLException) {

        val isUniqueConstraintError = e.sqlState == "23505"
    }

您可以从那里获取正确的错误代码：

https://www.postgresql.org/docs/10/errcodes-appendix.html

Exception Handling with Kotlin Exposed - 如何捕获违反唯一约束的异常？

Exception Handling with Kotlin Exposed - How to catch unique constraint violation exception?

kotlin

kotlin-exposed