Question

我有一个简单的DAO ns：

(ns   alavita.dao
  (:require
    [clojure.tools.logging    :as     log     ]
    [clojure.java.io          :as     io      ]
  )
  (:import
    [org.jdbi.v3.core Jdbi Handle]
  ))

(defn create
  (^Jdbi [^String url]
    (Jdbi/create url))
  (^Jdbi [^String url ^String username ^String password]
    (Jdbi/create url username password)))

(defn open
  ^Handle [^Jdbi jdbi]
  (.open jdbi))

尝试使用lib时：

alavita.core=> (def c (dao/create "jdbc:sqlite:/tmp/data.db"))
#'alavita.core/c
alavita.core=> (def h (dao/open c))
#'alavita.core/h
alavita.core=> (.execute h "show tables")

IllegalArgumentException No matching method found: execute for class org.jdbi.v3.core.Handle  clojure.lang.Reflector.invokeMatchingMethod (Reflector.java:53)

这有点奇怪，因为h肯定有.execute：

alavita.core=> (cli/all-methods h)
(.attach .begin .close .commit .createBatch .createCall .createQuery .createScript .createUpdate .execute .getConfig .getConnection .getExtensionMethod .getStatementBuilder .getTransactionIsolationLevel .inTransaction .isClosed .isInTransaction .isReadOnly .lambda$attach$3 .lambda$new$0 .lambda$useTransaction$1 .lambda$useTransaction$2 .prepareBatch .release .rollback .rollbackToSavepoint .savepoint .select .setConfig .setConfigThreadLocal .setExtensionMethod .setExtensionMethodThreadLocal .setReadOnly .setStatementBuilder .setTransactionIsolation .useTransaction)

不知道它横向走向何方。

open和create的类型：

alavita.core=> (type (dao/create "jdbc:sqlite:/tmp/data.db"))
org.jdbi.v3.core.Jdbi
alavita.core=> (type (dao/open c))
org.jdbi.v3.core.Handle

添加反射：

alavita.core=> (set! *warn-on-reflection* true)
true
alavita.core=> (.execute h "show tables")
Reflection warning, /private/var/folders/nr/g50ld9t91c555dzv91n43bg40000gn/T/form-init767780595230125901.clj:1:1 - call to method execute can't be resolved (target class is unknown).

IllegalArgumentException No matching method found: execute for class org.jdbi.v3.core.Handle  clojure.lang.Reflector.invokeMatchingMethod (Reflector.java:53)

Answer 1

如this port中所述，这是Java如何处理var-args的问题。您需要首先将var-args包装在数组中，而不是依赖于var-arg行为。

我建议编写一个Clojure函数来处理这个问题：

(defn execute [^Handle h, ^String sql, & args]
  (.execute h sql (into-array Object args)))

而是使用它。

找不到与JDBI和Clojure匹配的方法

1 个答案: