使用第三方Java库，如com.jcraft.jsch，使用clojure [英] Using 3rd party java libraries, like com.jcraft.jsch, with clojure

问题描述

我正在尝试 clojure ，并试图获得使用第三方库的感觉。我已经能够下载一些源，捆绑到一个jar文件与leiningen，把它放在我的类路径和（使用lib.etc）在我的脚本。我也玩过java.lang。*中的对象。

I'm experimenting with clojure and am trying to get a feel for using 3rd party libraries. I've been able to download some source, bundle it into a jar file with leiningen, put it in my classpath and (use 'lib.etc) in my script. I've also played around with the objects in java.lang.*.

我没有在第三方Java上取得任何成功。

I haven't had any success with 3rd party java, though.

$ java -cp clojure.jar:clojure-contrib.jar:com.jcraft.jsch_0.1.31.jar clojure.main
Clojure 1.1.0
user=> (require 'com.jcraft.jsch)
java.io.FileNotFoundException: Could not locate com/jcraft/jsch__init.class or com/jcraft/jsch.clj on classpath:  (NO_SOURCE_FILE:0)

$ jar tf com.jcraft.jsch_0.1.31.jar | egrep "(init|clj)"
$

看起来像一个__init.class .clj文件必须创建。

It looks like an __init.class or .clj file must be created. Is this true, or is there some alternative way that pure java classes are supposed to be loaded?

推荐答案

对于java类，使用 import ：

For java classes use import:

(import java.util.ArrayList)

;// or use a prefix for multiple classes:
(import [java.util ArrayList Collection])

;// or preferably in the ns declaration:
(ns my.lib
  [:import [java.util ArrayList Collection]])

user=> (def al (ArrayList.))
#'user/al
user=> (.add al "hi")
true
user=> (.size al)
1

注意包和类名不需要引用自 import 是一个宏。

Note the package and class names do not need to be quoted since import is a macro.

也不等同于 import java。 util。*; 您需要指定要导入哪些类。

Also there is no equivalent to import java.util.*; You need to specify which classes you want to import.

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