clojure.core/import

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Type: macro Added: Clojure 1.0 Examples: 5 Runnable: 2

([& import-symbols-or-lists])

import-list => (package-symbol class-name-symbols*)

For each name in class-name-symbols, adds a mapping from name to the class named by package.name to the current namespace. Use :import in the ns macro in preference to calling this directly.

Examples

by nipra on 2010-07-13 . May have evaluation errors. ▶

(import java.util.Date) java.util.Date (def now (Date.)) #'user/now (str now) "Tue Jul 13 17:53:54 IST 2010"

by dale on 2011-01-03 ▶

;; You can import multiple classes at once. (import (java.util Date Calendar) (java.net URI ServerSocket) java.sql.DriverManager)

by klauern on 2011-11-11 ▶

;; importing multiple classes in a namespace (ns foo.bar (:import (java.util Date Calendar) (java.util.logging Logger Level)))

by phreed on 2017-10-16 . May have evaluation errors. ▶

;; For cases when 'import' does not do it for you, i.e. "live-coding" ;; You can use the DynamicClassLoader, ClassReader and the Resolver. (def dcl (clojure.lang.DynamicClassLoader.)) (defn dynamically-load-class! [class-loader class-name] (let [class-reader (clojure.asm.ClassReader. class-name)] (when class-reader (let [bytes (.-b class-reader)] (.defineClass class-loader class-name bytes ""))))) (dynamically-load-class! dcl "java.lang.Long") (dynamically-load-class! dcl 'org.joda.time.DateTime) ;; From that point the dynamically loaded class can be ;; used by the Reflector to invoke constructors, methods and to get fields.

by ooooak on 2020-01-28 . May have evaluation errors. ▶

(import [org.apache.commons.codec.digest DigestUtils]) (defn md5-hash [input] (DigestUtils/md5Hex input)) (md5-hash "hello world!") ;; fc3ff98e8c6a0d3087d515c0473f8677

Note by gstamp

Good description of use/require/import here:

http://blog.8thlight.com/articles/2010/12/6/clojure-libs-and-namespaces-require-use-import-and-ns

Note by TimMc

import will also accept vectors instead of lists, but I would discourage folks from doing so:

• It's undocumented.
• Lists and vectors have different meanings for require, so there's precedent for making a distinction.
• Lists have a distinguished first element, and so they indent more meaningfully here. :-P

Note by YizhePKU

You don't need to use import if you fully qualify the class name, e.g. (java.util.Date.).

See also

• clojure.core/require (4)
• clojure.core/use (1)
• clojure.core/ns (3)

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