运行 Leiningen 创建的 JAR 文件答案

【问题标题】：Running a JAR file created by Leiningen运行 Leiningen 创建的 JAR 文件
【发布时间】：2012-01-26 17:05:04
【问题描述】：

我在 project.clj 文件中有以下代码：

(defproject pinger "0.0.1-SNAPSHOT"
  :description "A website availability tester"
  :dependencies [[org.clojure/clojure "1.3.0"]]
  :main pinger.core)

(ns pinger.core
  (:import (java.net URL HttpURLConnection))
  (:gen-class))

(defn response-code [address]
  (let [conn ^HttpURLConnection (.openConnection (URL. address))
    code (.getResponseCode conn)]
    (when (< code 400)
      (-> conn .getInputStream .close))
    code))

(defn available? [address]
  (= 200 (response-code address)))

(defn -main []
  (let [addresses '("http://google.com"
            "http://amazon.com"
            "http://google.com/badurl")]
    (while true
      (doseq [address addresses]
    (println (available? address)))
      (Thread/sleep (* 1000 60)))))

我创建了一个 uberjar：

C:\Documents and Settings\vreinpa\My Documents\Books\ProgrammingClojure\code\src
\pinger>lein uberjar
Cleaning up.
Copying 1 file to C:\Documents and Settings\vreinpa\My Documents\Books\Programmi
ngClojure\code\src\pinger\lib
Warning: *classpath* not declared dynamic and thus is not dynamically rebindable
, but its name suggests otherwise. Please either indicate ^:dynamic *classpath*
or change the name.
Copying 1 file to C:\Documents and Settings\vreinpa\My Documents\Books\Programmi
ngClojure\code\src\pinger\lib
Created C:\Documents and Settings\vreinpa\My Documents\Books\ProgrammingClojure\
code\src\pinger/pinger-0.0.1-SNAPSHOT.jar
Including pinger-0.0.1-SNAPSHOT.jar
Including clojure-1.3.0.jar
Created C:\Documents and Settings\vreinpa\My Documents\Books\ProgrammingClojure\
code\src\pinger/pinger-0.0.1-SNAPSHOT-standalone.jar

然后我尝试运行该 uberjar 并收到以下错误：

C:\Documents and Settings\vreinpa\My Documents\Books\ProgrammingClojure\code\src
\pinger>java -jar pinger-0.0.1-SNAPSHOT-standalone.jar
Exception in thread "main" java.lang.NoClassDefFoundError: pinger/core
Caused by: java.lang.ClassNotFoundException: pinger.core
        at java.net.URLClassLoader$1.run(Unknown Source)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.net.URLClassLoader.findClass(Unknown Source)
        at java.lang.ClassLoader.loadClass(Unknown Source)
        at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
        at java.lang.ClassLoader.loadClass(Unknown Source)
Could not find the main class: pinger.core. Program will exit.

我在这里做错了什么？

【问题讨论】：

标签： clojure leiningen uberjar

【解决方案1】：

正如我所说的in response to your other question，project.clj 文件不是放置源代码的地方 - project.clj 由 leiningen 加载以设置您的项目配置，并且不能保证将任意代码放在那里完全，并且肯定会搞乱您在其中定义的命名空间的加载。按照conventions for source libs 将文件放在项目树中的 src 目录下。

【讨论】：

这是“Programming Clojure”一书中的一个示例，其中隐含地告诉将代码放入project.clj。我想，作者在写这一章时并没有太努力。

【解决方案2】：

$ lein new pinger
$ cd pinger
$ lein deps

pinger/project.clj

(defproject pinger "0.0.1-SNAPSHOT"
  :description "A website availability tester"
  :dependencies [[org.clojure/clojure "1.3.0"]]
  :main pinger.core)

pinger/src/pinger/core.clj

(ns pinger.core
  (:import (java.net URL HttpURLConnection))
  (:gen-class))

(defn response-code [address]
  (let [conn ^HttpURLConnection (.openConnection (URL. address))
    code (.getResponseCode conn)]
    (when (< code 400)
      (-> conn .getInputStream .close))
    code))

(defn available? [address]
  (= 200 (response-code address)))

(defn -main []
  (let 
    [addresses
      '("http://google.com"
        "http://amazon.com"
        "http://google.com/badurl")]
  (while true
    (doseq [address addresses]
      (println (available? address)))
    (Thread/sleep (* 1000 60)))))

$ cd pinger
$ lein uberjar

绝对路径
$ java -jar /vagrant/MyClojure/pinger/target/pinger-0.0.1-SNAPSHOT-standalone.jar

或

来自 project.clj 的相对路径
$ java -jar ./target/pinger-0.0.1-SNAPSHOT-standalone.jar

【讨论】：