Clojure-JVM上的函数式编程语言(16)Web应用作者: R. Mark Volkmann-优快云博客

原帖地址：http://java.ociweb.com/mark/clojure/article.html#WebApps

作者：R. Mark Volkmann

译者：RoySong

Web应用

有多种Clojure库来创建Web应用。一个常见的选择是采用Compojure，可以从

http://github.com/weavejester/compojure/tree/master 获得。最新的版本可以从Git 资源库中获取到（假设

已经安装了Git）：

git clone git://github.com/weavejester/compojure.gitgit clone git://github.com/weavejester/compojure.git

上述命令会在当前目录下建立一个compojure目录，然后从 http://cloud.github.com/downloads/weavejester/compojure/deps.zip 下载所需的jar包，然后将deps.zip放置在 compojure目录下并将它的内容解压到 deps子目录中去。

要构建compojure.jar，在 compojure目录中运行 ant即可。

需要升级Compojure时，在compojure目录中运行以下命令：

git pull
ant clean deps jar

deps子目录下面的所有jar包都必须包含在classpath中，打成这个目的的一种方法是修改 clj脚本，然后用它来

运行web应用。在用来运行clojure.main的 java命令后加上"-cp $CP "，并且在设置CP之前加上以下的命令：

# Set CP to a path list that contains clojure.jar
# and possibly clojure-contrib.jar.
COMPOJURE_DIR=path-to-compojure-dir
COMPOJURE_JAR=$COMPOJURE_DIR/compojure.jar
CP=$CP:$COMPOJURE_JAR
for file in $COMPOJURE_DIR/deps/*.jar
do
  CP=$CP:$file
done

下面是一个简单的Compojure Web应用例子：

(ns com.ociweb.hello
  (:use compojure))

(def host "localhost")
(def port 8080)
(def in-path "/hello")
(def out-path "/hello-out")

(defn html-doc
  "generates well-formed HTML for a given title and body content"
  [title & body]
  (html
    (doctype :html4)
    [:html
      [:head [:title title]]
      [:body body]]))

; Creates HTML for input form.
(def hello-in
  (html-doc "Hello In"
    (form-to [:post out-path]
      "Name: "
      (text-field {:size 10} :name "World")
      [:br]
      (reset-button "Reset")
      (submit-button "Greet"))))

; Creates HTML for result message.
(defn hello-out [name]
  (html-doc "Hello Out"
    [:h1 "Hello, " name "!"]))

(defroutes hello-service
  ; The following three lines map HTTP methods
  ; and URL patterns to response HTML.
  (GET in-path hello-in)
  (POST out-path (hello-out (params :name)))
  (ANY "*" (page-not-found))) ; displays ./public/404.html by default

(println (str "browse http://" host ":" port in-path))
; -> browse http://localhost:8080/hello
(run-server {:port port} "/*" (servlet hello-service))