with-open

(with-open bindings & body)

在绑定了名字 name 与初始值 init 的 try 表达式里面对 body 进行求值 并按照绑定时间从晚到早的顺序 在 finally 语句里面对每个 name 执行 (.close name) 调用

(ns io
  (:require [clojure.java.io :as io]))

(defn readLineByLine [file-name]
  (with-open [reader (io/reader file-name)]
    (doseq [line (line-seq reader)]
      (println line))))

(defn copyLineByLine [source target]
  (with-open [reader (io/reader source)
              writer (io/writer target)]
    (io/copy reader writer)))

讨论

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