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法律研究Java 9 中的 JShell？
JShell 是 Java 9 版本中引入的一個新概念。它提供了 Java 的REPL （Read-Eval-Print-Loop，讀取-求值-列印-迴圈）功能。使用 JShell，我們可以在不進行編譯的情況下測試基於 Java 的邏輯和表示式 。REPL 充當了一個即時反饋迴圈，並對此特定語言中的生產力產生了巨大影響。
步驟 1：開啟命令提示符並鍵入JShell。
Microsoft Windows [Version 6.3.9600] (c) 2013 Microsoft Corporation. All rights reserved. C:\Users\User>JShell | Welcome to JShell -- Version 9.0.4 | For an introduction type: /help intro jshell>
步驟 2：在 JShell 命令視窗中鍵入/help（檢視 JShell 命令），並在它開始執行後。使用此命令。
jshell> /help | Type a Java language expression, statement, or declaration. | Or type one of the following commands: | /list [|-all|-start] | list the source you have typed | /edit | edit a source entry referenced by name or id | /drop | delete a source entry referenced by name or id | /save [-all|-history|-start] | Save snippet source to a file. | /open | open a file as source input | /vars [|-all|-start] | list the declared variables and their values | /methods [|-all|-start] | list the declared methods and their signatures | /types [|-all|-start] | list the declared types | /imports | list the imported items | /exit | exit jshell | /env [-class-path ] [-module-path ] [-add-modules < | view or change the evaluation context | /reset [-class-path ] [-module-path ] [-add-modules | reset jshell | /reload [-restore] [-quiet] [-class-path ] [-module-path | reset and replay relevant history -- current or previous ( | /history | history of what you have typed | /help [|] | get information about jshell | /set editor|start|feedback|mode|prompt|truncation|format ... | set jshell configuration information | /? [|] | get information about jshell | /! | re-run last snippet | / | re-run snippet by id | /- | re-run n-th previous snippet | | For more information type '/help' followed by the name of a | command or a subject. | For example '/help /list' or '/help intro'. | | Subjects: | | intro | an introduction to the jshell tool | shortcuts | a description of keystrokes for snippet and command comple | information access, and automatic code generation | context | the evaluation context options for /env /reload and /reset
步驟 3：在 JShell 命令視窗中鍵入/imports來獲取 JShell 匯入的軟體包。
jshell> /imports | import java.io.* | import java.math.* | import java.net.* | import java.nio.file.* | import java.util.* | import java.util.concurrent.* | import java.util.function.* | import java.util.prefs.* | import java.util.regex.* | import java.util.stream.*
步驟 4：在 JShell 中執行計算（使用 JShell 嘗試算術計算）
jshell> 3+5 $1 ==> 8 jshell> 8-4 $2 ==> 4 jshell> 2*6 $3 ==> 12 jshell> 9%3 $4 ==> 0 jshell> 8/2 $5 ==> 4
步驟 5：要退出 JShell，請鍵入/exit。
jshell> /exit | Goodbye
更新於： 17-2-2020
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