这篇教程Java 9 REPL (JShell)写得很实用,希望能帮到您。 REPL(Read Eval Print Loop)意为交互式的编程环境。 JShell 是 Java 9 新增的一个交互式的编程环境工具。它允许你无需使用类或者方法包装来执行 Java 语句。它与 Python 的解释器类似,可以直接 输入表达式并查看其执行结果。 执行 JSHELL $ jshell| Welcome to JShell -- Version 9-ea| For an introduction type: /help introjshell> 查看 JShell 命令 输入 /help 可以查看 JShell相关的命令: jshell> /help| Type a Java language expression, statement, or declaration.| Or type one of the following commands:| /list [<name or id>|-all|-start]| list the source you have typed| /edit <name or id>| edit a source entry referenced by name or id| /drop <name or id>| delete a source entry referenced by name or id| /save [-all|-history|-start] <file>| Save snippet source to a file.| /open <file>| open a file as source input| /vars [<name or id>|-all|-start]| list the declared variables and their values| /methods [<name or id>|-all|-start]| list the declared methods and their signatures| /types [<name or id>|-all|-start]| list the declared types| /imports | list the imported items 执行 JShell 命令 /imports 命令用于查看已导入的包:
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.*jshell> JShell 执行计算 以下实例执行 JShell 简单计算: jshell> 3+1$1 ==> 4jshell> 13%7$2 ==> 6jshell> $2$2 ==> 6jshell> JShell 创建与使用函数 创建一个函数 doubled() ,将传入的整型参数乘于 2 后返回: jshell> int doubled(int i){ return i*2;}| created method doubled(int)jshell> doubled(6)$3 ==> 12jshell> 退出 JShell 输入 /exit 命令退出 jshell: jshell> /exit| Goodbye Java 9 模块系统 Java 9 改进 Javadoc |