The Java Tutorials have been written for JDK 8.Java教程是为JDK 8编写的。Examples and practices described in this page don't take advantage of improvements introduced in later releases and might use technology no longer available.本页中描述的示例和实践没有利用后续版本中引入的改进,并且可能使用不再可用的技术。See Java Language Changes for a summary of updated language features in Java SE 9 and subsequent releases.有关Java SE 9及其后续版本中更新的语言特性的摘要,请参阅Java语言更改。
See JDK Release Notes for information about new features, enhancements, and removed or deprecated options for all JDK releases.有关所有JDK版本的新功能、增强功能以及已删除或不推荐的选项的信息,请参阅JDK发行说明。
This section defines a reusable test harness, 本节定义了一个可重用的测试工具RegexTestHarness.java
, for exploring the regular expression constructs supported by this API. RegexTestHarness.java
,用于探索此API支持的正则表达式构造。The command to run this code is 运行此代码的命令是java RegexTestHarness
; no command-line arguments are accepted. java RegexTestHarness
;不接受任何命令行参数。The application loops repeatedly, prompting the user for a regular expression and input string. 应用程序重复循环,提示用户输入正则表达式和输入字符串。Using this test harness is optional, but you may find it convenient for exploring the test cases discussed in the following pages.使用此测试线束是可选的,但是您可能会发现探索以下页面中讨论的测试用例很方便。
import java.io.Console; import java.util.regex.Pattern; import java.util.regex.Matcher; public class RegexTestHarness { public static void main(String[] args){ Console console = System.console(); if (console == null) { System.err.println("No console."); System.exit(1); } while (true) { Pattern pattern = Pattern.compile(console.readLine("%nEnter your regex: ")); Matcher matcher = pattern.matcher(console.readLine("Enter input string to search: ")); boolean found = false; while (matcher.find()) { console.format("I found the text" + " \"%s\" starting at " + "index %d and ending at index %d.%n", matcher.group(), matcher.start(), matcher.end()); found = true; } if(!found){ console.format("No match found.%n"); } } } }
Before continuing to the next section, save and compile this code to ensure that your development environment supports the required packages.在继续下一节之前,请保存并编译此代码,以确保您的开发环境支持所需的包。