布尔选项在命令行上由其存在表示.例如,如果存在选项,则其值为true,否则将其视为false.考虑以下示例,我们打印当前日期,如果存在-t标志,那么我们也将打印时间.
CLITester.java
import java.util.Calendar; import java.util.Date; import org.apache.commons.cli.CommandLine; import org.apache.commons.cli.CommandLineParser; import org.apache.commons.cli.DefaultParser; import org.apache.commons.cli.Options; import org.apache.commons.cli.ParseException; public class CLITester { public static void main(String[] args) throws ParseException { Options options = new Options(); options.addOption("t", false, "display time"); CommandLineParser parser = new DefaultParser(); CommandLine cmd = parser.parse( options, args); Calendar date = Calendar.getInstance(); int day = date.get(Calendar.DAY_OF_MONTH); int month = date.get(Calendar.MONTH); int year = date.get(Calendar.YEAR); int hour = date.get(Calendar.HOUR); int min = date.get(Calendar.MINUTE); int sec = date.get(Calendar.SECOND); System.out.print(day + "/" + month + "/" + year); if(cmd.hasOption("t")) { System.out.print(" " + hour + ":" + min + ":" + sec); } } }
运行文件而不通过任何选项并查看结果.
java CLITester 12/11/2017
运行文件时传递-t作为选项并查看结果.
java CLITester 12/11/2017 4:13:10