带有Apache Commons CLI的两个独家选项组

Question

我正在构建一个命令行Java应用程序，在使用Apache Commons CLI解析命令行参数时遇到问题。

我试图讲述我的场景，其中我需要有两个独占的命令行参数组，分别具有长（-abc）和短（-a）参数。

用例1

• 短params：-d oracle-j jdbc： oracle：薄：@//host： port/数据库
• 相同，但与长params：-方言oracle-jdbcUrl jdbc： oracle：薄：@//host： port/数据库

用例2：

• 短参数：-d oracle-h host-p 1521-s database-U user-p pwd
• 相同但有长参数：-方言oracle-主机主机主机-端口1521-sid数据库-用户-密码pwd

因此，我创建了两个带有适当的选项的选项组：

OptionGroup jdbcUrlGroup = new OptionGroup();
jdbcUrlGroup.setRequired(true);
jdbcUrlGroup.addOption(jdbcUrl);

第二组：

OptionGroup customConfigurationGroup = new OptionGroup();
customConfigurationGroup.setRequired(true);
customConfigurationGroup.addOption(host);
customConfigurationGroup.addOption(port);
customConfigurationGroup.addOption(sid);
customConfigurationGroup.addOption(user);
customConfigurationGroup.addOption(password);

然后我用这种方式构建选项对象：

Options options = new Options();
options.addOptionGroup(jdbcUrlGroup);
options.addOptionGroup(customConfigurationGroup);
options.addOption(dialect);

但这并不起作用，因为它期望定义这两个组。

方言选项是这样定义的：

Option dialect = Option
        .builder("d")
        .longOpt("dialect")
        .required(false)
        .hasArg()
        .argName("DIALECT")
        .desc("supported SQL dialects: oracle. Default value: oracle")
        .build();

除了这个属性之外，其他强制Option定义看起来类似：

.required(true)

结果：

• -d oracle：缺少必需的选项：[-j…]，[-h…，-p…，-s…，-U…，-p…]
• -d oracle-jdbcUrl xxx：缺少必需的选项：[-h…，-p…，-s…，-U…，-p…]
• -d oracle-h yyy：缺少必需的选项：[-j…]

但是我想要的是以下内容：如果提供了JDBC URL，那么就不需要主机、端口等参数，或者相反。




Answer 1

我认为是时候忘记Apache Commons CLI并将其标记为不推荐使用的库了。好的，如果您只有几个命令行参数，那么您可以使用它，否则最好不要使用。事实上，这个Apache项目最近（2019年2月17日）进行了更新，但仍然缺少许多功能，使用Apache Commons CLI库有点痛苦。

picocli项目看起来更适合解析命令行参数。这是一个非常直观的库，易于使用，并有一个很好的和全面的文档。我认为，一个拥有完美文档的中档工具比一个没有任何文档的闪亮项目要好。

无论如何picocli是一个非常好的库与完美的留档，所以我给双加加到它：）

这就是我如何用picocli覆盖我的用例：

import picocli.CommandLine;
import picocli.CommandLine.ArgGroup;
import picocli.CommandLine.Command;
import picocli.CommandLine.Option;
import picocli.CommandLine.Parameters;

@Command(name = "SqlRunner",
        sortOptions = false,
        usageHelpWidth = 100,
        description = "SQL command line tool. It executes the given SQL and show the result on the standard output.\n",
        parameterListHeading = "General options:\n",
        footerHeading = "\nPlease report issues at [e-mail].",
        footer = "\nDocumentation, source code: https://github.com/zappee/sql-runner.git")
public class SqlRunner implements Runnable {

    /**
     * Definition of the general command line options.
     */
    @Option(names = {"-?", "--help"}, usageHelp = true, description = "Display this help and exit.")
    private boolean help;

    @Option(names = {"-d", "--dialect"}, defaultValue = "oracle", showDefaultValue = CommandLine.Help.Visibility.ALWAYS, description = "Supported SQL dialects: oracle.")
    private static String dialect;

    @ArgGroup(exclusive = true, multiplicity = "1", heading = "\nProvide a JDBC URL:\n")
    MainArgGroup mainArgGroup;

    /**
     * Two exclusive parameter groups:
     *    (1) JDBC URL parameter
     *    (2) Custom connection parameters
     */
    static class MainArgGroup {
        /**
         * JDBC URL option (only one parameter).
         */
        @Option(names = {"-j", "--jdbcUrl"}, arity = "1", description = "JDBC URL, example: jdbc:oracle:<drivertype>:@//<host>:<port>/<database>.")
        private static String jdbcUrl;

        /**
         * Custom connection parameter group.
         */
        @ArgGroup(exclusive = false, multiplicity = "1", heading = "\nCustom configuration:\n")
        CustomConfigurationGroup customConfigurationGroup;
    }

    /**
     * Definition of the SQL which will be executed.
     */
    @Parameters(index = "0", arity = "1", description = "SQL to be executed. Example: 'select 1 from dual'")
    String sql;

    /**
     * Custom connection parameters.
     */
    static class CustomConfigurationGroup {
        @Option(names = {"-h", "--host"}, required = true, description = "Name of the database server.")
        private static String host;

        @Option(names = {"-p", "--port"}, required = true, description = "Number of the port where the server listens for requests.")
        private static String port;

        @Option(names = {"-s", "--sid"}, required = true, description = "Name of the particular database on the server. Also known as the SID in Oracle terminology.")
        private static String sid;

        @Option(names = {"-U", "--user"}, required = true, description = "Name for the login.")
        private static String user;

        @Option(names = {"-P", "--password"}, required = true, description = "Password for the connecting user.")
        private static String password;
    }

    /**
     * The entry point of the executable JAR.
     *
     * @param args command line parameters
     */
    public static void main(String[] args) {
        CommandLine cmd = new CommandLine(new SqlRunner());
        int exitCode = cmd.execute(args);
        System.exit(exitCode);
    }

    /**
     * It is used to create a thread.
     */
    @Override
    public void run() {
        int exitCode = 0; //executeMyStaff();
        System.exit(exitCode);
    }
}

生成的帮助是这样的：

$ java -jar target/sql-runner-1.0-shaded.jar --help
Usage: SqlRunner [-?] [-d=<dialect>] (-j=<jdbcUrl> | (-h=<host> -p=<port> -s=<sid> -U=<user>
                 -P=<password>)) <sql>
SQL command line tool. It executes the given SQL and show the result on the standard output.

General settings:
      <sql>                 SQL to be executed. Example: 'select 1 from dual'
  -?, --help                Display this help and exit.
  -d, --dialect=<dialect>   Supported SQL dialects: oracle.
                              Default: oracle

Custom configuration:
  -h, --host=<host>         Name of the database server.
  -p, --port=<port>         Number of the port where the server listens for requests.
  -s, --sid=<sid>           Name of the particular database on the server. Also known as the SID in
                              Oracle terminology.
  -U, --user=<user>         Name for the login.
  -P, --password=<password> Password for the connecting user.

Provide a JDBC URL:
  -j, --jdbcUrl=<jdbcUrl>   JDBC URL, example: jdbc:oracle:<drivertype>:@//<host>:<port>/<database>.

Please report issues at [e-mail].
Documentation, source code: https://github.com/zappee/sql-runner.git

这种外观比Apache CLI生成的帮助要好得多。