在Java中解析命令行参数的好方法是什么?
当前回答
看看这些:
http://commons.apache.org/cli/ http://www.martiansoftware.com/jsap/
或者自己卷:
http://docs.oracle.com/javase/7/docs/api/java/util/Scanner.html
例如,这是你如何使用common -cli来解析2个字符串参数:
import org.apache.commons.cli.*;
public class Main {
public static void main(String[] args) throws Exception {
Options options = new Options();
Option input = new Option("i", "input", true, "input file path");
input.setRequired(true);
options.addOption(input);
Option output = new Option("o", "output", true, "output file");
output.setRequired(true);
options.addOption(output);
CommandLineParser parser = new DefaultParser();
HelpFormatter formatter = new HelpFormatter();
CommandLine cmd = null;//not a good practice, it serves it purpose
try {
cmd = parser.parse(options, args);
} catch (ParseException e) {
System.out.println(e.getMessage());
formatter.printHelp("utility-name", options);
System.exit(1);
}
String inputFilePath = cmd.getOptionValue("input");
String outputFilePath = cmd.getOptionValue("output");
System.out.println(inputFilePath);
System.out.println(outputFilePath);
}
}
命令行用法:
$> java -jar target/my-utility.jar -i asd
Missing required option: o
usage: utility-name
-i,--input <arg> input file path
-o,--output <arg> output file
其他回答
看看Spring Shell
Spring Shell’s features include A simple, annotation driven, programming model to contribute custom commands Use of Spring Boot auto-configuration functionality as the basis for a command plugin strategy Tab completion, colorization, and script execution Customization of command prompt, shell history file name, handling of results and errors Dynamic enablement of commands based on domain specific criteria Integration with the bean validation API Already built-in commands, such as clear screen, gorgeous help, exit ASCII art Tables, with formatting, alignment, fancy borders, etc.
看一看最近的JCommander。
我创造了它。我很高兴收到问题或功能请求。
如果你熟悉gnu getopt,有一个Java端口:http://www.urbanophile.com/arenn/hacking/download.htm。
似乎有一些类是这样做的:
http://docs.sun.com/source/816-5618-10/netscape/ldap/util/GetOpt.html http://xml.apache.org/xalan-j/apidocs/org/apache/xalan/xsltc/cmdline/getopt/GetOpt.html
如果您已经在使用Spring Boot,那么参数解析将是现成的。
如果你想在启动后运行一些东西,实现ApplicationRunner接口:
@SpringBootApplication
public class Application implements ApplicationRunner {
public static void main(String[] args) {
SpringApplication.run(Application.class, args);
}
@Override
public void run(ApplicationArguments args) {
args.containsOption("my-flag-option"); // test if --my-flag-option was set
args.getOptionValues("my-option"); // returns values of --my-option=value1 --my-option=value2
args.getOptionNames(); // returns a list of all available options
// do something with your args
}
}
您的run方法将在上下文成功启动后被调用。
如果你需要在启动你的应用程序上下文之前访问参数,你可以简单地手动解析应用程序参数:
@SpringBootApplication
public class Application implements ApplicationRunner {
public static void main(String[] args) {
ApplicationArguments arguments = new DefaultApplicationArguments(args);
// do whatever you like with your arguments
// see above ...
SpringApplication.run(Application.class, args);
}
}
最后,如果您需要访问bean中的参数,只需注入ApplicationArguments:
@Component
public class MyBean {
@Autowired
private ApplicationArguments arguments;
// ...
}
正如前面提到的一个评论(https://github.com/pcj/google-options)是一个很好的开始。
我想补充的一点是:
1)如果您遇到一些解析器反射错误,请尝试使用更新版本的guava。在我的例子中:
maven_jar(
name = "com_google_guava_guava",
artifact = "com.google.guava:guava:19.0",
server = "maven2_server",
)
maven_jar(
name = "com_github_pcj_google_options",
artifact = "com.github.pcj:google-options:jar:1.0.0",
server = "maven2_server",
)
maven_server(
name = "maven2_server",
url = "http://central.maven.org/maven2/",
)
2)当运行命令行时:
bazel run path/to/your:project -- --var1 something --var2 something -v something
3)当你需要使用帮助时,只需输入:
bazel run path/to/your:project -- --help
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