- Picocli is a one-file framework for creating Java command line applications with almost zero code. - It supports a variety of command line syntax styles including POSIX, GNU, MS-DOS and more. - Generates highly customizable usage help messages with ANSI colors and styles. - Picocli-based applications can have command line TAB completion - showing available options, option parameters and subcommands, for any level of nested subcommands. + Picocli is a framework for creating Java command line applications with almost zero code.
- How it works: annotate your class and pass it to the CommandLine constructor.
- Then invoke CommandLine.parseArgs or CommandLine.execute with
- the command line parameters, and picocli parses the command line arguments and converts them
- to strongly typed values, which are then injected in the annotated fields and methods of your class.
+ Most application will only need the main picocli module, but
+ we recommend also configuring
+ the picocli-codegen module as an annotation processor for your project.
+ This provides compile-time error checking and
+ generates GraalVM
+ configuration files under
+ META-INF/native-image/picocli-generated/$project during compilation,
+ to be included in the application jar.
+ This in turn facilitates converting your command line application to a native image.
- Picocli provides an execute method
- that allows applications to omit error handling and other boilerplate code for common use cases.
- Here is a small example application that uses the CommandLine.execute method
- to do parsing and error handling in one line of code.
+ The picocli-groovy module allows
+ Groovy scripts to use picocli
+ annotations for even more compact code.
- The full user manual is hosted at https://picocli.info.
+ The picocli-shell-jline2 and picocli-shell-jline3 modules
+ are of interest to applications that want to provide an interactive shell-like console.
+
+ The picocli-spring-boot-starter module provides Spring integration.
+ Particularly, it allows for @Autowired or
+ @javax.inject-annotated program elements in picocli components
+ (commands, subcommands, type converters, default providers, etc.)
+ to be injected with values from Spring's Application Context.
-@Command(name = "checksum", mixinStandardHelpOptions = true, version = "Checksum 4.0",
- description = "Prints the checksum (SHA-1 by default) of a file to STDOUT.")
-class CheckSum implements Callable<Integer> {
-
- @Parameters(index = "0", description = "The file whose checksum to calculate.")
- private File file;
-
- @Option(names = {"-a", "--algorithm"}, description = "MD5, SHA-1, SHA-256, ...")
- private String algorithm = "SHA-1";
-
- @Override
- public Integer call() throws Exception { // your business logic goes here
- byte[] fileContents = Files.readAllBytes(file.toPath());
- byte[] digest = MessageDigest.getInstance(algorithm).digest(fileContents);
- System.out.printf("%0" + (digest.length*2) + "x%n", new BigInteger(1, digest));
- return 0;
- }
-
- // CheckSum implements Callable, so parsing, error handling and handling user
- // requests for usage help or version help can be done with one line of code.
- public static void main(String[] args) {
- int exitCode = new CommandLine(new CheckSum()).execute(args);
- System.exit(exitCode);
- }
-}
-
diff --git a/src/main/java9/module-info.java b/src/main/java9/module-info.java
index 1fc1f120a..5b5dc29bd 100644
--- a/src/main/java9/module-info.java
+++ b/src/main/java9/module-info.java
@@ -25,8 +25,55 @@
// select the 'java9' folder and click 'Mark as: Excluded'.
/**
- * Defines API and implementation for creating command line (CLI) applications.
+ * Defines API and implementation for parsing command line arguments and creating command line (CLI) applications.
+ * + * The parser supports a variety of command line syntax styles including POSIX, GNU, MS-DOS and more. + * Generates highly customizable usage help messages with ANSI colors and styles. + * Picocli-based applications can have command line TAB completion + * showing available options, option parameters and subcommands, for any level of nested subcommands. + *
+ *
+ * How it works: annotate your class and pass it to the CommandLine constructor.
+ * Then invoke CommandLine.parseArgs or CommandLine.execute with
+ * the command line parameters, and picocli parses the command line arguments and converts them
+ * to strongly typed values, which are then injected in the annotated fields and methods of your class.
+ *
+ * Picocli provides an execute method
+ * that allows applications to omit error handling and other boilerplate code for common use cases.
+ * Here is a small example application that uses the CommandLine.execute method
+ * to do parsing and error handling in one line of code.
+ *
+ * The full user manual is hosted at https://picocli.info. + *
+ *
+ * @Command(name = "checksum", mixinStandardHelpOptions = true, version = "Checksum 4.0",
+ * description = "Prints the checksum (SHA-1 by default) of a file to STDOUT.")
+ * class CheckSum implements Callable<Integer> {
*
+ * @Parameters(index = "0", description = "The file whose checksum to calculate.")
+ * private File file;
+ *
+ * @Option(names = {"-a", "--algorithm"}, description = "MD5, SHA-1, SHA-256, ...")
+ * private String algorithm = "SHA-1";
+ *
+ * @Override
+ * public Integer call() throws Exception { // your business logic goes here
+ * byte[] fileContents = Files.readAllBytes(file.toPath());
+ * byte[] digest = MessageDigest.getInstance(algorithm).digest(fileContents);
+ * System.out.printf("%0" + (digest.length*2) + "x%n", new BigInteger(1, digest));
+ * return 0;
+ * }
+ *
+ * // CheckSum implements Callable, so parsing, error handling and handling user
+ * // requests for usage help or version help can be done with one line of code.
+ * public static void main(String[] args) {
+ * int exitCode = new CommandLine(new CheckSum()).execute(args);
+ * System.exit(exitCode);
+ * }
+ * }
+ *
* @since 4.0.0
*/
module info.picocli {