Spring CommandLinePropertySource

  • Author: HuiFer

  • 源码阅读仓库: SourceHot-spring

  • 类全路径: org.springframework.core.env.CommandLinePropertySource

  • 作用: 用来存储命令行参数
  1. public abstract class CommandLinePropertySource<T> extends EnumerablePropertySource<T> {
  3.    public static final String COMMAND_LINE_PROPERTY_SOURCE_NAME = "commandLineArgs";
  5.    public static final String DEFAULT_NON_OPTION_ARGS_PROPERTY_NAME = "nonOptionArgs";
  8.    private String nonOptionArgsPropertyName = DEFAULT_NON_OPTION_ARGS_PROPERTY_NAME;
  12.    public CommandLinePropertySource(T source) {
  13.       // 命令行参数, 属性值
  14.       super(COMMAND_LINE_PROPERTY_SOURCE_NAME, source);
  15.    }
  17.    public CommandLinePropertySource(String name, T source) {
  18.       // 参数名称, 参数值
  19.       super(name, source);
  20.    }
  23.    public void setNonOptionArgsPropertyName(String nonOptionArgsPropertyName) {
  24.       this.nonOptionArgsPropertyName = nonOptionArgsPropertyName;
  25.    }
  27.    @Override
  28.    public final boolean containsProperty(String name) {
  29.       // 输入值是否等于nonOptionArgs
  30.       if (this.nonOptionArgsPropertyName.equals(name)) {
  31.          // 等于后判断参数列表是否为空
  32.          return !this.getNonOptionArgs().isEmpty();
  33.       }
  34.       // 是否存在 name 属性
  35.       return this.containsOption(name);
  36.    }
  38.    @Override
  39.    @Nullable
  40.    public final String getProperty(String name) {
  41.       if (this.nonOptionArgsPropertyName.equals(name)) {
  42.          // 获取 非可选项参数列表
  43.          Collection<String> nonOptionArguments = this.getNonOptionArgs();
  44.          if (nonOptionArguments.isEmpty()) {
  45.             return null;
  46.          }
  47.          else {
  48.             // 可选参数命令行参数
  49.             return StringUtils.collectionToCommaDelimitedString(nonOptionArguments);
  50.          }
  51.       }
  52.       Collection<String> optionValues = this.getOptionValues(name);
  53.       if (optionValues == null) {
  54.          return null;
  55.       }
  56.       else {
  57.          // 命令行参数
  58.          return StringUtils.collectionToCommaDelimitedString(optionValues);
  59.       }
  60.    }
  63.    /**
  64.     * 是否存在 name 的命令行参数
  65.     */
  66.    protected abstract boolean containsOption(String name);
  68.    /**
  69.     * 获取参数列表集合
  70.     */
  71.    @Nullable
  72.    protected abstract List<String> getOptionValues(String name);
  74.    /**
  75.     * 获取 non-option 参数列表
  76.     */
  77.    protected abstract List<String> getNonOptionArgs();
  79. }

getOptionValues

  1. /**
  2.  * Return the collection of values associated with the command line option having the
  3.  * given name.
  4.  * <ul>
  5.  * <li>if the option is present and has no argument (e.g.: "--foo"), return an empty
  6.  * collection ({@code []})</li>
  7.  * <li>if the option is present and has a single value (e.g. "--foo=bar"), return a
  8.  * collection having one element ({@code ["bar"]})</li>
  9.  * <li>if the option is present and the underlying command line parsing library
  10.  * supports multiple arguments (e.g. "--foo=bar --foo=baz"), return a collection
  11.  * having elements for each value ({@code ["bar", "baz"]})</li>
  12.  * <li>if the option is not present, return {@code null}</li>
  13.  * </ul>
  14.  *
  15.  * 获取参数列表集合
  16.  */
  17. @Nullable
  18. protected abstract List<String> getOptionValues(String name);

阅读注释可以知道该方法可以获取命令行参数的列表.

  • 如 --foo作为开头当输入命令行为 --foo=bar --foo=baz 在输入参数名称 foo 会得到数据bar,baz