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  1. import java.util.HashMap;
  2. import java.util.function.Function;
  3. import java.math.*;
  4. import java.time.*;
  5.  
  6. class Ideone {
  7.  
  8. 	@SuppressWarnings({ "rawtypes", "unchecked" })
  9. 	private static Object parse(String argString, Class param) {
  10. 		Function<String,?> func = parser.get(param);
  11. 		if (func != null)
  12. 			return func.apply(argString);
  13. 		if (param.isEnum())
  14. 			return Enum.valueOf(param, argString);
  15. 		throw new UnsupportedOperationException("Cannot parse string to " + param.getName());
  16. 	}
  17.  
  18. 	private static HashMap<Class<?>, Function<String,?>> parser = new HashMap<>();
  19. 	static {
  20. 		parser.put(boolean.class       , Boolean::parseBoolean);
  21. 		parser.put(byte.class          , Byte::parseByte);
  22. 		parser.put(short.class         , Short::parseShort);
  23. 		parser.put(int.class           , Integer::parseInt);
  24. 		parser.put(long.class          , Long::parseLong);
  25. 		parser.put(double.class        , Double::parseDouble);
  26. 		parser.put(float.class         , Float::parseFloat);
  27. 		parser.put(Boolean.class       , Boolean::valueOf);
  28. 		parser.put(Byte.class          , Byte::valueOf);
  29. 		parser.put(Short.class         , Short::valueOf);
  30. 		parser.put(Integer.class       , Integer::valueOf);
  31. 		parser.put(Long.class          , Long::valueOf);
  32. 		parser.put(Double.class        , Double::valueOf);
  33. 		parser.put(Float.class         , Float::valueOf);
  34. 		parser.put(String.class        , String::valueOf);
  35. 		parser.put(BigDecimal.class    , BigDecimal::new);
  36. 		parser.put(BigInteger.class    , BigInteger::new);
  37. 		parser.put(LocalDate.class     , LocalDate::parse);
  38. 		parser.put(LocalDateTime.class , LocalDateTime::parse);
  39. 		parser.put(LocalTime.class     , LocalTime::parse);
  40. 		parser.put(MonthDay.class      , MonthDay::parse);
  41. 		parser.put(OffsetDateTime.class, OffsetDateTime::parse);
  42. 		parser.put(OffsetTime.class    , OffsetTime::parse);
  43. 		parser.put(Year.class          , Year::parse);
  44. 		parser.put(YearMonth.class     , YearMonth::parse);
  45. 		parser.put(ZonedDateTime.class , ZonedDateTime::parse);
  46. 		parser.put(ZoneId.class        , ZoneId::of);
  47. 		parser.put(ZoneOffset.class    , ZoneOffset::of);
  48. 	}
  49.  
  50. 	public static void main(String[] args) {
  51. 		test("true", boolean.class);
  52. 		test("123" , byte.class);
  53. 		test("123" , short.class);
  54. 		test("123" , int.class);
  55. 		test("123" , long.class);
  56. 		test("123" , double.class);
  57. 		test("123" , float.class);
  58. 		test("true", Boolean.class);
  59. 		test("123" , Byte.class);
  60. 		test("123" , Short.class);
  61. 		test("123" , Integer.class);
  62. 		test("123" , Long.class);
  63. 		test("123" , Double.class);
  64. 		test("123" , Float.class);
  65. 		test("123" , BigDecimal.class);
  66. 		test("123" , BigInteger.class);
  67. 		test("Hello World", String.class);       // String
  68. 		test("HALF_EVEN"  , RoundingMode.class); // enum
  69. 		test("2016"                                       , Year.class);
  70. 		test("2016-04"                                    , YearMonth.class);
  71. 		test("--04-01"                                    , MonthDay.class);
  72. 		test("2016-04-01"                                 , LocalDate.class);
  73. 		test("23:18:47"                                   , LocalTime.class);
  74. 		test("23:18:47-04:00"                             , OffsetTime.class);
  75. 		test("2016-04-01T23:18:47"                        , LocalDateTime.class);
  76. 		test("2016-04-01T23:18:47-04:00"                  , OffsetDateTime.class);
  77. 		test("2016-04-01T23:18:47-04:00[America/New_York]", ZonedDateTime.class);
  78. 		test("America/New_York"                           , ZoneId.class);
  79. 		test("-04:00"                                     , ZoneOffset.class);
  80. 		test("FRIDAY"                                     , DayOfWeek.class);     // enum
  81. 		test("APRIL"                                      , Month.class);         // enum
  82. 	}
  83.  
  84. 	private static void test(String argString, Class<?> param) {
  85. 		Object ret = parse(argString, param);
  86. 		System.out.printf("%-21s -> %-19s   [%-22s -> %s]%n",
  87. 		                  '"' + argString + '"', ret, param.getName(), ret.getClass().getName());
  88. 	}
  89.  
  90. }
Success #stdin #stdout 0.37s 321408KB
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"true"                -> true                  [boolean                -> java.lang.Boolean]
"123"                 -> 123                   [byte                   -> java.lang.Byte]
"123"                 -> 123                   [short                  -> java.lang.Short]
"123"                 -> 123                   [int                    -> java.lang.Integer]
"123"                 -> 123                   [long                   -> java.lang.Long]
"123"                 -> 123.0                 [double                 -> java.lang.Double]
"123"                 -> 123.0                 [float                  -> java.lang.Float]
"true"                -> true                  [java.lang.Boolean      -> java.lang.Boolean]
"123"                 -> 123                   [java.lang.Byte         -> java.lang.Byte]
"123"                 -> 123                   [java.lang.Short        -> java.lang.Short]
"123"                 -> 123                   [java.lang.Integer      -> java.lang.Integer]
"123"                 -> 123                   [java.lang.Long         -> java.lang.Long]
"123"                 -> 123.0                 [java.lang.Double       -> java.lang.Double]
"123"                 -> 123.0                 [java.lang.Float        -> java.lang.Float]
"123"                 -> 123                   [java.math.BigDecimal   -> java.math.BigDecimal]
"123"                 -> 123                   [java.math.BigInteger   -> java.math.BigInteger]
"Hello World"         -> Hello World           [java.lang.String       -> java.lang.String]
"HALF_EVEN"           -> HALF_EVEN             [java.math.RoundingMode -> java.math.RoundingMode]
"2016"                -> 2016                  [java.time.Year         -> java.time.Year]
"2016-04"             -> 2016-04               [java.time.YearMonth    -> java.time.YearMonth]
"--04-01"             -> --04-01               [java.time.MonthDay     -> java.time.MonthDay]
"2016-04-01"          -> 2016-04-01            [java.time.LocalDate    -> java.time.LocalDate]
"23:18:47"            -> 23:18:47              [java.time.LocalTime    -> java.time.LocalTime]
"23:18:47-04:00"      -> 23:18:47-04:00        [java.time.OffsetTime   -> java.time.OffsetTime]
"2016-04-01T23:18:47" -> 2016-04-01T23:18:47   [java.time.LocalDateTime -> java.time.LocalDateTime]
"2016-04-01T23:18:47-04:00" -> 2016-04-01T23:18:47-04:00   [java.time.OffsetDateTime -> java.time.OffsetDateTime]
"2016-04-01T23:18:47-04:00[America/New_York]" -> 2016-04-01T23:18:47-04:00[America/New_York]   [java.time.ZonedDateTime -> java.time.ZonedDateTime]
"America/New_York"    -> America/New_York      [java.time.ZoneId       -> java.time.ZoneRegion]
"-04:00"              -> -04:00                [java.time.ZoneOffset   -> java.time.ZoneOffset]
"FRIDAY"              -> FRIDAY                [java.time.DayOfWeek    -> java.time.DayOfWeek]
"APRIL"               -> APRIL                 [java.time.Month        -> java.time.Month]
https://ideone.com/WtNDN2
language:
Java (HotSpot 12)
created:
9 years ago
visibility:
public

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