{"id":6411,"date":"2026-05-06T14:02:21","date_gmt":"2026-05-06T05:02:21","guid":{"rendered":"https:\/\/route-zero.com\/recruit\/?post_type=route&p=6411"},"modified":"2026-10-06T14:02:29","modified_gmt":"2026-10-06T05:02:29","slug":"java-bigdecimal-equals-compareto-scale","status":"publish","type":"route","link":"https:\/\/route-zero.com\/recruit\/route\/6411\/","title":{"rendered":"BigDecimal equals\u3068compareTo\u306e\u9055\u3044\uff5c0.0\u30680.00\u3092\u6bd4\u8f03"},"content":{"rendered":"

`new BigDecimal("0.0").equals(new BigDecimal("0.00"))` \u304c`false`\u306b\u306a\u308b\u306e\u306f\u3001`BigDecimal.equals()`\u304c\u6570\u5024\u3060\u3051\u3067\u306a\u304f`scale`\u307e\u3067\u6bd4\u8f03\u3059\u308b\u305f\u3081\u3067\u3059\u3002\u6570\u5024\u3068\u3057\u3066\u540c\u3058\u304b\u3092\u5224\u5b9a\u3057\u305f\u3044\u306a\u3089`compareTo()`\u3092\u4f7f\u3044\u3001`a.compareTo(b) == 0`\u3067\u78ba\u8a8d\u3057\u307e\u3059\u3002\u9006\u306b\u3001`1.0`\u3068`1.00`\u306e\u8868\u73fe\u5dee\u305d\u306e\u3082\u306e\u306b\u610f\u5473\u304c\u3042\u308b\u5834\u5408\u306f`equals()`\u304c\u9069\u3057\u3066\u3044\u307e\u3059\u3002<\/p>\n

\u307e\u305a\u7d50\u8ad6\uff1a\u6570\u5024\u6bd4\u8f03\u306fcompareTo\u3001\u8868\u73fe\u4e00\u81f4\u306fequals<\/h2>\n\n\n\n\n\n\n\n
\u6bd4\u8f03\u65b9\u6cd5<\/th>\n0.0 \u3068 0.00<\/th>\n\u6bd4\u8f03\u3059\u308b\u3082\u306e<\/th>\n\u4e3b\u306a\u7528\u9014<\/th>\n<\/tr>\n<\/thead>\n
equals()<\/td>\nfalse<\/td>\n\u6570\u5024 + scale<\/td>\n\u8868\u73fe\u307e\u3067\u540c\u4e00\u304b\u78ba\u8a8d\u3059\u308b<\/td>\n<\/tr>\n
compareTo() == 0<\/td>\ntrue<\/td>\n\u6570\u5024<\/td>\n\u91d1\u984d\u30fb\u6570\u91cf\u306a\u3069\u6570\u5024\u3068\u3057\u3066\u540c\u3058\u304b\u78ba\u8a8d\u3059\u308b<\/td>\n<\/tr>\n
==<\/td>\n\u901a\u5e38false<\/td>\n\u53c2\u7167\u5148<\/td>\n\u540c\u3058\u30a4\u30f3\u30b9\u30bf\u30f3\u30b9\u304b\u78ba\u8a8d\u3059\u308b<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

Oracle\u306eBigDecimal API\u3067\u306f\u3001`compareTo()`\u306f2.0\u30682.00\u306e\u3088\u3046\u306b\u6570\u5024\u304c\u540c\u3058\u3067scale\u304c\u7570\u306a\u308b\u5024\u3092\u7b49\u3057\u3044\u3068\u307f\u306a\u3057\u307e\u3059\u3002\u4e00\u65b9\u3001`equals()`\u306f\u6570\u5024\u3068scale\u306e\u4e21\u65b9\u304c\u540c\u3058\u5834\u5408\u3060\u3051`true`\u306b\u306a\u308a\u307e\u3059\u3002<\/p>\n

\n

\u306a\u305c0.0\u30680.00\u306fequals\u3067\u4e00\u81f4\u3057\u306a\u3044\u306e\u304b<\/h2>\n

`BigDecimal`\u306f\u300110\u9032\u6570\u306e\u5024\u3060\u3051\u3067\u306a\u304fscale\u3082\u4fdd\u6301\u3057\u307e\u3059\u3002scale\u306f\u5c0f\u6570\u70b9\u4ee5\u4e0b\u306e\u6841\u6570\u306b\u95a2\u308f\u308b\u60c5\u5831\u3067\u3001`0.0`\u306fscale 1\u3001`0.00`\u306fscale 2\u3067\u3059\u3002\u305d\u306e\u305f\u3081\u6570\u5024\u3068\u3057\u3066\u306f\u540c\u30580\u3067\u3082\u3001`equals()`\u3067\u306f\u5225\u306e\u8868\u73fe\u3068\u3057\u3066\u6271\u308f\u308c\u307e\u3059\u3002<\/p>\n

import java.math.BigDecimal;\r\n\r\nBigDecimal a = new BigDecimal("0.0");\r\nBigDecimal b = new BigDecimal("0.00");\r\n\r\nSystem.out.println(a.scale());      \/\/ 1\r\nSystem.out.println(b.scale());      \/\/ 2\r\nSystem.out.println(a.equals(b));    \/\/ false<\/code><\/pre>\n
\n
\u7528\u8a9e\u89e3\u8aac\uff1ascale<\/strong>
BigDecimal\u304c\u4fdd\u6301\u3059\u308b\u5c0f\u6570\u70b9\u4ee5\u4e0b\u306e\u6841\u6570\u306b\u95a2\u3059\u308b\u60c5\u5831\u3067\u3059\u3002\u6570\u5024\u304c\u540c\u3058\u3067\u3082scale\u304c\u9055\u3048\u3070equals()\u306ffalse\u306b\u306a\u308a\u307e\u3059\u3002<\/p>\n<\/blockquote>\n
\n
\u91d1\u984d\u3084\u6570\u91cf\u3092\u6570\u5024\u3068\u3057\u3066\u6bd4\u3079\u308b\u306a\u3089compareTo\u3092\u4f7f\u3046<\/h2>\n
\u300c100.0\u5186\u300d\u3068\u300c100.00\u5186\u300d\u3092\u540c\u984d\u3068\u3057\u3066\u6271\u3044\u305f\u3044\u3088\u3046\u306a\u6570\u5024\u6bd4\u8f03\u3067\u306f\u3001`compareTo()`\u304c\u610f\u56f3\u306b\u5408\u3044\u307e\u3059\u3002\u623b\u308a\u5024\u304c0\u306a\u3089\u6570\u5024\u3068\u3057\u3066\u7b49\u3057\u3044\u305f\u3081\u3001scale\u306e\u9055\u3044\u3092\u6c17\u306b\u305b\u305a\u5224\u5b9a\u3067\u304d\u307e\u3059\u3002<\/p>\n
BigDecimal priceA = new BigDecimal("100.0");\r\nBigDecimal priceB = new BigDecimal("100.00");\r\n\r\nboolean sameAmount = priceA.compareTo(priceB) == 0;\r\nSystem.out.println(sameAmount); \/\/ true<\/code><\/pre>\n\n\n\n\n\n\n\n\n\n
\u5224\u5b9a<\/th>\n\u66f8\u304d\u65b9<\/th>\n<\/tr>\n<\/thead>\n
\u7b49\u3057\u3044<\/td>\na.compareTo(b) == 0<\/td>\n<\/tr>\n
a < b<\/td>\na.compareTo(b) < 0<\/td>\n<\/tr>\n
a > b<\/td>\na.compareTo(b) > 0<\/td>\n<\/tr>\n
a <= b<\/td>\na.compareTo(b) <= 0<\/td>\n<\/tr>\n
a >= b<\/td>\na.compareTo(b) >= 0<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n
\u5b9f\u88c5\u3067\u306f`-1`\u3084`1`\u3068\u306e\u5b8c\u5168\u4e00\u81f4\u3088\u308a\u30010\u3088\u308a\u5c0f\u3055\u3044\u30fb\u5927\u304d\u3044\u3068\u3044\u3046\u5f62\u3067\u66f8\u304f\u3068\u6bd4\u8f03\u306e\u610f\u56f3\u304c\u8aad\u307f\u53d6\u308a\u3084\u3059\u304f\u306a\u308a\u307e\u3059\u3002<\/p>\n
\n
equals\u3092\u4f7f\u3046\u3079\u304d\u5834\u9762\u3082\u3042\u308b<\/h2>\n
`equals()`\u304c\u9593\u9055\u3063\u3066\u3044\u308b\u308f\u3051\u3067\u306f\u3042\u308a\u307e\u305b\u3093\u3002\u6570\u5024\u3060\u3051\u3067\u306a\u304f\u5c0f\u6570\u6841\u306e\u8868\u73fe\u307e\u3067\u540c\u3058\u3067\u3042\u308b\u3053\u3068\u304c\u8981\u4ef6\u306a\u3089\u3001`equals()`\u304c\u9069\u5207\u3067\u3059\u3002\u305f\u3068\u3048\u3070\u3001\u5916\u90e8\u4ed5\u69d8\u3067scale\u3092\u542b\u3080\u8868\u73fe\u3092\u533a\u5225\u3059\u308b\u5834\u5408\u3084\u3001\u30c6\u30b9\u30c8\u3067\u6b63\u898f\u5316\u524d\u5f8c\u306e\u8868\u73fe\u307e\u3067\u78ba\u8a8d\u3057\u305f\u3044\u5834\u5408\u3067\u3059\u3002<\/p>\n
BigDecimal expected = new BigDecimal("12.00");\r\nBigDecimal actual   = new BigDecimal("12.00");\r\n\r\nSystem.out.println(expected.equals(actual)); \/\/ true<\/code><\/pre>\n
\u8981\u4ef6\u304c\u300c\u540c\u984d\u304b\u300d\u306a\u306e\u304b\u300c\u540c\u3058\u8868\u73fe\u304b\u300d\u306a\u306e\u304b\u3092\u5148\u306b\u6c7a\u3081\u308b\u3068\u3001`compareTo()`\u3068`equals()`\u3092\u9078\u3073\u3084\u3059\u304f\u306a\u308a\u307e\u3059\u3002<\/p>\n
HashMap\u30fbHashSet\u3067\u306fscale\u5dee\u306b\u3082\u6ce8\u610f\u3059\u308b<\/h2>\n
BigDecimal\u306e`hashCode()`\u3082scale\u306e\u5f71\u97ff\u3092\u53d7\u3051\u307e\u3059\u3002Oracle API\u3067\u306f\u3001\u6570\u5024\u304c\u540c\u3058\u3067\u3082scale\u304c\u7570\u306a\u308bBigDecimal\u306f\u901a\u5e38\u540c\u3058hash code\u306b\u306a\u3089\u306a\u3044\u3068\u8aac\u660e\u3055\u308c\u3066\u3044\u307e\u3059\u3002\u305d\u306e\u305f\u3081\u3001`HashSet`\u3084`HashMap`\u3067\u30ad\u30fc\u3068\u3057\u3066\u6271\u3046\u3068\u304d\u306f\u3001\u6570\u5024\u6bd4\u8f03\u3060\u3051\u3092\u671f\u5f85\u3057\u3066\u3044\u308b\u8a2d\u8a08\u3068\u305a\u308c\u306a\u3044\u304b\u78ba\u8a8d\u304c\u5fc5\u8981\u3067\u3059\u3002<\/p>\n
import java.math.BigDecimal;\r\nimport java.util.HashSet;\r\nimport java.util.Set;\r\n\r\nSet<BigDecimal> values = new HashSet<>();\r\nvalues.add(new BigDecimal("1.0"));\r\nvalues.add(new BigDecimal("1.00"));\r\n\r\nSystem.out.println(values.size()); \/\/ 2<\/code><\/pre>\n
\u300c\u6570\u5024\u304c\u540c\u3058\u306a\u3089\u540c\u3058\u30ad\u30fc\u3068\u3057\u3066\u6271\u3044\u305f\u3044\u300d\u3068\u3044\u3046\u8981\u4ef6\u3067\u306f\u3001\u4fdd\u5b58\u524d\u306bscale\u3092\u7d71\u4e00\u3059\u308b\u3001\u307e\u305f\u306f\u30c9\u30e1\u30a4\u30f3\u5074\u3067\u6bd4\u8f03\u898f\u5247\u3092\u6c7a\u3081\u308b\u306a\u3069\u3001\u30b3\u30ec\u30af\u30b7\u30e7\u30f3\u3078\u5165\u308c\u308b\u524d\u306e\u8a2d\u8a08\u304c\u91cd\u8981\u3067\u3059\u3002<\/p>\n
stripTrailingZeros\u3067\u6b63\u898f\u5316\u3059\u308b\u5834\u5408\u306e\u6ce8\u610f\u70b9<\/h2>\n
`stripTrailingZeros()`\u306f\u672b\u5c3e\u306e0\u3092\u53d6\u308a\u9664\u304d\u3001\u6570\u5024\u7684\u306b\u7b49\u3057\u3044BigDecimal\u3092\u8fd4\u3057\u307e\u3059\u3002\u30bc\u30ed\u306f`BigDecimal.ZERO`\u306b\u306a\u308a\u307e\u3059\u3002\u305f\u3060\u3057\u3001600.0\u304c`6E+2`\u76f8\u5f53\u306e\u8868\u73fe\u306b\u306a\u308b\u3088\u3046\u306bscale\u304c\u8ca0\u306b\u306a\u308b\u5834\u5408\u3082\u3042\u308b\u305f\u3081\u3001\u8868\u793a\u5f62\u5f0f\u307e\u3067\u4e00\u5b9a\u306b\u306a\u308b\u3068\u306f\u9650\u308a\u307e\u305b\u3093\u3002<\/p>\n
BigDecimal a = new BigDecimal("1.0").stripTrailingZeros();\r\nBigDecimal b = new BigDecimal("1.00").stripTrailingZeros();\r\n\r\nSystem.out.println(a.equals(b)); \/\/ true<\/code><\/pre>\n
\u5358\u306b\u6570\u5024\u3068\u3057\u3066\u7b49\u3057\u3044\u304b\u3092\u77e5\u308a\u305f\u3044\u3060\u3051\u306a\u3089\u3001\u6b63\u898f\u5316\u3057\u3066\u304b\u3089`equals()`\u3059\u308b\u3088\u308a`compareTo() == 0`\u306e\u65b9\u304c\u610f\u56f3\u3092\u76f4\u63a5\u8868\u305b\u307e\u3059\u3002`stripTrailingZeros()`\u306f\u4fdd\u5b58\u5f62\u5f0f\u3084\u6b63\u898f\u5316\u30eb\u30fc\u30eb\u3092\u305d\u308d\u3048\u305f\u3044\u5834\u5408\u306b\u691c\u8a0e\u3057\u307e\u3059\u3002<\/p>\n
\u5b9f\u52d9\u3067\u306f\u300c\u6bd4\u8f03\u3057\u305f\u3044\u610f\u5473\u300d\u3092\u5148\u306b\u6c7a\u3081\u308b<\/h2>\n
    \n
  • \u91d1\u984d\u30fb\u6570\u91cf\u3068\u3057\u3066\u540c\u3058\u304b\u3092\u5224\u5b9a\u3059\u308b \u2192 compareTo() == 0<\/li>\n
  • \u5927\u5c0f\u95a2\u4fc2\u3092\u5224\u5b9a\u3059\u308b \u2192 compareTo()\u30920\u3068\u6bd4\u8f03<\/li>\n
  • \u6570\u5024\u3068scale\u306e\u4e21\u65b9\u3092\u4e00\u81f4\u3055\u305b\u305f\u3044 \u2192 equals()<\/li>\n
  • HashMap\u30fbHashSet\u306e\u30ad\u30fc\u306b\u4f7f\u3046 \u2192 equals\/hashCode\u304cscale\u3092\u898b\u308b\u3053\u3068\u3092\u78ba\u8a8d<\/li>\n
  • \u672b\u5c3e0\u3092\u9664\u3044\u305f\u8868\u73fe\u3078\u6b63\u898f\u5316\u3057\u305f\u3044 \u2192 stripTrailingZeros()\u306escale\u5909\u5316\u3082\u78ba\u8a8d<\/li>\n<\/ul>\n
    `0.0`\u3068`0.00`\u304c\u540c\u3058\u304b\u3069\u3046\u304b\u306f\u3001Java\u306e\u90fd\u5408\u3060\u3051\u3067\u306f\u306a\u304f\u3001\u30a2\u30d7\u30ea\u30b1\u30fc\u30b7\u30e7\u30f3\u304c\u4f55\u3092\u300c\u540c\u3058\u300d\u3068\u5b9a\u7fa9\u3059\u308b\u304b\u3067\u6c7a\u307e\u308a\u307e\u3059\u3002\u6bd4\u8f03\u65b9\u6cd5\u3092\u9078\u3076\u524d\u306b\u3001\u6570\u5024\u306e\u7b49\u4fa1\u6027\u3068\u8868\u73fe\u306e\u7b49\u4fa1\u6027\u3092\u5206\u3051\u3066\u8003\u3048\u308b\u306e\u304c\u30dd\u30a4\u30f3\u30c8\u3067\u3059\u3002<\/p>\n
    \u3088\u304f\u3042\u308b\u8cea\u554f<\/h2>\n
    BigDecimal.ZERO.equals(new BigDecimal("0.0"))\u306ftrue\u3067\u3059\u304b\uff1f<\/h3>\n
    false\u3067\u3059\u3002BigDecimal.ZERO\u306escale\u306f0\u3067\u3001new BigDecimal("0.0")\u306escale\u306f1\u306a\u306e\u3067\u3001equals()\u3067\u306f\u4e00\u81f4\u3057\u307e\u305b\u3093\u3002\u6570\u5024\u3068\u3057\u30660\u304b\u3092\u5224\u5b9a\u3059\u308b\u306a\u3089value.compareTo(BigDecimal.ZERO) == 0\u3092\u4f7f\u3044\u307e\u3059\u3002<\/p>\n
    compareTo()\u304c0\u306a\u3089equals()\u3082true\u306b\u306a\u308a\u307e\u3059\u304b\uff1f<\/h3>\n
    \u5fc5\u305a\u3067\u306f\u3042\u308a\u307e\u305b\u3093\u3002\u6570\u5024\u304c\u7b49\u3057\u304f\u3066\u3082scale\u304c\u9055\u3048\u3070compareTo()\u306f0\u3001equals()\u306ffalse\u306b\u306a\u308a\u307e\u3059\u3002BigDecimal\u306e\u81ea\u7136\u9806\u5e8f\u306fequals\u3068\u6574\u5408\u3057\u306a\u3044\u70b9\u304c\u516c\u5f0fAPI\u306b\u3082\u660e\u8a18\u3055\u308c\u3066\u3044\u307e\u3059\u3002<\/p>\n
    \u6bce\u56destripTrailingZeros()\u3057\u3066\u304b\u3089equals()\u3059\u308c\u3070\u3088\u3044\u3067\u3059\u304b\uff1f<\/h3>\n
    \u6570\u5024\u6bd4\u8f03\u304c\u76ee\u7684\u306a\u3089compareTo()\u306e\u65b9\u304c\u76f4\u63a5\u7684\u3067\u3059\u3002stripTrailingZeros()\u306f\u8868\u73fe\u3092\u5909\u3048\u3001\u5024\u306b\u3088\u3063\u3066\u306fscale\u304c\u8ca0\u306b\u306a\u308b\u3053\u3068\u3082\u3042\u308b\u305f\u3081\u3001\u6b63\u898f\u5316\u30eb\u30fc\u30eb\u3068\u3057\u3066\u63a1\u7528\u3059\u308b\u5834\u5408\u306b\u9650\u3063\u3066\u4f7f\u3046\u65b9\u304c\u610f\u56f3\u3092\u660e\u78ba\u306b\u3067\u304d\u307e\u3059\u3002<\/p>\n
    \u65e2\u5b58\u30b3\u30fc\u30c9\u3067BigDecimal\u306e`equals()`\u3092\u4f7f\u3063\u3066\u3044\u308b\u7b87\u6240\u3092\u78ba\u8a8d\u3057\u3001\u305d\u308c\u304c\u300c\u6570\u5024\u6bd4\u8f03\u300d\u306a\u306e\u304b\u300cscale\u3092\u542b\u3080\u8868\u73fe\u6bd4\u8f03\u300d\u306a\u306e\u304b\u3092\u4e00\u5ea6\u5207\u308a\u5206\u3051\u3066\u307f\u3066\u304f\u3060\u3055\u3044\u3002<\/p>\n","protected":false},"featured_media":6417,"template":"","meta":{"ssp_meta_title":"BigDecimal equals\u3068compareTo\u306e\u9055\u3044\uff5cscale\u3092\u89e3\u8aac","ssp_meta_description":"Java BigDecimal\u30670.0\u30680.00\u304cequals\u3067false\u306b\u306a\u308b\u7406\u7531\u3092\u3001scale\u306e\u4ed5\u7d44\u307f\u304b\u3089\u89e3\u8aac\u3002compareTo\u3068\u306e\u9055\u3044\u3001\u91d1\u984d\u6bd4\u8f03\u3001hashCode\u3001stripTrailingZeros\u306e\u6ce8\u610f\u70b9\u307e\u3067\u6574\u7406\u3057\u307e\u3059\u3002","ssp_meta_keyword":"BigDecimal equals compareTo,BigDecimal 0.0 0.00,BigDecimal scale,BigDecimal \u6bd4\u8f03,BigDecimal compareTo 0,BigDecimal equals false,BigDecimal stripTrailingZeros","ssp_meta_canonical":""},"route_category":[9],"_links":{"self":[{"href":"https:\/\/route-zero.com\/recruit\/wp-json\/wp\/v2\/route\/6411"}],"collection":[{"href":"https:\/\/route-zero.com\/recruit\/wp-json\/wp\/v2\/route"}],"about":[{"href":"https:\/\/route-zero.com\/recruit\/wp-json\/wp\/v2\/types\/route"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/route-zero.com\/recruit\/wp-json\/wp\/v2\/media\/6417"}],"wp:attachment":[{"href":"https:\/\/route-zero.com\/recruit\/wp-json\/wp\/v2\/media?parent=6411"}],"wp:term":[{"taxonomy":"route_category","embeddable":true,"href":"https:\/\/route-zero.com\/recruit\/wp-json\/wp\/v2\/route_category?post=6411"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}