{"id":662,"date":"2019-04-14T16:15:20","date_gmt":"2019-04-14T08:15:20","guid":{"rendered":"http:\/\/prayerlaputa.com\/?p=662"},"modified":"2019-09-14T21:30:36","modified_gmt":"2019-09-14T13:30:36","slug":"google-guava%e4%bd%bf%e7%94%a8%e6%95%99%e7%a8%8b%e7%b3%bb%e5%88%97%ef%bc%881%ef%bc%89-string%e7%9b%b8%e5%85%b3","status":"publish","type":"post","link":"http:\/\/prayerlaputa.com\/?p=662","title":{"rendered":"google guava\u4f7f\u7528\u6559\u7a0b\u7cfb\u5217\uff081\uff09-String\u76f8\u5173"},"content":{"rendered":"

\u6ce8\u610f\uff1a\u672c\u6587\u6863\u57fa\u4e8egoogle guava 28 wiki<\/strong><\/p>\n

\n

Joiner<\/h1>\n

\u8fde\u63a5\u5668<\/p>\n

\u5c06\u5b57\u7b26\u4e32\u62fc\u63a5<\/h3>\n
Joiner joiner = Joiner.on(\"; \").skipNulls();\r\nreturn joiner.join(\"Harry\", null, \"Ron\", \"Hermione\");\r\n<\/code><\/pre>\n
\u8fd4\u56deHarry; Ron; Hermione<\/code>
\nskipNulls()\u65b9\u6cd5\u662f\u76f4\u63a5\u5ffd\u7565null\uff0c\u4f7f\u7528useForNull(String)\u65b9\u6cd5\u53ef\u4ee5\u7ed9\u5b9a\u67d0\u4e2a\u5b57\u7b26\u4e32\u6765\u66ff\u6362null\uff0c\u5373<\/p>\n
Joiner joiner = Joiner.on(\"; \").useForNull(\"\u66ff\u6362\u5b57\u7b26\u4e32\");\r\n<\/code><\/pre>\n
<\/p>\n
\u8fde\u63a5\u5bf9\u8c61\u7c7b\u578b<\/h3>\n
Joiner\u4e5f\u53ef\u4ee5\u7528\u6765\u8fde\u63a5\u5bf9\u8c61\u7c7b\u578b\uff0c\u5728\u8fd9\u79cd\u60c5\u51b5\u4e0b\uff0c\u5b83\u4f1a\u628a\u5bf9\u8c61\u7684toString()\u503c\u8fde\u63a5\u8d77\u6765\u3002<\/p>\n
Joiner.on(\",\").join(Arrays.asList(1, 5, 7)); \/\/ returns \"1,5,7\"\r\n<\/code><\/pre>\n
\u6ce8\u610f<\/h2>\n
joiner\u5b9e\u4f8b\u603b\u662f\u4e0d\u53ef\u53d8\u7684\u3002\u7528\u6765\u5b9a\u4e49joiner\u76ee\u6807\u8bed\u4e49\u7684\u914d\u7f6e\u65b9\u6cd5\u603b\u4f1a\u8fd4\u56de\u4e00\u4e2a\u65b0\u7684joiner\u5b9e\u4f8b\u3002\u8fd9\u4f7f\u5f97joiner\u5b9e\u4f8b\u90fd\u662f\u7ebf\u7a0b\u5b89\u5168\u7684\uff0c\u4f60\u53ef\u4ee5\u5c06\u5176\u5b9a\u4e49\u4e3astatic final\u5e38\u91cf\u3002<\/p>\n
Splitter<\/h1>\n
\u5b57\u7b26\u4e32\u62c6\u5206\u5de5\u5177
\nJDK\u63d0\u4f9b\u7684String.split\u65b9\u6cd5 \u4e00\u4e9b\u5947\u602a\u7684\u5730\u65b9\uff0c\u4f8b\u5982\uff1a\u4f1a\u4e22\u5f03\u6389\u5c3e\u90e8\u5206\u9694\u7b26\u3002
\n\u4f8b\u5b50\uff1a<\/p>\n
\",a,,b,\".split(\",\")  \r\n<\/code><\/pre>\n
\u8fd4\u56de\u7ed3\u679c\u662f\uff1a<\/p>\n
\"\", \"a\", \"\", \"b\"\r\n<\/code><\/pre>\n
Splitter\u5219\u63d0\u4f9b\u4e86\u66f4\u6e05\u6670\u7684\u63a5\u53e3\uff1a<\/p>\n
Splitter.on(',')\r\n    .trimResults()\r\n    .omitEmptyStrings()\r\n    .split(\"foo,bar,,   qux\");\r\n<\/code><\/pre>\n
\u8fd4\u56de\u7ed3\u679c\u4e3a\"foo\", \"bar\", \"qux\"<\/code><\/p>\n
Splitter\u5de5\u5382<\/h3>\n\n\n\n\n\n\n\n\n\n
\u65b9\u6cd5<\/th>\n\u63cf\u8ff0<\/th>\n\u793a\u4f8b<\/th>\n<\/tr>\n<\/thead>\n
Splitter.on(char)<\/td>\n\u6309\u5355\u4e2a\u5b57\u7b26\u62c6\u5206<\/td>\nSplitter.on(\u2018;\u2019)<\/td>\n<\/tr>\n
Splitter.on(CharMatcher)<\/td>\n\u6309\u5b57\u7b26\u5339\u914d\u5668\u62c6\u5206<\/td>\nSplitter.on(CharMatcher.BREAKING_WHITESPACE)<\/td>\n<\/tr>\n
Splitter.on(String)<\/td>\n\u6309\u5b57\u7b26\u4e32\u62c6\u5206<\/td>\nSplitter.on(“, “)<\/td>\n<\/tr>\n
Splitter.on(Pattern)
\nSplitter.onPattern(String)<\/td>\n		\u6309\u6b63\u5219\u8868\u8fbe\u5f0f\u62c6\u5206<\/td>\nSplitter.onPattern(\u201c\\r?\\n\u201d)<\/td>\n<\/tr>\n
Splitter.fixedLength(int)<\/td>\n\u6309\u56fa\u5b9a\u957f\u5ea6\u62c6\u5206\uff1b\u6700\u540e\u4e00\u6bb5\u53ef\u80fd\u6bd4\u7ed9\u5b9a\u957f\u5ea6\u77ed\uff0c\u4f46\u4e0d\u4f1a\u4e3a\u7a7a<\/td>\nSplitter.fixedLength(3)<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n
Splitter\u4fee\u9970\u7b26<\/h3>\n\n\n\n\n\n\n\n\n
\u65b9\u6cd5<\/th>\n\u63cf\u8ff0<\/th>\n<\/tr>\n<\/thead>\n
omitEmptyStrings()<\/td>\n\u4ece\u7ed3\u679c\u4e2d\u81ea\u52a8\u5ffd\u7565\u7a7a\u5b57\u7b26\u4e32<\/td>\n<\/tr>\n
trimResults()<\/td>\n\u79fb\u9664\u7ed3\u679c\u5b57\u7b26\u4e32\u7684\u524d\u5bfc\u7a7a\u767d\u548c\u5c3e\u90e8\u7a7a\u767d<\/td>\n<\/tr>\n
trimResults(CharMatcher)<\/td>\n\u7ed9\u5b9a\u5339\u914d\u5668\uff0c\u79fb\u9664\u7ed3\u679c\u5b57\u7b26\u4e32\u7684\u524d\u5bfc\u5339\u914d\u5b57\u7b26\u548c\u5c3e\u90e8\u5339\u914d\u5b57\u7b26<\/td>\n<\/tr>\n
limit(int)<\/td>\n\u9650\u5236\u62c6\u5206\u51fa\u7684\u5b57\u7b26\u4e32\u6570\u91cf<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n
\u6ce8\uff1a\u5982\u679c\u9700\u8981\u8fd4\u56deList\u800c\u4e0d\u662f\u6570\u7ec4\uff0c\u5219\u8c03\u7528splitToList()<\/code>\u3001\u800c\u4e0d\u662fsplit()<\/code><\/strong><\/p>\n
\u6ce8\u610f<\/h2>\n
splitter\u5b9e\u4f8b\u603b\u662f\u4e0d\u53ef\u53d8\u7684\u3002\u7528\u6765\u5b9a\u4e49splitter\u76ee\u6807\u8bed\u4e49\u7684\u914d\u7f6e\u65b9\u6cd5\u603b\u4f1a\u8fd4\u56de\u4e00\u4e2a\u65b0\u7684splitter\u5b9e\u4f8b\u3002\u8fd9\u4f7f\u5f97splitter\u5b9e\u4f8b\u90fd\u662f\u7ebf\u7a0b\u5b89\u5168\u7684\uff0c\u4f60\u53ef\u4ee5\u5c06\u5176\u5b9a\u4e49\u4e3astatic final\u5e38\u91cf\u3002<\/p>\n
Map Splitter<\/h2>\n
\u53ef\u4ee5\u901a\u8fc7withKeyValueSeparator()<\/code>\u6307\u5b9a\u7b2c\u4e8c\u4e2a\u5206\u9694\u7b26\uff0c\u7528\u4e8e\u4ece\u5b57\u7b26\u4e32\u4e2d\u53cd\u5e8f\u5217\u51fa\u4e00\u4e2amap\uff0c\u5c06\u4f1a\u8fd4\u56de\u4e00\u4e2aMap<String, String>
\n\u4f8b\u5982\uff1a\u5bf9url\u4e2d\u7684\u67e5\u8be2\u5b57\u7b26\u4e32\"id=123&name=green\"\u8fdb\u884c\u5206\u5272<\/code><\/p>\n
final Map<String, String> join = Splitter.on(\"&\").withKeyValueSeparator(\"=\").split(\"id=123&name=green\");\r\n<\/code><\/pre>\n
Map Joinner<\/h2>\n
\u4f8b\u5982\uff1a\u751f\u4ea7\u4e00\u4e2a\u67e5\u8be2id: 123,name: green\u7684\u5b66\u751f\u4fe1\u606f\u7684url\u3002<\/code><\/p>\n
Joiner.on(\"&\").withKeyValueSeparator(\"=\").join(ImmutableMap.of(\"id\", \"123\", \"name\", \"green\"));\r\n<\/code><\/pre>\n
CharMatcher<\/h1>\n
CharMatcher\u5b9e\u4f8b\u9996\u5148\u4ee3\u8868\u6982\u5ff51\uff1a\u600e\u4e48\u624d\u7b97\u5339\u914d\u5b57\u7b26\uff1f\u7136\u540e\u5b83\u8fd8\u63d0\u4f9b\u4e86\u5f88\u591a\u64cd\u4f5c\u6982\u5ff52\uff1a\u5982\u4f55\u5904\u7406\u8fd9\u4e9b\u5339\u914d\u5b57\u7b26\uff1f<\/p>\n
String noControl = CharMatcher.JAVA_ISO_CONTROL.removeFrom(string); \/\/\u79fb\u9664control\u5b57\u7b26\r\nString theDigits = CharMatcher.DIGIT.retainFrom(string); \/\/\u53ea\u4fdd\u7559\u6570\u5b57\u5b57\u7b26\r\nString spaced = CharMatcher.WHITESPACE.trimAndCollapseFrom(string, ' ');\/\/\u53bb\u9664\u4e24\u7aef\u7684\u7a7a\u683c\uff0c\u5e76\u628a\u4e2d\u95f4\u7684\u8fde\u7eed\u7a7a\u683c\u66ff\u6362\u6210\u5355\u4e2a\u7a7a\u683c\r\nString noDigits = CharMatcher.JAVA_DIGIT.replaceFrom(string, \"*\"); \/\/\u7528*\u53f7\u66ff\u6362\u6240\u6709\u6570\u5b57\r\nString lowerAndDigit = CharMatcher.JAVA_DIGIT.or(CharMatcher.JAVA_LOWER_CASE).retainFrom(string);\/\/ \u53ea\u4fdd\u7559\u6570\u5b57\u548c\u5c0f\u5199\u5b57\u6bcd\r\n<\/code><\/pre>\n
\u6ce8\u610f\uff1aCharMatcher\u53ea\u5904\u7406char\u7c7b\u578b\u4ee3\u8868\u7684\u5b57\u7b26\uff1b\u5b83\u4e0d\u80fd\u7406\u89e30x10000\u52300x10FFFF\u7684Unicode \u589e\u8865\u5b57\u7b26\u3002\u8fd9\u4e9b\u903b\u8f91\u5b57\u7b26\u4ee5\u4ee3\u7406\u5bf9[surrogate pairs]\u7684\u5f62\u5f0f\u7f16\u7801\u8fdb\u5b57\u7b26\u4e32\uff0c\u800cCharMatcher\u53ea\u80fd\u5c06\u8fd9\u79cd\u903b\u8f91\u5b57\u7b26\u770b\u5f85\u6210\u4e24\u4e2a\u72ec\u7acb\u7684\u5b57\u7b26\u3002<\/p>\n
CharMatcher\u5de5\u5382\u65b9\u6cd5<\/h3>\n
any()\r\nnone()\r\nwhitespace()\r\nbreakingWhitespace()\r\ninvisible()\r\ndigit()\r\njavaLetter()\r\njavaDigit()\r\njavaLetterOrDigit()\r\njavaIsoControl()\r\njavaLowerCase()\r\njavaUpperCase()\r\nascii()\r\nsingleWidth()\r\n<\/code><\/pre>\n
\u5176\u4ed6\uff1a<\/p>\n\n\n\n\n\n\n\n
\u65b9\u6cd5<\/th>\n\u63cf\u8ff0<\/th>\n<\/tr>\n<\/thead>\n
anyOf(CharSequence)<\/td>\n\u679a\u4e3e\u5339\u914d\u5b57\u7b26\u3002\u5982CharMatcher.anyOf(\u201caeiou\u201d)\u5339\u914d\u5c0f\u5199\u82f1\u8bed\u5143\u97f3<\/td>\n<\/tr>\n
is(char)<\/td>\n\u7ed9\u5b9a\u5355\u4e00\u5b57\u7b26\u5339\u914d\u3002<\/td>\n<\/tr>\n
inRange(char, char)<\/td>\n\u7ed9\u5b9a\u5b57\u7b26\u8303\u56f4\u5339\u914d\uff0c\u5982CharMatcher.inRange(\u2018a\u2019, \u2018z\u2019)<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n
\u6b64\u5916\uff0cCharMatcher\u8fd8\u6709negate()\u3001and(CharMatcher)\u548cor(CharMatcher)\u65b9\u6cd5\u3002<\/p>\n
\u4f7f\u7528CharMatchers<\/h3>\n\n\n\n\n\n\n\n\n\n\n
\u65b9\u6cd5<\/th>\n\u63cf\u8ff0<\/th>\n<\/tr>\n<\/thead>\n
collapseFrom(CharSequence, char)<\/td>\n\u628a\u6bcf\u7ec4\u8fde\u7eed\u7684\u5339\u914d\u5b57\u7b26\u66ff\u6362\u4e3a\u7279\u5b9a\u5b57\u7b26\u3002\u5982WHITESPACE.collapseFrom(string, ‘ ‘)<\/td>\n<\/tr>\n
matchesAllOf(CharSequence)<\/td>\n\u6d4b\u8bd5\u662f\u5426\u5b57\u7b26\u5e8f\u5217\u4e2d\u7684\u6240\u6709\u5b57\u7b26\u90fd\u5339\u914d\u3002<\/td>\n<\/tr>\n
removeFrom(CharSequence)<\/td>\n\u4ece\u5b57\u7b26\u5e8f\u5217\u4e2d\u79fb\u9664\u6240\u6709\u5339\u914d\u5b57\u7b26\u3002<\/td>\n<\/tr>\n
retainFrom(CharSequence)<\/td>\n\u5728\u5b57\u7b26\u5e8f\u5217\u4e2d\u4fdd\u7559\u5339\u914d\u5b57\u7b26\uff0c\u79fb\u9664\u5176\u4ed6\u5b57\u7b26\u3002<\/td>\n<\/tr>\n
trimFrom(CharSequence)<\/td>\n\u79fb\u9664\u5b57\u7b26\u5e8f\u5217\u7684\u524d\u5bfc\u5339\u914d\u5b57\u7b26\u548c\u5c3e\u90e8\u5339\u914d\u5b57\u7b26\u3002<\/td>\n<\/tr>\n
replaceFrom(CharSequence, CharSequence)<\/td>\n\u7528\u7279\u5b9a\u5b57\u7b26\u5e8f\u5217\u66ff\u4ee3\u5339\u914d\u5b57\u7b26\u3002<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n
\u6240\u6709\u8fd9\u4e9b\u65b9\u6cd5\u8fd4\u56deString\uff0c\u9664\u4e86matchesAllOf\u8fd4\u56de\u7684\u662fboolean\u3002<\/p>\n
Charsets<\/h1>\n
\u83b7\u53d6\u5b57\u7b26\u96c6\u65f6\uff0c\u4e0d\u8981\u8fd9\u6837\uff1a<\/p>\n
try {\r\n  bytes = string.getBytes(\"UTF-8\");\r\n} catch (UnsupportedEncodingException e) {\r\n  \/\/ how can this possibly happen?\r\n  throw new AssertionError(e);\r\n}\r\n<\/code><\/pre>\n
\u800c\u662f\u5e94\u8be5\uff1a<\/p>\n
bytes = string.getBytes(Charsets.UTF_8);\r\n<\/code><\/pre>\n
Charsets\u9488\u5bf9\u6240\u6709Java\u5e73\u53f0\u90fd\u8981\u4fdd\u8bc1\u652f\u6301\u7684\u516d\u79cd\u5b57\u7b26\u96c6\u63d0\u4f9b\u4e86\u5e38\u91cf\u5f15\u7528\u3002\u5c1d\u8bd5\u4f7f\u7528\u8fd9\u4e9b\u5e38\u91cf\uff0c\u800c\u4e0d\u662f\u901a\u8fc7\u540d\u79f0\u83b7\u53d6\u5b57\u7b26\u96c6\u5b9e\u4f8b\u3002<\/p>\n
CaseFormat<\/h1>\n
CaseFormat\u88ab\u7528\u6765\u65b9\u4fbf\u5730\u5728\u5404\u79cdASCII\u5927\u5c0f\u5199\u89c4\u8303\u95f4\u8f6c\u6362\u5b57\u7b26\u4e32\u2014\u2014\u6bd4\u5982\uff0c\u7f16\u7a0b\u8bed\u8a00\u7684\u547d\u540d\u89c4\u8303\u3002CaseFormat\u652f\u6301\u7684\u683c\u5f0f\u5982\u4e0b\uff1a<\/p>\n\n\n\n\n\n\n\n\n\n
\u683c\u5f0f<\/th>\n\u8303\u4f8b<\/th>\n<\/tr>\n<\/thead>\n
LOWER_CAMEL<\/td>\nlowerCamel<\/td>\n<\/tr>\n
LOWER_HYPHEN<\/td>\nlower-hyphen<\/td>\n<\/tr>\n
LOWER_UNDERSCORE<\/td>\nlower_underscore<\/td>\n<\/tr>\n
UPPER_CAMEL<\/td>\nUpperCamel<\/td>\n<\/tr>\n
UPPER_UNDERSCORE<\/td>\nUPPER_UNDERSCORE<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n
\u53c2\u8003\u6587\u6863<\/h1>\n