{"id":441890,"date":"2021-04-16T17:58:01","date_gmt":"2021-04-16T09:58:01","guid":{"rendered":"http:\/\/4563.org\/?p=441890"},"modified":"2021-04-16T17:58:01","modified_gmt":"2021-04-16T09:58:01","slug":"java-%e8%af%ad%e6%b3%95%e7%b3%96%e7%9a%84%e6%8e%a2%e8%ae%a8%ef%bc%9a-%e5%a6%82%e4%bd%95%e7%ae%80%e5%8c%96%e6%b2%a1%e6%9c%89-else-%e7%9a%84-if-%e8%af%ad%e5%8f%a5%e5%86%99%e6%b3%95","status":"publish","type":"post","link":"http:\/\/4563.org\/?p=441890","title":{"rendered":"Java \u8bed\u6cd5\u7cd6\u7684\u63a2\u8ba8\uff1a \u5982\u4f55\u7b80\u5316\u6ca1\u6709 else \u7684 if \u8bed\u53e5\u5199\u6cd5"},"content":{"rendered":"
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Java \u8bed\u6cd5\u7cd6\u7684\u63a2\u8ba8\uff1a \u5982\u4f55\u7b80\u5316\u6ca1\u6709 else \u7684 if \u8bed\u53e5\u5199\u6cd5 <\/h1>\n

<\/p>\n

\n
\u8cc7\u6df1\u5927\u4f6c : rizon <\/span> <\/i> 3<\/span> <\/div>\n
<\/div>\n<\/p><\/div>\n<\/p><\/div>\n<\/p><\/div>\n
<\/p>\n
 \/\/java \u4e2d \u5bf9\u4e8e\u6709\u8fd4\u56de\u503c\u7684\u8bed\u53e5\u662f\u5fc5\u987b\u8981\u8d4b\u503c\u7ed9\u4e00\u4e2a\u5bf9\u8c61\u7684\u3002 \/\/\u4e5f\u5c31\u662f\u8bf4   \/\/\u8fd9\u4e2a\u8bed\u53e5\u662f\u7f16\u8bd1\u4e0d\u8fc7\u7684 1==1;  \/\/ \u8fd9\u6837\u901a\u8fc7\u77ed\u8def\u7684\u65b9\u5f0f\u53bb\u7b80\u5316 if \u8bed\u53e5\u662f\u4e0d\u884c\u7684 1==2&&method();  \/\/\u6240\u4ee5\u5bf9\u4e8e\u6ca1\u6709\u8fd4\u56de\u503c\u7684 if \u8bed\u53e5\u53ea\u80fd\u8001\u5b9e\u7684\u5199\u6210 if(1==2)   method();    \/\/\u4f46\u662f\u8fd9\u6837\u7684\u8bdd\u5982\u679c\u653e\u5230 lamda \u8868\u8fbe\u5f0f\u4e2d\u5c31\u4f1a\u8ba9\u8bed\u53e5\u53d8\u5f97\u5f88\u590d\u6742  \/\/\u7406\u60f3\u72b6\u6001 1 list.foreach(val->1==2&&method(val));  \/\/\u7406\u60f3\u72b6\u6001 2 \u8fd9\u91cc\u7684 void \u8868\u793a\u6ca1\u6709\u4efb\u4f55\u64cd\u4f5c\uff0cjava \u4e5f\u4e0d\u652f\u6301\u8fd9\u79cd\u7a7a\u64cd\u4f5c list.foreach(val->1==2?method(val)); list.foreach(val->1==2?method(val):void);  \/\/\u73b0\u5b9e list.foreach(val->{ if(1==2)   method(val); });   <\/code><\/pre>\n
\u6240\u4ee5\u6709\u4ec0\u4e48\u66f4\u597d\u7684\u529e\u6cd5\u5417\uff1f<\/p>\n<\/p><\/div>\n
 \u5927\u4f6c\u6709\u8a71\u8aaa<\/b> (20<\/span>)        <\/div>\n
 <\/div>\n<\/p><\/div>\n<\/p><\/div>\n
    \n
  • \n
    \n
    \n
     \u8cc7\u6df1\u5927\u4f6c : abersheeran <\/span>  <\/div>\n
     <\/i>            <\/span> <\/div>\n<\/p><\/div>\n
                                                                 \u6211\u89c9\u5f97\u5427\uff0c\u4f60\u90fd\u7528 Java \u4e86\u5c31\u522b\u60f3\u7740\u73a9\u82b1\u6d3b\u4e86\u3002\u8fd9\u8bed\u8a00\u6700\u5927\u7684\u5de5\u4e1a\u4f18\u52bf\u5c31\u662f\u4f60\u73a9\u4e0d\u51fa\u4ec0\u4e48\u82b1\u6d3b\u3002\u80fd\u73a9\u82b1\u706b\u7684\uff0c\u57fa\u672c\u90fd\u88ab\u4eba\u8bf4\u662f\u91cd\u6784\u706b\u846c\u573a\u4e86\u3002                                                            <\/div>\n<\/p><\/div>\n<\/li>\n
  • \n
    \n
    \n
     \u8cc7\u6df1\u5927\u4f6c : sylxjtu <\/span>  <\/div>\n
     <\/i>            <\/span> <\/div>\n<\/p><\/div>\n
                                                                 \u5148\u8f6c\u6210 stream\uff0cfilter \u4e4b\u540e\u518d foreach                                                            <\/div>\n<\/p><\/div>\n<\/li>\n
  • \n
    \n
    \n
     \u8cc7\u6df1\u5927\u4f6c : zydxn <\/span>  <\/div>\n
     <\/i>            <\/span> <\/div>\n<\/p><\/div>\n
                                                                 \u6211\u89c9\u5f97\u4e0d\u5728 foreach \u91cc\u9762\u7528\u65b9\u6cd5\u5f15\u7528\u4e4b\u7c7b\u7684\u5c31\u6ca1\u5fc5\u8981\u7528 foreach\uff0c\u6b63\u5e38\u5199 for \u5faa\u73af\u5c31\u884c\u4e86
    \u8981\u4e48\u5c31\u662f stream().filter(predicate).forEach(this::method)                                                            <\/div>\n<\/p><\/div>\n<\/li>\n
  • \n
    \n
    \n
     \u8cc7\u6df1\u5927\u4f6c : zhuweiyou <\/span>  <\/div>\n
     <\/i>            <\/span> <\/div>\n<\/p><\/div>\n
                                                                 .filter()
    .forEach()                                                            <\/div>\n<\/p><\/div>\n<\/li>\n
  • \n
    \n
    \n
     \u8cc7\u6df1\u5927\u4f6c : beichenhpy <\/span>  <\/div>\n
     <\/i>            <\/span> <\/div>\n<\/p><\/div>\n
                                                                 \u76f4\u63a5\u5199\u6709\u5565\u5f0a\u7aef\u5417\uff1f
    \u8bed\u6cd5\u7cd6\u4e0d\u662f\u4e3a\u4e86\u4f18\u5316\u624d\u641e\u7684\u561b\uff1f                                                            <\/div>\n<\/p><\/div>\n<\/li>\n
  • \n
    \n
    \n
     \u8cc7\u6df1\u5927\u4f6c : chendy <\/span>  <\/div>\n
     <\/i>            <\/span> <\/div>\n<\/p><\/div>\n
                                                                 filter + forEach
    \u4e0d\u8fc7\u5c31\u8001\u8001\u5b9e\u5b9e\u5199\u4e2a for + if \u4e5f\u4e0d\u96be\u770b\u554a\uff08\u8bf4\u4e0d\u5b9a\u6548\u7387\u8fd8\u66f4\u9ad8\uff09\u2026\u2026                                                            <\/div>\n<\/p><\/div>\n<\/li>\n
  • \n
    \n
    \n
     \u4e3b<\/span> \u8cc7\u6df1\u5927\u4f6c : rizon <\/span>  <\/div>\n
     <\/i>            <\/span> <\/div>\n<\/p><\/div>\n
                                                                 \u597d\u5427 \u770b\u6765 java \u5c31\u522b\u60f3\u90a3\u4e48\u591a\u82b1\u6837\u4e86 \u54c8\u54c8                                                            <\/div>\n<\/p><\/div>\n<\/li>\n
  • \n
    \n
    \n
     \u8cc7\u6df1\u5927\u4f6c : bthulu <\/span>  <\/div>\n
     <\/i>            <\/span> <\/div>\n<\/p><\/div>\n
                                                                 \u4f60\u53ef\u4ee5\u5199\u4e2a\u9759\u6001\u65b9\u6cd5
    public class Utils {
     public static <T, R> R ifTrueThenDo(boolean b, T params, Function<T, R> callback) {
     if (b) {
     return callback.apply(params);
     }
     return null;
     }
    }<\/p>\n
    \u7136\u540e\u5728\u522b\u7684\u7c7b\u91cc\u5f15\u5165:
    import static xxx.Utils.ifTrueThenDo;<\/p>\n
    \u63a5\u4e0b\u6765\u4f60\u5c31\u53ef\u4ee5\u4e00\u884c\u8bed\u53e5\u5b8c\u6210\u4f60\u7684\u8fd9\u4e9b\u529f\u80fd\u4e86, \u6bd4\u5982:
    ifTrueThenDo(1==2, val, (val) -> method(val))                                                            <\/div>\n<\/p><\/div>\n<\/li>\n
  • \n
    \n
    \n
     \u8cc7\u6df1\u5927\u4f6c : jones2000 <\/span>  <\/div>\n
     <\/i>            <\/span> <\/div>\n<\/p><\/div>\n
                                                                 \u4ee3\u7801\u80fd\u9ad8\u6548\u7684\u89e3\u51b3\u95ee\u9898\u4e0d\u5c31\u884c\u4e86. \u5176\u4ed6\u7684\u90fd\u4e0d\u91cd\u8981. \u4ee3\u7801\u6700\u540e\u662f\u7f16\u7a0b\u6210\u4ea7\u54c1\u7ed9\u5ba2\u6237\u7528, \u5ba2\u6237\u624d\u4e0d\u7ba1\u4f60\u7528\u4ec0\u4e48\u8bed\u6cd5,\u8bed\u8a00.                                                            <\/div>\n<\/p><\/div>\n<\/li>\n
  • \n
    \n
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     \u8cc7\u6df1\u5927\u4f6c : Kasumi20 <\/span>  <\/div>\n
     <\/i>            <\/span> <\/div>\n<\/p><\/div>\n
                                                                 \u7528 Kotlin\uff0c\u4f60\u53ef\u4ee5\u5b8c\u5168\u4e0d\u7528\u5199 if \u8bed\u53e5                                                            <\/div>\n<\/p><\/div>\n<\/li>\n
  • \n
    \n
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     \u8cc7\u6df1\u5927\u4f6c : CrazyMonkeyV <\/span>  <\/div>\n
     <\/i>            <\/span> <\/div>\n<\/p><\/div>\n
                                                                 \u4e0d\u77e5\u9053 Java \u884c\u4e0d\u884c\uff0c\u5b57\u5178\u4e86\u89e3\u4e0b                                                            <\/div>\n<\/p><\/div>\n<\/li>\n
  • \n
    \n
    \n
     \u8cc7\u6df1\u5927\u4f6c : yazinnnn <\/span>  <\/div>\n
     <\/i>            <\/span> <\/div>\n<\/p><\/div>\n
                                                                 \u6211\u6bd4\u8f83\u9707\u60ca 1==1;\u5c45\u7136\u7f16\u8bd1\u4e0d\u8fc7\u53bb<\/p>\n
    \u867d\u7136 java \u7684 stream \u6bd4\u8f83\u5570\u55e6\u6666\u6da9,\u4f46\u662f\u529f\u80fd\u8fd8\u662f\u9f50\u5168\u7684…
    \u4f60\u89c9\u5f97\u4e0d\u5168\u7684\u8bdd\u53ef\u4ee5\u7528 kotlin \u5e93\u63d0\u4f9b\u7684\u6269\u5c55\u65b9\u6cd5                                                            <\/div>\n<\/p><\/div>\n<\/li>\n
  • \n
    \n
    \n
     \u8cc7\u6df1\u5927\u4f6c : ychost <\/span>  <\/div>\n
     <\/i>            <\/span> <\/div>\n<\/p><\/div>\n
                                                                 \u6211\u5012\u662f\u5e0c\u671b Java \u80fd\u5f15\u5165\u53ef\u9009\u94fe\uff0cNullPointerException \u592a\u8ba8\u538c\u4e86                                                            <\/div>\n<\/p><\/div>\n<\/li>\n
  • \n
    \n
    \n
     \u8cc7\u6df1\u5927\u4f6c : CantSee <\/span>  <\/div>\n
     <\/i>            <\/span> <\/div>\n<\/p><\/div>\n
                                                                 \u7ed9\u4ed6\u5305\u88c5\u51e0\u5c42,\u5305\u88c5\u7684\u522b\u4eba\u53d1\u73b0\u4e0d\u4e86                                                            <\/div>\n<\/p><\/div>\n<\/li>\n
  • \n
    \n
    \n
     \u8cc7\u6df1\u5927\u4f6c : baozijun <\/span>  <\/div>\n
     <\/i>            <\/span> <\/div>\n<\/p><\/div>\n
                                                                 @ychost #13 Option \u5e94\u8be5\u53ef\u4ee5\u6ee1\u8db3                                                            <\/div>\n<\/p><\/div>\n<\/li>\n
  • \n
    \n
    \n
     \u8cc7\u6df1\u5927\u4f6c : ychost <\/span>  <\/div>\n
     <\/i>            <\/span> <\/div>\n<\/p><\/div>\n
                                                                 @baozijun Optional \u5199\u8d77\u6765\u6709\u70b9\u4e0d\u723d\uff0c\u8fd8\u662f\u4e60\u60ef ?. \u8fd9\u6837\u7684\u8bed\u6cd5\u7cd6 \u6216\u8005 ?? \u4e5f\u53ef\u4ee5                                                            <\/div>\n<\/p><\/div>\n<\/li>\n
  • \n
    \n
    \n
     \u8cc7\u6df1\u5927\u4f6c : dallaslu <\/span>  <\/div>\n
     <\/i>            <\/span> <\/div>\n<\/p><\/div>\n
                                                                 \u8fd9\u8fd8\u8981\u8fdb\u4e00\u6b65\u7b80\u5316\u5417\uff1f\u4f60\u7701\u7565\u4e86\u82b1\u62ec\u53f7\uff0c\u5df2\u7ecf\u662f\u79bb\u7ecf\u53db\u9053\u4e86\u597d\u5417\uff1f                                                            <\/div>\n<\/p><\/div>\n<\/li>\n
  • \n
    \n
    \n
     \u8cc7\u6df1\u5927\u4f6c : morimi2026 <\/span>  <\/div>\n
     <\/i>            <\/span> <\/div>\n<\/p><\/div>\n
                                                                 \u5982\u679c\u4e00\u4e2a\u8bed\u53e5\u80fd\u6e05\u6670\u8868\u8fbe\u610f\u601d\uff0c\u5c31\u4e0d\u7528\u7b80\u5316\u3002\u4f60\u4e3e\u4f8b\u7684\u5404\u79cd\u65b9\u5f0f\uff0c\u54ea\u6015 java \u652f\u6301\uff0c\u90fd\u6ca1\u76f4\u63a5\u7528 if \u6765\u5199\u8868\u8fbe\u5f97\u6e05\u6670                                                            <\/div>\n<\/p><\/div>\n<\/li>\n
  • \n
    \n
    \n
     \u8cc7\u6df1\u5927\u4f6c : ScepterZ <\/span>  <\/div>\n
     <\/i>            <\/span> <\/div>\n<\/p><\/div>\n
                                                                 \u6211\u89c9\u5f97\u660e\u663e\u662f\u5148 filter \u518d foreach \u66f4\u597d\uff0c\u5728 foreach \u91cc\u5148\u505a\u4e2a\u5224\u65ad\u8fd9\u79cd\u5199\u6cd5\u540e\u7eed\u5bb9\u6613\u5fd8\u8bb0\u5bfc\u81f4\u51fa\u9519\u4ec0\u4e48\u7684
    \u5148 filter \u66f4\u7b26\u5408\u6b63\u5e38\u601d\u7ef4                                                            <\/div>\n<\/p><\/div>\n<\/li>\n
  • \n
    \n
    \n
     \u8cc7\u6df1\u5927\u4f6c : securityCoding <\/span>  <\/div>\n
     <\/i>            <\/span> <\/div>\n<\/p><\/div>\n
                                                                 \u4e1a\u52a1\u591a\u89c4\u5219\u5224\u65ad\u53ef\u4ee5\u5199\u6210\u8d23\u4efb\u94fe                                                            <\/div>\n<\/p><\/div>\n<\/li>\n
  • \n","protected":false},"excerpt":{"rendered":"
    Java \u8bed\u6cd5\u7cd6\u7684\u63a2\u8ba8\uff1a \u5982\u4f55\u7b80\u5316…<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[],"tags":[],"_links":{"self":[{"href":"http:\/\/4563.org\/index.php?rest_route=\/wp\/v2\/posts\/441890"}],"collection":[{"href":"http:\/\/4563.org\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/4563.org\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/4563.org\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/4563.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=441890"}],"version-history":[{"count":0,"href":"http:\/\/4563.org\/index.php?rest_route=\/wp\/v2\/posts\/441890\/revisions"}],"wp:attachment":[{"href":"http:\/\/4563.org\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=441890"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/4563.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=441890"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/4563.org\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=441890"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}