{"id":325297,"date":"2021-02-05T21:20:24","date_gmt":"2021-02-05T13:20:24","guid":{"rendered":"http:\/\/4563.org\/?p=325297"},"modified":"2021-02-05T21:20:24","modified_gmt":"2021-02-05T13:20:24","slug":"java-%e5%b0%b1%e5%ae%8c%e5%85%a8%e6%b2%a1%e6%9c%89%e5%8a%9e%e6%b3%95%e7%bb%99%e6%b3%9b%e5%9e%8b%e5%b1%9e%e6%80%a7%e4%b8%80%e4%b8%aa%e5%88%9d%e5%a7%8b%e5%8c%96%e7%9a%84%e5%80%bc%e5%90%97%ef%bc%9f","status":"publish","type":"post","link":"http:\/\/4563.org\/?p=325297","title":{"rendered":"Java \u5c31\u5b8c\u5168\u6ca1\u6709\u529e\u6cd5\u7ed9\u6cdb\u578b\u5c5e\u6027\u4e00\u4e2a\u521d\u59cb\u5316\u7684\u503c\u5417\uff1f"},"content":{"rendered":"
\n
\n
\n

Java \u5c31\u5b8c\u5168\u6ca1\u6709\u529e\u6cd5\u7ed9\u6cdb\u578b\u5c5e\u6027\u4e00\u4e2a\u521d\u59cb\u5316\u7684\u503c\u5417\uff1f <\/h1>\n

<\/p>\n

\n
\u8cc7\u6df1\u5927\u4f6c : abcbuzhiming <\/span> <\/i> 1<\/span> <\/div>\n
<\/div>\n<\/p><\/div>\n<\/p><\/div>\n<\/p><\/div>\n
\u4e00\u4e2a\u7c7b\uff0c\u542b\u6709\u4e00\u4e2a\u6cdb\u578b\u5c5e\u6027 T\uff0c\u6211\u5c1d\u8bd5\u4e86\u51e0\u4e4e\u6240\u6709\u7684\u529e\u6cd5\uff0c\u90fd\u4e0d\u80fd\u518d\u8fd9\u4e2a\u7c7b\u751f\u6210\u5bf9\u8c61\u7684\u65f6\u5019\u5c31\u7ed9\u8fd9\u4e2a T \u4e00\u4e2a\u9ed8\u8ba4\u503c\u3002\u641c\u4e86\u4e00\u5708\uff0c\u82f1\u6587\u7f51\u7ad9\u4e0a\u8bf4\u8fd9\u662f\u65e0\u6cd5\u505a\u5230\u7684\uff1f\uff1f\uff1f <\/div>\n
\u5927\u4f6c\u6709\u8a71\u8aaa<\/b> (14<\/span>) <\/div>\n
<\/div>\n<\/p><\/div>\n<\/p><\/div>\n
    \n
  • \n
    \n
    \n
    \u8cc7\u6df1\u5927\u4f6c : sagaxu <\/span> <\/div>\n
    <\/i> <\/span> <\/div>\n<\/p><\/div>\n
    \u53ef\u4ee5\u521d\u59cb\u5316\u4e3a null <\/div>\n<\/p><\/div>\n<\/li>\n
  • \n
    \n
    \n
    \u8cc7\u6df1\u5927\u4f6c : codehz <\/span> <\/div>\n
    <\/i> <\/span> <\/div>\n<\/p><\/div>\n
    \u7c7b\u578b\u64e6\u9664\u4e86\uff0c\u6240\u4ee5\u62ff\u4e0d\u5230\u7c7b\u578b\u4fe1\u606f\uff0c\u81ea\u7136\u65e0\u6cd5\u521d\u59cb\u5316\uff0c\u53d8\u901a\u7684\u65b9\u6cd5\u5c31\u662f\u52a0\u4e00\u4e2a Class<T> clazz \u7684\u53c2\u6570\uff08 <\/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
    \u7c7b\u578b\u64e6\u9664\uff0c\u62ff\u4e0d\u5230 T \u7684\u7c7b\u578b\uff0c\u65e0\u6cd5\u8bbe\u7f6e <\/div>\n<\/p><\/div>\n<\/li>\n
  • \n
    \n
    \n
    \u8cc7\u6df1\u5927\u4f6c : zpxshl <\/span> <\/div>\n
    <\/i> <\/span> <\/div>\n<\/p><\/div>\n
    \u53ef\u4ee5\u7684\u5427\u3002\u7528\u53cd\u5c04\u627e\u5230 t \u771f\u5b9e\u7c7b\u578b\uff0c\u53cd\u5c04\u751f\u6210\u5bf9\u5e94\u5bf9\u8c61 <\/div>\n<\/p><\/div>\n<\/li>\n
  • \n
    \n
    \n
    \u8cc7\u6df1\u5927\u4f6c : yeqizhang <\/span> <\/div>\n
    <\/i> <\/span> <\/div>\n<\/p><\/div>\n
    \u60f3\u4e86\u89e3\u4e0b\u4e3a\u4ec0\u4e48\u60f3\u8981\u8bbe\u7f6e\u4e00\u4e2a\u9ed8\u8ba4\u503c\uff1f <\/div>\n<\/p><\/div>\n<\/li>\n
  • \n
    \n
    \n
    \u8cc7\u6df1\u5927\u4f6c : zhzy0077 <\/span> <\/div>\n
    <\/i> <\/span> <\/div>\n<\/p><\/div>\n
    \u8fd9\u51e0\u4e4e\u662f\u552f\u4e00\u4e00\u79cd\u505a\u5230\u7684\u65b9\u6cd5\uff1a<\/p>\n

    import java.lang.reflect.*;<\/p>\n

    class Main {
    public static void main(String args[]) throws Exception {
    var baz = new Foo<Baz>() {};
    System.out.println(baz.bar);
    }
    }<\/p>\n

    class Baz {<\/p>\n

    }<\/p>\n

    class Foo<T> {
    T bar;<\/p>\n

    public Foo() throws Exception {
    Type actualTypeArgument = ((ParameterizedType)this.getClass()
    .getGenericSuperclass())
    .getActualTypeArguments() [0];<\/p>\n

    System.out.println(actualTypeArgument);<\/p>\n

    Class<T> clazz = (Class<T>) actualTypeArgument;
    bar = clazz.newInstance();
    }
    }<\/p>\n

    \u4f46\u662f\u4ee3\u4ef7\u662f\u5fc5\u987b\u5728\u6240\u6709\u521d\u59cb\u5316\u7684\u5730\u65b9\u8fd9\u4e48\u5199 new Foo<Baz>() {} \u800c\u4e14 newInstance \u4e5f\u4f1a\u5047\u8bbe\u4e00\u5b9a\u6709\u4e2a\u65e0\u53c2\u6784\u9020\u51fd\u6570\u3002
    \u6700\u6709\u540d\u7684\u4f7f\u7528\u573a\u666f\u5c31\u662f fastjson \u7684 TypeReference \u4e86, fastjson \u4e3a\u4e86\u5728\u8fd0\u884c\u65f6\u62ff\u5230\u6cdb\u578b\u7684\u4fe1\u606f\uff0c\u5c31\u901a\u8fc7\u8fd9\u4e2a\u4f20\u8fdb\u6765\u7684 https:\/\/github.com\/alibaba\/fastjson\/blob\/master\/src\/main\/java\/com\/alibaba\/fastjson\/TypeReference.java<\/p>\n

    \u4f60\u8fd9\u4e2a\u573a\u666f\u4e0b\u5176\u5b9e\u6784\u9020\u51fd\u6570\u4f20\u4e00\u4e2a Class<T>\u8fdb\u6765\u4f1a\u66f4\u76f4\u63a5\u4e00\u70b9 <\/p><\/div>\n<\/p><\/div>\n<\/li>\n

  • \n
    \n
    \n
    \u8cc7\u6df1\u5927\u4f6c : EminemW <\/span> <\/div>\n
    <\/i> <\/span> <\/div>\n<\/p><\/div>\n
    \u5148\u8bf4\u4e3a\u4ec0\u4e48\u8981\u8fd9\u4e48\u505a <\/div>\n<\/p><\/div>\n<\/li>\n
  • \n
    \n
    \n
    \u8cc7\u6df1\u5927\u4f6c : Takamine <\/span> <\/div>\n
    <\/i> <\/span> <\/div>\n<\/p><\/div>\n
    \u4f60\u65e2\u7136\u60f3\u7ed9\u4ed6\u521d\u59cb\u503c\uff0c\u90a3\u4ed6\u5c31\u521d\u59cb\u5316\u65f6\u5c31\u662f\u6709\u7c7b\u578b\u7684\u4e86\uff0c\u8fd9\u4e3a\u5565\u53c8\u8981\u7528\u6cdb\u578b\u5462\u3002 <\/div>\n<\/p><\/div>\n<\/li>\n
  • \n
    \n
    \n
    \u8cc7\u6df1\u5927\u4f6c : Jooooooooo <\/span> <\/div>\n
    <\/i> <\/span> <\/div>\n<\/p><\/div>\n
    \u5177\u4f53\u8bf4\u8bf4\u573a\u666f, \u611f\u89c9\u4e0d\u662f\u7528\u6cdb\u578b\u7684\u5730\u65b9 <\/div>\n<\/p><\/div>\n<\/li>\n
  • \n
    \n
    \n
    \u4e3b<\/span> \u8cc7\u6df1\u5927\u4f6c : abcbuzhiming <\/span> <\/div>\n
    <\/i> <\/span> <\/div>\n<\/p><\/div>\n
    @yeqizhang
    @EminemW
    @Jooooooooo <\/p>\n

    \u56e0\u4e3a\u8fd9\u73a9\u610f\u5982\u679c\u4e0d\u521d\u59cb\u5316\uff0c\u90a3\u4e48\u5e8f\u5217\u5316\u4e3a json \u540e\u5c31\u662f\u4e00\u4e2a null\uff0c\u56e0\u4e3a\u67d0\u4e9b\u524d\u7aef\u9650\u5236\uff0c\u5f88\u96be\u5904\u7406 null\uff0c\u5b83\u4eec\u5e0c\u671b\u8fd9\u4e2a\u4e1c\u897f\u81f3\u5c11\u5e8f\u5217\u5316\u662f\u4e2a {} <\/p><\/div>\n<\/p><\/div>\n<\/li>\n

  • \n
    \n
    \n
    \u8cc7\u6df1\u5927\u4f6c : palmers <\/span> <\/div>\n
    <\/i> <\/span> <\/div>\n<\/p><\/div>\n
    \u6709\u521d\u59cb\u503c \u4e0d\u5c31\u6709\u7c7b\u578b\u4e86\u5417\uff1f <\/div>\n<\/p><\/div>\n<\/li>\n
  • \n
    \n
    \n
    \u8cc7\u6df1\u5927\u4f6c : sydra <\/span> <\/div>\n
    <\/i> <\/span> <\/div>\n<\/p><\/div>\n
    @abcbuzhiming \u5728\u53cd\u5e8f\u5217\u5316\u7684\u63a5\u53e3\u91cc\u9762\u589e\u52a0\u4e00\u4e2a\u7a7a\u5224\u65ad\u5c31\u53ef\u4ee5\u4e86 <\/div>\n<\/p><\/div>\n<\/li>\n
  • \n
    \n
    \n
    \u8cc7\u6df1\u5927\u4f6c : Elroooo0Y <\/span> <\/div>\n
    <\/i> <\/span> <\/div>\n<\/p><\/div>\n
    @abcbuzhiming
    \u8fd9\u5f88\u7b80\u5355\u554a \u91cd\u5199 getResult \u65b9\u6cd5 \u8fd4\u56de\u4e00\u4e2a\u7a7a\u5bf9\u8c61 <\/div>\n<\/p><\/div>\n<\/li>\n
  • \n
    \n
    \n
    \u8cc7\u6df1\u5927\u4f6c : LGA1150 <\/span> <\/div>\n
    <\/i> <\/span> <\/div>\n<\/p><\/div>\n
    \u5178\u578b\u7684 XY \u95ee\u9898 <\/div>\n<\/p><\/div>\n<\/li>\n
  • \n","protected":false},"excerpt":{"rendered":"

    Java \u5c31\u5b8c\u5168\u6ca1\u6709\u529e\u6cd5\u7ed9\u6cdb\u578b\u5c5e\u6027…<\/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\/325297"}],"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=325297"}],"version-history":[{"count":0,"href":"http:\/\/4563.org\/index.php?rest_route=\/wp\/v2\/posts\/325297\/revisions"}],"wp:attachment":[{"href":"http:\/\/4563.org\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=325297"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/4563.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=325297"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/4563.org\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=325297"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}