{"id":99,"date":"2020-03-05T01:09:31","date_gmt":"2020-03-04T17:09:31","guid":{"rendered":"https:\/\/blog.frost-s.tk\/?p=99"},"modified":"2020-03-13T18:25:47","modified_gmt":"2020-03-13T10:25:47","slug":"java-%e9%9d%a2%e8%af%95%e6%95%b4%e7%90%86","status":"publish","type":"post","link":"https:\/\/blog.frost-s.com\/index.php\/2020\/03\/05\/java-%e9%9d%a2%e8%af%95%e6%95%b4%e7%90%86\/","title":{"rendered":"Java \u9762\u8bd5\u6574\u7406"},"content":{"rendered":"\n

\u4e00\u3001java\u57fa\u7840\u77e5\u8bc6\u56de\u987e<\/h2>\n\n\n\n

1\u3001java\u4e2d\u7684\u51e0\u79cd\u57fa\u672c\u7c7b\u578b\uff0c\u5404\u5360\u7528\u591a\u5c11\u5b57\u8282\uff1f<\/strong><\/p>\n\n\n\n

Boolean \uff1a1\u5b57\u8282 byte\uff1a1\u5b57\u8282 short\uff1a2\u5b57\u8282 int\uff1a4\u5b57\u8282 long\uff1a 8\u5b57\u8282 char\uff1a2\u5b57\u8282 float\uff1a4\u5b57\u8282 double\uff1a8\u5b57\u8282<\/p>\n\n\n\n

\"\"<\/div><\/a><\/figure>\n\n\n\n

2\u3001string\u53ef\u4ee5\u88ab\u7ee7\u627f\u4e48\uff0c\u4e3a\u4ec0\u4e48\uff1f<\/strong><\/p>\n\n\n\n

\u4e0d\u53ef\u4ee5\uff0c\u56e0\u4e3astring\u662ffinal\u4fee\u9970\u7684\uff0c\u800cfinal\u4fee\u9970\u7684\u7c7b\u662f\u4e0d\u80fd\u88ab\u7ee7\u627f\u7684\uff0c\u5b9e\u73b0\u7ec6\u8282\u4e0d\u5141\u8bb8\u6539\u53d8\uff0c\u5728\u6e90\u7801\u4e2dString str=\"a\" ,\u548cString str=new String\uff08\"a\"\uff09\u5728\u6e90\u7801\u91cc\u7684\u8c03\u7528\u662f\u4e0d\u540c\u7684\uff1a<\/p>\n\n\n\n

\u524d\u8005\u8c03\u7528\u7684<\/p>\n\n\n\n

public static String valueOf(int i) {\n\treturn Integer.toString(i);\n}<\/pre>\n\n\n\n
\u540e\u8005\u8c03\u7528\u7684\u662f<\/p>\n\n\n\n
public String(String original) {\n\tthis.value = original.value;\n\tthis.hash = original.hash;\n}<\/pre>\n\n\n\n
\u6700\u540e\u5b58\u50a8\u5728final \u4fee\u9970\u7684char[]\u6570\u7ec4\u4e2d<\/p>\n\n\n\n
3\u3001string \uff0cstringbuffer\uff0cstringbuilder \u7684\u533a\u522b<\/strong><\/p>\n\n\n\n
String \u5b57\u7b26\u4e32\u5e38\u91cf(final\u4fee\u9970\uff0c\u4e0d\u53ef\u88ab\u7ee7\u627f)\uff0cString\u662f\u5e38\u91cf\uff0c\u5f53\u521b\u5efa\u4e4b\u540e\u5373\u4e0d\u80fd\u66f4\u6539\u3002(\u53ef\u4ee5\u901a\u8fc7StringBuffer\u548cStringBuilder\u521b\u5efaString\u5bf9\u8c61(\u5e38\u7528\u7684\u4e24\u4e2a\u5b57\u7b26\u4e32\u64cd\u4f5c\u7c7b)\u3002)
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 StringBuilder \u5b57\u7b26\u4e32\u53d8\u91cf\uff08\u975e\u7ebf\u7a0b\u5b89\u5168\uff09\u5176\u81eajdk1.5\u8d77\u5f00\u59cb\u51fa\u73b0\u3002\u4e0eStringBuffer\u4e00\u6837\u90fd\u7ee7\u627f\u548c\u5b9e\u73b0\u4e86\u540c\u6837\u7684\u63a5\u53e3\u548c\u7c7b\uff0c\u65b9\u6cd5\u9664\u4e86\u6ca1\u4f7f\u7528synch\u4fee\u9970\u4ee5\u5916\u57fa\u672c\u4e00\u81f4\uff0c\u4e0d\u540c\u4e4b\u5904\u5728\u4e8e\u6700\u540etoString\u7684\u65f6\u5019\uff0c\u4f1a\u76f4\u63a5\u8fd4\u56de\u4e00\u4e2a\u65b0\u5bf9\u8c61\u3002 <\/p>\n\n\n\n
4\u3001ArrayList \u548cLinkedlist\u7684\u533a\u522b<\/strong><\/p>\n\n\n\n
1.ArrayList\u662f\u57fa\u4e8e\u7d22\u5f15\u7684\u6570\u636e\u63a5\u53e3\uff0c\u5b83\u7684\u5e95\u5c42\u662f\u6570\u7ec4\u3002\u5b83\u53ef\u4ee5\u4ee5O(1)\u65f6\u95f4\u590d\u6742\u5ea6\u5bf9\u5143\u7d20\u8fdb\u884c\u968f\u673a\u8bbf\u95ee\u3002\u4e0e\u6b64\u5bf9\u5e94\uff0cLinkedList\u662f\u4ee5\u5143\u7d20\u5217\u8868\u7684\u5f62\u5f0f\u5b58\u50a8\u5b83\u7684\u6570\u636e\uff0c\u6bcf\u4e00\u4e2a\u5143\u7d20\u90fd\u548c\u5b83\u7684\u524d\u4e00\u4e2a\u548c\u540e\u4e00\u4e2a\u5143\u7d20\u94fe\u63a5\u5728\u4e00\u8d77\uff0c\u5728\u8fd9\u79cd\u60c5\u51b5\u4e0b\uff0c\u67e5\u627e\u67d0\u4e2a\u5143\u7d20\u7684\u65f6\u95f4\u590d\u6742\u5ea6\u662fO(n)\u3002
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5\u3001\u7c7b\u7684\u5b9e\u4f8b\u5316\u987a\u5e8f\uff0c\u6bd4\u5982\u7236\u7c7b\u9759\u6001\u6570\u636e\uff0c\u6784\u9020\u51fd\u6570\uff0c\u5b57\u6bb5\uff0c\u5b50\u7c7b\u9759\u6001\u6570\u636e\uff0c\u6784\u9020\u51fd\u6570\uff0c\u5b57\u6bb5\uff0c\u5f53\u5728new\u7684\u65f6\u5019\uff0c\u4ed6\u4eec\u7684\u6267\u884c\u987a\u5e8f\uff1f<\/strong><\/p>\n\n\n\n
\u7236\u7c7b\u9759\u6001\u6210\u5458\u548c\u9759\u6001\u4ee3\u7801\u5757->\u5b50\u7c7b\u9759\u6001\u6210\u5458\u548c\u9759\u6001\u4ee3\u7801\u5757->\u7236\u7c7b\u975e\u9759\u6001\u6210\u5458\u548c\u975e\u9759\u6001\u4ee3\u7801\u5757->\u7236\u7c7b\u6784\u9020\u65b9\u6cd5->\u5b50\u7c7b\u975e\u9759\u6001\u6210\u5458\u548c\u975e\u9759\u6001\u4ee3\u7801\u5757->\u5b50\u7c7b\u6784\u9020\u65b9\u6cd5 <\/p>\n\n\n\n
TestCode<\/p>\n\n\n\n
\/\/\u7236\u7c7b\npublic class A {\n\n    public static String a=printStr(\"\u7236\u7c7b\u7684\u9759\u6001\u53d8\u91cf\");\n    public String s = printStr(\"\u7236\u7c7b\u7684\u975e\u9759\u6001\u53d8\u91cf\");\n    static {\n        printStr(\"\u7236\u7c7b\u7684\u9759\u6001\u5757\");\n    }\n    {\n        printStr(\"\u7236\u7c7b\u7684\u975e\u9759\u6001\u5757\");\n    }\n    public A(){\n        printStr(\"\u7236\u7c7b\u6784\u9020\u65b9\u6cd5\");\n    }\n\n\n    public static String printStr(String str){\n        System.out.println(str);\n        return str;\n    }\n}<\/pre>\n\n\n\n
\/\/\u5b50\u7c7b\npublic class B extends A {\n\n    public static String b=printStr(\"\u5b50\u7c7b\u7684\u9759\u6001\u53d8\u91cf\");\n    public String st = printStr(\"\u5b50\u7c7b\u7684\u975e\u9759\u6001\u53d8\u91cf\");\n   \n    static {\n        printStr(\"\u5b50\u7c7b\u7684\u9759\u6001\u5757\");\n    }\n    {\n        printStr(\"\u5b50\u7c7b\u7684\u975e\u9759\u6001\u5757\");\n    }\n    public B(){\n        printStr(\"\u5b50\u7c7b\u7684\u6784\u9020\u65b9\u6cd5\");\n    }\n\n    \/\/main\n    public static void main(String[] args) {\n        new B();\n    }\n}<\/pre>\n\n\n\n
6\u3001\u7528\u8fc7\u54ea\u4e9bmap\u7c7b\uff0c\u90fd\u6709\u4ec0\u4e48\u533a\u522b\uff0chashmap\u662f\u7ebf\u7a0b\u5b89\u5168\u7684\u4e48\uff0c\u5e76\u53d1\u4e0b\u4f7f\u7528\u7684map\u662f\u4ec0\u4e48\uff0c\u4ed6\u4eec\u7684\u5185\u90e8\u5b9e\u73b0\u539f\u7406\u5206\u522b\u662f\u4ec0\u4e48\uff0c\u6bd4\u5982\u5b58\u50a8\u65b9\u5f0f\uff0chashcode\uff0c\u6269\u5bb9\uff0c\u9ed8\u8ba4\u5bb9\u91cf\u7b49\u3002<\/strong><\/p>\n\n\n\n
\u7b80\u8ff0\uff1a hashMap\u662f\u7ebf\u7a0b\u4e0d\u5b89\u5168\u7684\uff0cHashMap\u662f\u6570\u7ec4+\u94fe\u8868+\u7ea2\u9ed1\u6811\uff08JDK1.8\u589e\u52a0\u4e86\u7ea2\u9ed1\u6811\u90e8\u5206\uff09\u5b9e\u73b0\u7684\uff0c\u91c7\u7528\u54c8\u5e0c\u8868\u6765\u5b58\u50a8\u7684\u3002<\/p>\n\n\n\n
\u8be6\u7ec6\u8bb2\u89e3<\/a><\/div>\n\n\n\n
 ConcurrentHashMap <\/a><\/div>\n\n\n\n
7\u3001\u6709\u6ca1\u6709\u6709\u987a\u5e8f\u7684map\u5b9e\u73b0\u7c7b\uff0c\u5982\u679c\u6709\uff0c\u4ed6\u4eec\u662f\u600e\u4e48\u4fdd\u8bc1\u6709\u5e8f\u7684\uff1f<\/strong><\/p>\n\n\n\n
TreeMap\u548cLinkedHashMap\u662f\u6709\u5e8f\u7684\uff08TreeMap\u9ed8\u8ba4\u5347\u5e8f\uff0cLinkedHashMap\u5219\u8bb0\u5f55\u4e86\u63d2\u5165\u987a\u5e8f\uff09\u3002<\/p>\n\n\n\n
\u8be6\u7ec6\u8bb2\u89e3<\/a><\/div>\n\n\n\n
8\u3001\u62bd\u8c61\u7c7b\u548c\u63a5\u53e3\u7684\u533a\u522b\uff0c\u7c7b\u53ef\u4ee5\u7ee7\u627f\u591a\u4e2a\u7c7b\u4e48\uff0c\u63a5\u53e3\u5f00\u4e1a\u7ee7\u627f\u591a\u4e2a\u63a5\u53e3\u4e48\uff0c\u7c7b\u53ef\u4ee5\u5b9e\u73b0\u591a\u4e2a\u63a5\u53e3\u4e48\uff1f<\/strong><\/p>\n\n\n\n
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 7\u3001\u62bd\u8c61\u7c7b\u91cc\u53ef\u4ee5\u6ca1\u6709\u62bd\u8c61\u65b9\u6cd5
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9\u3001\u7ee7\u627f\u548c\u805a\u5408\u7684\u533a\u522b\u5728\u54ea\u91cc\uff1f<\/strong><\/p>\n\n\n\n
 \u7ee7\u627f\u6307\u7684\u662f\u4e00\u4e2a\u7c7b\uff08\u79f0\u4e3a\u5b50\u7c7b\u3001\u5b50\u63a5\u53e3\uff09\u7ee7\u627f\u53e6\u5916\u7684\u4e00\u4e2a\u7c7b\uff08\u79f0\u4e3a\u7236\u7c7b\u3001\u7236\u63a5\u53e3\uff09\u7684\u529f\u80fd\uff0c\u5e76\u53ef\u4ee5\u589e\u52a0\u5b83\u81ea\u5df1\u7684\u65b0\u529f\u80fd\u7684\u80fd\u529b\uff0c\u7ee7\u627f\u662f\u7c7b\u4e0e\u7c7b\u6216\u8005\u63a5\u53e3\u4e0e\u63a5\u53e3\u4e4b\u95f4\u6700\u5e38\u89c1\u7684\u5173\u7cfb\uff1b\u5728Java\u4e2d\u6b64\u7c7b\u5173\u7cfb\u901a\u8fc7\u5173\u952e\u5b57extends\u660e\u786e\u6807\u8bc6\uff0c\u5728\u8bbe\u8ba1\u65f6\u4e00\u822c\u6ca1\u6709\u4e89\u8bae\u6027\uff1b<\/p>\n\n\n\n
\u805a\u5408\u662f\u5173\u8054\u5173\u7cfb\u7684\u4e00\u79cd\u7279\u4f8b\uff0c\u4ed6\u4f53\u73b0\u7684\u662f\u6574\u4f53\u4e0e\u90e8\u5206\u3001\u62e5\u6709\u7684\u5173\u7cfb\uff0c\u5373has-a\u7684\u5173\u7cfb\uff0c\u6b64\u65f6\u6574\u4f53\u4e0e\u90e8\u5206\u4e4b\u95f4\u662f\u53ef\u5206\u79bb\u7684\uff0c\u4ed6\u4eec\u53ef\u4ee5\u5177\u6709\u5404\u81ea\u7684\u751f\u547d\u5468\u671f\uff0c\u90e8\u5206\u53ef\u4ee5\u5c5e\u4e8e\u591a\u4e2a\u6574\u4f53\u5bf9\u8c61\uff0c\u4e5f\u53ef\u4ee5\u4e3a\u591a\u4e2a\u6574\u4f53\u5bf9\u8c61\u5171\u4eab\uff1b\u6bd4\u5982\u8ba1\u7b97\u673a\u4e0eCPU\u3001\u516c\u53f8\u4e0e\u5458\u5de5\u7684\u5173\u7cfb\u7b49\uff1b\u8868\u73b0\u5728\u4ee3\u7801\u5c42\u9762\uff0c\u548c\u5173\u8054\u5173\u7cfb\u662f\u4e00\u81f4\u7684\uff0c\u53ea\u80fd\u4ece\u8bed\u4e49\u7ea7\u522b\u6765\u533a\u5206\uff1b<\/p>\n\n\n\n
10\u3001\u8bb2\u8bb2\u4f60\u7406\u89e3\u7684nio\u548cbio\u7684\u533a\u522b\u662f\u4ec0\u4e48\uff0c\u8c08\u8c08reactor\u7684\u6a21\u578b\u3002<\/strong><\/p>\n\n\n\n
IO(BIO)\u662f\u9762\u5411\u6d41\u7684\uff0cNIO\u662f\u9762\u5411\u7f13\u51b2\u533a\u7684
 BIO\uff1aBlock IO \u540c\u6b65\u963b\u585e\u5f0f IO\uff0c\u5c31\u662f\u6211\u4eec\u5e73\u5e38\u4f7f\u7528\u7684\u4f20\u7edf IO\uff0c\u5b83\u7684\u7279\u70b9\u662f\u6a21\u5f0f\u7b80\u5355\u4f7f\u7528\u65b9\u4fbf\uff0c\u5e76\u53d1\u5904\u7406\u80fd\u529b\u4f4e\u3002
 NIO\uff1aNew IO \u540c\u6b65\u975e\u963b\u585e IO\uff0c\u662f\u4f20\u7edf IO \u7684\u5347\u7ea7\uff0c\u5ba2\u6237\u7aef\u548c\u670d\u52a1\u5668\u7aef\u901a\u8fc7 Channel\uff08\u901a\u9053\uff09\u901a\u8baf\uff0c\u5b9e\u73b0\u4e86\u591a\u8def\u590d\u7528\u3002
 AIO\uff1aAsynchronous IO \u662f NIO \u7684\u5347\u7ea7\uff0c\u4e5f\u53eb NIO2\uff0c\u5b9e\u73b0\u4e86\u5f02\u6b65\u975e\u5835\u585e IO \uff0c\u5f02\u6b65 IO \u7684\u64cd\u4f5c\u57fa\u4e8e\u4e8b\u4ef6\u548c\u56de\u8c03\u673a\u5236\u3002<\/p>\n\n\n\n
\u8be6\u7ec6\u8bb2\u89e3<\/a><\/div>\n\n\n\n
\u8be6\u7ec6\u8bb2\u89e32<\/a><\/div>\n\n\n\n
11\u3001\u53cd\u5c04\u7684\u539f\u7406\uff0c\u53cd\u5c04\u521b\u5efa\u7c7b\u5b9e\u4f8b\u7684\u4e09\u79cd\u65b9\u5f0f<\/strong><\/p>\n\n\n\n
\u8be6\u7ec6\u8bb2\u89e3<\/a><\/div>\n\n\n\n
12\u3001\u53cd\u5c04\u4e2d\uff0cClass.forName \u548c ClassLoader\u7684\u533a\u522b\u3002<\/strong><\/p>\n\n\n\n
\u8be6\u7ec6\u8bb2\u89e3<\/a><\/div>\n\n\n\n
13\u3001\u63cf\u8ff0\u52a8\u6001\u4ee3\u7406\u7684\u51e0\u79cd\u5b9e\u73b0\u65b9\u5f0f\uff0c\u5206\u522b\u8bf4\u51fa\u76f8\u5e94\u7684\u4f18\u7f3a\u70b9\u3002 \u52a8\u6001\u4ee3\u7406\u4e0e cglib \u5b9e\u73b0\u7684\u533a\u522b <\/strong>\u3002<\/p>\n\n\n\n
Jdk cglib jdk\u5e95\u5c42\u662f\u5229\u7528\u53cd\u5c04\u673a\u5236\uff0c\u9700\u8981\u57fa\u4e8e\u63a5\u53e3\u65b9\u5f0f\uff0c\u8fd9\u662f\u7531\u4e8e<\/p>\n\n\n\n
Proxy.newProxyInstance(target.getClass().getClassLoader(),<br> target.getClass().getInterfaces(), this);<\/pre>\n\n\n\n

 Cglib\u5219\u662f\u57fa\u4e8easm\u6846\u67b6\uff0c\u5b9e\u73b0\u4e86\u65e0\u53cd\u5c04\u673a\u5236\u8fdb\u884c\u4ee3\u7406\uff0c\u5229\u7528\u7a7a\u95f4\u6765\u6362\u53d6\u4e86\u65f6\u95f4\uff0c\u4ee3\u7406\u6548\u7387\u9ad8\u4e8ejdk<\/p>\n\n\n\n
14\u3001\u4e3a\u4ec0\u4e48CGlib\u53ef\u4ee5\u5bf9\u63a5\u53e3\u5b9e\u73b0\u4ee3\u7406\u3002<\/strong><\/p>\n\n\n\n
\u8be6\u7ec6\u8bb2\u89e3<\/a><\/div>\n\n\n\n
15\u3001final\u7684\u7528\u9014<\/strong><\/p>\n\n\n\n
final \u4fee\u9970\u7684\u7c7b\u53eb\u6700\u7ec8\u7c7b\uff0c\u8be5\u7c7b\u4e0d\u80fd\u88ab\u7ee7\u627f\u3002
final \u4fee\u9970\u7684\u65b9\u6cd5\u4e0d\u80fd\u88ab\u91cd\u5199\u3002
final \u4fee\u9970\u7684\u53d8\u91cf\u53eb\u5e38\u91cf\uff0c\u5e38\u91cf\u5fc5\u987b\u521d\u59cb\u5316\uff0c\u521d\u59cb\u5316\u4e4b\u540e\u503c\u5c31\u4e0d\u80fd\u88ab\u4fee\u6539\u3002 <\/p>\n\n\n\n
16\u3001\u5199\u51fa\u4e09\u79cd\u5355\u4f8b\u6a21\u5f0f\u7684\u5b9e\u73b0<\/strong><\/p>\n\n\n\n
 \u61d2\u6c49\u5f0f\u5355\u4f8b\uff1a<\/p>\n\n\n\n
public class Singleton {\n    private static Singleton instance;\n    private Singleton (){}\n\n    public static synchronized Singleton getInstance() {\n\tif (instance == null) {\n\t    instance = new Singleton();\n\t}\n\treturn instance;\n    }\n}<\/pre>\n\n\n\n
\u997f\u6c49\u5f0f\u5355\u4f8b\uff1a<\/p>\n\n\n\n
public class Singleton {  \n    private static Singleton instance = new Singleton();  \n    private Singleton (){}  \n    public static Singleton getInstance() {  \n    return instance;  \n    }  \n}<\/pre>\n\n\n\n
\u9759\u6001\u5185\u90e8\u7c7b\uff1a<\/p>\n\n\n\n
public class Singleton {  \n    private static class SingletonHolder {  \n    private static final Singleton INSTANCE = new Singleton();  \n    }  \n    private Singleton (){}  \n    public static final Singleton getInstance() {  \n    return SingletonHolder.INSTANCE;  \n    }  \n} <\/pre>\n\n\n\n
  \u679a\u4e3e\uff1a<\/p>\n\n\n\n
public enum Singleton {\n    INSTANCE;\n    public void whateverMethod() {\n    }\n}<\/pre>\n\n\n\n
  \u53cc\u91cd\u6821\u9a8c\u9501\uff1a<\/p>\n\n\n\n
public class Singleton {\n    private volatile static Singleton singleton;\n    private Singleton (){}\n    public static Singleton getSingleton() {\n\tif (singleton == null) {\n\t    synchronized (Singleton.class) {\n\t\tif (singleton == null) {\n\t\t    singleton = new Singleton();\n\t\t}\n\t    }\n\t}\n\treturn singleton;\n    }\n}<\/pre>\n\n\n\n
17\u3001\u5982\u4f55\u5728\u7236\u7c7b\u4e3a\u5b50\u7c7b\u81ea\u52a8\u5b8c\u6210\u6240\u6709\u7684hashcode \u548cequals\u5b9e\u73b0\uff1f\u8fd9\u4e48\u505a\u6709\u4ec0\u4e48\u4f18\u52a3\uff1f<\/strong><\/p>\n\n\n\n
 \u540c\u65f6\u590d\u5199hashcode\u548cequals\u65b9\u6cd5\uff0c\u4f18\u52bf\u53ef\u4ee5\u6dfb\u52a0\u81ea\u5b9a\u4e49\u903b\u8f91\uff0c\u4e14\u4e0d\u5fc5\u8c03\u7528\u8d85\u7c7b\u7684\u5b9e\u73b0\u3002 <\/p>\n\n\n\n
\u8be6\u7ec6\u8bb2\u89e3<\/a><\/div>\n\n\n\n
18\u3001\u7ed3\u5408oo\u7684\u8bbe\u8ba1\u7406\u5ff5\uff0c\u8c08\u8c08\u8bbf\u95ee\u4fee\u9970\u7b26public \u3001private \u3001 default \u7684\u5e94\u7528\u8bbe\u8ba1\u4e2d\u7684\u4f5c\u7528\uff1f<\/strong><\/p>\n\n\n\n
\u8bbf\u95ee\u7b26\u4fee\u9970\uff0c\u4e3b\u8981\u6807\u8bc6\u4fee\u9970\u5757\u7684\u4f5c\u7528\u57df\uff0c\u65b9\u4fbf\u9694\u79bb\u9632\u62a4\u3002<\/p>\n\n\n\n
\u4f5c\u7528\u57df<\/td>\u5f53\u524d\u7c7b<\/td>\u540c\u4e00package<\/td>\u5b50\u5b59\u7c7b<\/td>\u5176\u4ed6package<\/td><\/tr>
public<\/td>\u221a<\/td>\u221a<\/td>\u221a<\/td>\u221a<\/td><\/tr>
protected<\/td>\u221a<\/td>\u221a<\/td>\u221a<\/td>\u00d7<\/td><\/tr>
default<\/td>\u221a<\/td>\u221a<\/td>\u00d7<\/td>\u00d7<\/td><\/tr>
private<\/td>\u221a<\/td>\u00d7<\/td>\u00d7<\/td>\u00d7<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n
public\uff1a Java\u8bed\u8a00\u4e2d\u8bbf\u95ee\u9650\u5236\u6700\u5bbd\u7684\u4fee\u9970\u7b26\uff0c\u4e00\u822c\u79f0\u4e4b\u4e3a\u201c\u516c\u5171\u7684\u201d\u3002\u88ab\u5176\u4fee\u9970\u7684\u7c7b\u3001\u5c5e\u6027\u4ee5\u53ca\u65b9\u6cd5\u4e0d\u4ec5\u53ef\u4ee5\u8de8\u7c7b\u8bbf\u95ee\uff0c\u800c\u4e14\u5141\u8bb8\u8de8\u5305\uff08package\uff09\u8bbf\u95ee\u3002
 private: Java\u8bed\u8a00\u4e2d\u5bf9\u8bbf\u95ee\u6743\u9650\u9650\u5236\u7684\u6700\u7a84\u7684\u4fee\u9970\u7b26\uff0c\u4e00\u822c\u79f0\u4e4b\u4e3a\u201c\u79c1\u6709\u7684\u201d\u3002\u88ab\u5176\u4fee\u9970\u7684\u7c7b\u3001\u5c5e\u6027\u4ee5\u53ca\u65b9\u6cd5\u53ea\u80fd\u88ab\u8be5\u7c7b\u7684\u5bf9\u8c61\u8bbf\u95ee\uff0c\u5176\u5b50\u7c7b\u4e0d\u80fd\u8bbf\u95ee\uff0c\u66f4\u4e0d\u80fd\u5141\u8bb8\u8de8\u5305\u8bbf\u95ee\u3002
 protect: \u4ecb\u4e8epublic \u548c private \u4e4b\u95f4\u7684\u4e00\u79cd\u8bbf\u95ee\u4fee\u9970\u7b26\uff0c\u4e00\u822c\u79f0\u4e4b\u4e3a\u201c\u4fdd\u62a4\u5f62\u201d\u3002\u88ab\u5176\u4fee\u9970\u7684\u7c7b\u3001\u5c5e\u6027\u4ee5\u53ca\u65b9\u6cd5\u53ea\u80fd\u88ab\u7c7b\u672c\u8eab\u7684\u65b9\u6cd5\u53ca\u5b50\u7c7b\u8bbf\u95ee\uff0c\u5373\u4f7f\u5b50\u7c7b\u5728\u4e0d\u540c\u7684\u5305\u4e2d\u4e5f\u53ef\u4ee5\u8bbf\u95ee\u3002
 default\uff1a\u5373\u4e0d\u52a0\u4efb\u4f55\u8bbf\u95ee\u4fee\u9970\u7b26\uff0c\u901a\u5e38\u79f0\u4e3a\"\u9ed8\u8ba4\u8bbf\u95ee\u6a21\u5f0f\"\u3002\u8be5\u6a21\u5f0f\u4e0b\uff0c\u53ea\u5141\u8bb8\u5728\u540c\u4e00\u4e2a\u5305\u4e2d\u8fdb\u884c\u8bbf\u95ee\u3002<\/p>\n\n\n\n
19\u3001\u6df1\u62f7\u8d1d\u548c\u6d45\u62f7\u8d1d\u7684\u533a\u522b<\/strong><\/p>\n\n\n\n
\u8be6\u7ec6\u8bb2\u89e3<\/a><\/div>\n\n\n\n
20\u3001\u6570\u7ec4\u548c\u94fe\u8868\u6570\u636e\u7ed3\u6784\u63cf\u8ff0\uff0c\u5404\u81ea\u7684\u65f6\u95f4\u590d\u6742\u5ea6\u3002<\/strong><\/p>\n\n\n\n
\u8be6\u7ec6\u8bb2\u89e3<\/a><\/div>\n\n\n\n
21\u3001error \u548cexception\u7684\u533a\u522b\uff0cCheckedException \uff0cRuntimeException\u7684\u533a\u522b<\/strong>\u3002<\/p>\n\n\n\n
\u8be6\u7ec6\u8bb2\u89e3<\/a><\/div>\n\n\n\n
22\u3001\u8bf7\u5217\u51fa\u4e94\u4e2a\u8fd0\u884c\u65f6\u5f02\u5e38\u3002<\/p>\n\n\n\n
23\u3001\u5728\u81ea\u5df1\u7684\u4ee3\u7801\u4e2d\uff0c\u5982\u679c\u521b\u5efa\u4e00\u4e2a java.lang.String \u5bf9\u8c61\uff0c\u8fd9\u4e2a\u5bf9\u8c61\u662f\u5426\u53ef\u4ee5\u88ab\u7c7b\u52a0\u8f7d\u5668\u52a0\u8f7d\uff1f\u4e3a\u4ec0\u4e48<\/p>\n\n\n\n
24\u3001\u8bf4\u4e00\u8bf4\u4f60\u5bf9 java.lang.Object \u5bf9\u8c61\u4e2d hashCode \u548c equals \u65b9\u6cd5\u7684\u7406\u89e3\u3002\u5728\u4ec0\u4e48\u573a\u666f\u4e0b\u9700\u8981\u91cd\u65b0\u5b9e\u73b0\u8fd9\u4e24\u4e2a\u65b9\u6cd5\u3002<\/p>\n\n\n\n
25\u3001\u5728 jdk1.5 \u4e2d\uff0c\u5f15\u5165\u4e86\u6cdb\u578b\uff0c\u6cdb\u578b\u7684\u5b58\u5728\u662f\u7528\u6765\u89e3\u51b3\u4ec0\u4e48\u95ee\u9898\u3002<\/p>\n\n\n\n
26\u3001\u8fd9\u6837\u7684 a.hashcode() \u6709\u4ec0\u4e48\u7528\uff0c\u4e0e a.equals(b)\u6709\u4ec0\u4e48\u5173\u7cfb\u3002<\/p>\n\n\n\n
27\u3001\u6709\u6ca1\u6709\u53ef\u80fd 2 \u4e2a\u4e0d\u76f8\u7b49\u7684\u5bf9\u8c61\u6709\u76f8\u540c\u7684 hashcode\u3002<\/p>\n\n\n\n
28\u3001Java \u4e2d\u7684 HashSet \u5185\u90e8\u662f\u5982\u4f55\u5de5\u4f5c\u7684\u3002<\/p>\n\n\n\n
29\u3001\u4ec0\u4e48\u662f\u5e8f\u5217\u5316\uff0c\u600e\u4e48\u5e8f\u5217\u5316\uff0c\u4e3a\u4ec0\u4e48\u5e8f\u5217\u5316\uff0c\u53cd\u5e8f\u5217\u5316\u4f1a\u9047\u5230\u4ec0\u4e48\u95ee\u9898\uff0c\u5982\u4f55\u89e3\u51b3\u3002<\/p>\n\n\n\n
30\u3001 java \u4e2d\u7684 Math.round(-1.5) \u7b49\u4e8e\u591a\u5c11\uff1f<\/p>\n\n\n\n
31\u3001 java \u4e2d IO \u6d41\u5206\u4e3a\u51e0\u79cd\uff1f\uff08\u529f\u80fd\u548c\u7c7b\u578b\u533a\u5206\uff09<\/p>\n\n\n\n
32\u3001Files\u7684\u5e38\u7528\u65b9\u6cd5\u6709\u54ea\u4e9b\uff1f<\/p>\n\n\n\n
33\u3001List\u3001Set\u3001Map\u7684\u533a\u522b\u662f\u4ec0\u4e48\uff1f<\/strong><\/p>\n\n\n\n
List\uff1a<\/p>\n\n\n\n
List\u7684\u5143\u7d20\u4ee5\u7ebf\u6027\u65b9\u5f0f\u5b58\u50a8\uff0c\u53ef\u4ee5\u5b58\u653e\u91cd\u590d\u5bf9\u8c61\uff0cList\u4e3b\u8981\u6709\u4ee5\u4e0b\u4e24\u4e2a\u5b9e\u73b0\u7c7b\uff1a<\/p>\n\n\n\n
ArrayList : \u957f\u5ea6\u53ef\u53d8\u7684\u6570\u7ec4\uff0c\u53ef\u4ee5\u5bf9\u5143\u7d20\u8fdb\u884c\u968f\u673a\u7684\u8bbf\u95ee\uff0c\u5411ArrayList\u4e2d\u63d2\u5165\u4e0e\u5220\u9664\u5143\u7d20\u7684\u901f\u5ea6\u6162\u3002 JDK8 \u4e2dArrayList\u6269\u5bb9\u7684\u5b9e\u73b0\u662f\u901a\u8fc7grow()\u65b9\u6cd5\u91cc\u4f7f\u7528\u8bed\u53e5newCapacity = oldCapacity + (oldCapacity >> 1)\uff08\u53731.5\u500d\u6269\u5bb9\uff09\u8ba1\u7b97\u5bb9\u91cf\uff0c\u7136\u540e\u8c03\u7528Arrays.copyof()\u65b9\u6cd5\u8fdb\u884c\u5bf9\u539f\u6570\u7ec4\u8fdb\u884c\u590d\u5236\u3002
 <\/p>\n\n\n\n
LinkedList: \u91c7\u7528\u94fe\u8868\u6570\u636e\u7ed3\u6784\uff0c\u63d2\u5165\u548c\u5220\u9664\u901f\u5ea6\u5feb\uff0c\u4f46\u8bbf\u95ee\u901f\u5ea6\u6162\u3002<\/p>\n\n\n\n
Set\uff1a<\/p>\n\n\n\n
Set\u4e2d\u7684\u5bf9\u8c61\u4e0d\u6309\u7279\u5b9a(HashCode)\u7684\u65b9\u5f0f\u6392\u5e8f\uff0c\u5e76\u4e14\u6ca1\u6709\u91cd\u590d\u5bf9\u8c61\uff0cSet\u4e3b\u8981\u6709\u4ee5\u4e0b\u4e24\u4e2a\u5b9e\u73b0\u7c7b\uff1a<\/p>\n\n\n\n
HashSet\uff1a HashSet\u6309\u7167\u54c8\u5e0c\u7b97\u6cd5\u6765\u5b58\u53d6\u96c6\u5408\u4e2d\u7684\u5bf9\u8c61\uff0c\u5b58\u53d6\u901f\u5ea6\u6bd4\u8f83\u5feb\u3002\u5f53HashSet\u4e2d\u7684\u5143\u7d20\u4e2a\u6570\u8d85\u8fc7\u6570\u7ec4\u5927\u5c0f*loadFactor\uff08\u9ed8\u8ba4\u503c\u4e3a0.75\uff09\u65f6\uff0c\u5c31\u4f1a\u8fdb\u884c\u8fd1\u4f3c\u4e24\u500d\u6269\u5bb9\uff08newCapacity = (oldCapacity << 1) + 1\uff09\u3002<\/p>\n\n\n\n
TreeSet \uff1aTreeSet\u5b9e\u73b0\u4e86SortedSet\u63a5\u53e3\uff0c\u80fd\u591f\u5bf9\u96c6\u5408\u4e2d\u7684\u5bf9\u8c61\u8fdb\u884c\u6392\u5e8f\u3002<\/p>\n\n\n\n
Map\uff1a<\/p>\n\n\n\n
Map\u662f\u4e00\u79cd\u628a\u952e\u5bf9\u8c61\u548c\u503c\u5bf9\u8c61\u6620\u5c04\u7684\u96c6\u5408\uff0c\u5b83\u7684\u6bcf\u4e00\u4e2a\u5143\u7d20\u90fd\u5305\u542b\u4e00\u4e2a\u952e\u5bf9\u8c61\u548c\u503c\u5bf9\u8c61\u3002 Map\u4e3b\u8981\u6709\u4ee5\u4e0b\u4e24\u4e2a\u5b9e\u73b0\u7c7b\uff1a<\/p>\n\n\n\n
HashMap\uff1aHashMap\u57fa\u4e8e\u6563\u5217\u8868\u5b9e\u73b0\uff0c\u5176\u63d2\u5165\u548c\u67e5\u8be2\u7684\u5f00\u9500\u662f\u56fa\u5b9a\u7684\uff0c\u53ef\u4ee5\u901a\u8fc7\u6784\u9020\u5668\u8bbe\u7f6e\u5bb9\u91cf\u548c\u8d1f\u8f7d\u56e0\u5b50\u6765\u8c03\u6574\u5bb9\u5668\u7684\u6027\u80fd\u3002<\/p>\n\n\n\n
LinkedHashMap\uff1a\u7c7b\u4f3c\u4e8eHashMap\uff0c\u4f46\u662f\u8fed\u4ee3\u904d\u5386\u5b83\u65f6\uff0c\u53d6\u5f97\u7684\u987a\u5e8f\u662f\u5176\u63d2\u5165\u6b21\u5e8f\uff0c\u6216\u8005\u662f\u6700\u8fd1\u6700\u5c11\u4f7f\u7528(LRU)\u7684\u6b21\u5e8f\u3002<\/p>\n\n\n\n
TreeMap\uff1aTreeMap\u57fa\u4e8e\u7ea2\u9ed1\u6811\u5b9e\u73b0\u3002\u67e5\u770b\u65f6\uff0c\u5b83\u4eec\u4f1a\u88ab\u6392\u5e8f\u3002TreeMap\u662f\u552f\u4e00\u7684\u5e26\u6709subMap()\u65b9\u6cd5\u7684Map\uff0csubMap()\u53ef\u4ee5\u8fd4\u56de\u4e00\u4e2a\u5b50\u6811\u3002<\/p>\n\n\n\n
\"\"<\/div><\/a><\/figure>\n\n\n\n
34\u3001<\/p>\n","protected":false},"excerpt":{"rendered":"
\u4e00\u3001java\u57fa\u7840\u77e5\u8bc6\u56de\u987e 1\u3001java\u4e2d\u7684\u51e0\u79cd\u57fa\u672c\u7c7b\u578b\uff0c\u5404\u5360\u7528\u591a\u5c11\u5b57\u8282\uff1f Boolean \uff1a1\u5b57\u8282 byte\uff1a […]<\/p>\n","protected":false},"author":1,"featured_media":42,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[10],"tags":[],"_links":{"self":[{"href":"https:\/\/blog.frost-s.com\/index.php\/wp-json\/wp\/v2\/posts\/99"}],"collection":[{"href":"https:\/\/blog.frost-s.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blog.frost-s.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blog.frost-s.com\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/blog.frost-s.com\/index.php\/wp-json\/wp\/v2\/comments?post=99"}],"version-history":[{"count":23,"href":"https:\/\/blog.frost-s.com\/index.php\/wp-json\/wp\/v2\/posts\/99\/revisions"}],"predecessor-version":[{"id":231,"href":"https:\/\/blog.frost-s.com\/index.php\/wp-json\/wp\/v2\/posts\/99\/revisions\/231"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/blog.frost-s.com\/index.php\/wp-json\/wp\/v2\/media\/42"}],"wp:attachment":[{"href":"https:\/\/blog.frost-s.com\/index.php\/wp-json\/wp\/v2\/media?parent=99"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blog.frost-s.com\/index.php\/wp-json\/wp\/v2\/categories?post=99"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blog.frost-s.com\/index.php\/wp-json\/wp\/v2\/tags?post=99"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}