{"id":211,"date":"2026-07-14T20:30:00","date_gmt":"2026-07-14T12:30:00","guid":{"rendered":"http:\/\/ssjava.xyz\/?p=211"},"modified":"2026-07-14T21:00:14","modified_gmt":"2026-07-14T13:00:14","slug":"02-%e5%8f%98%e9%87%8f%e4%b8%8e%e6%95%b0%e6%8d%ae%e7%b1%bb%e5%9e%8b%ef%bc%9ajava-%e7%9a%84-8-%e7%a7%8d%e5%9f%ba%e6%9c%ac%e7%b1%bb%e5%9e%8b%e8%af%a6%e8%a7%a3","status":"publish","type":"post","link":"https:\/\/ssjava.xyz\/index.php\/2026\/07\/14\/02-%e5%8f%98%e9%87%8f%e4%b8%8e%e6%95%b0%e6%8d%ae%e7%b1%bb%e5%9e%8b%ef%bc%9ajava-%e7%9a%84-8-%e7%a7%8d%e5%9f%ba%e6%9c%ac%e7%b1%bb%e5%9e%8b%e8%af%a6%e8%a7%a3\/","title":{"rendered":"02. \u53d8\u91cf\u4e0e\u6570\u636e\u7c7b\u578b\uff1aJava \u7684 8 \u79cd\u57fa\u672c\u7c7b\u578b\u8be6\u89e3"},"content":{"rendered":"\n

\u4ece HelloWorld \u5230\u771f\u6b63\u5199\u51fa\u6709\u7528\u7684\u7a0b\u5e8f\uff0c\u4f60\u9047\u5230\u7684\u7b2c\u4e00\u4e2a\u5c94\u8def\u53e3\u5c31\u662f\uff1a\u6570\u636e\u600e\u4e48\u5b58\uff0c\u53d8\u91cf\u600e\u4e48\u7528\u3002\u7c7b\u578b\u58f0\u660e\u3001\u8d4b\u503c\u3001\u547d\u540d\u89c4\u8303\uff0c\u8fd9\u4e9b\u770b\u4f3c\u57fa\u7840\u7684\u4e1c\u897f\uff0c\u6070\u6070\u662f\u5199\u51fa\u6574\u6d01\u4ee3\u7801\u7684\u8d77\u70b9\u2014\u2014\u5f88\u591a\u8001\u624b\u8e29\u8fc7\u7684\u5751\uff0c\u6e90\u5934\u90fd\u5728\u8fd9\u91cc\u3002<\/p>\n\n\n\n

\u4e00\u3001\u53d8\u91cf\uff1a\u5185\u5b58\u4e2d\u7684”\u4fbf\u7b7e\u76d2”<\/h2>\n\n\n\n

\u5982\u679c\u628a\u8ba1\u7b97\u673a\u5185\u5b58\u60f3\u8c61\u6210\u4e00\u4e2a\u5de8\u5927\u7684\u50a8\u7269\u67dc\uff0c\u53d8\u91cf\u5c31\u662f\u67dc\u95e8\u4e0a\u8d34\u4e86\u6807\u7b7e\u7684\u76d2\u5b50\u2014\u2014\u6807\u7b7e\u662f\u53d8\u91cf\u540d\uff0c\u76d2\u5b50\u91cc\u88c5\u7684\u662f\u6570\u636e\u3002\u4f60\u53ef\u4ee5\u6253\u5f00\u76d2\u5b50\u770b\u91cc\u9762\u7684\u6570\u636e\uff0c\u4e5f\u53ef\u4ee5\u6362\u6389\u5b83\u3002<\/p>\n\n\n\n

\u521b\u5efa\u4e00\u4e2a\u53d8\u91cf\u9700\u8981\u4e24\u6b65\uff1a<\/p>\n\n\n\n

    \n
  1. \u58f0\u660e<\/strong>\uff1a\u544a\u8bc9 Java \u8fd9\u4e2a\u53d8\u91cf\u53eb\u4ec0\u4e48\u540d\u5b57\u3001\u88c5\u4ec0\u4e48\u7c7b\u578b\u7684\u6570\u636e<\/li>\n
  2. \u8d4b\u503c<\/strong>\uff1a\u5f80\u76d2\u5b50\u91cc\u653e\u6570\u636e<\/li>\n<\/ol>\n\n\n\n
    \/\/ \u58f0\u660e\u4e00\u4e2a\u6574\u578b\u53d8\u91cf age\nint age;\n\n\/\/ \u7ed9 age \u8d4b\u503c\nage = 25;\n\n\/\/ \u4e5f\u53ef\u4ee5\u5728\u58f0\u660e\u7684\u540c\u65f6\u76f4\u63a5\u8d4b\u503c\uff08\u521d\u59cb\u5316\uff09\nint score = 88;<\/code><\/pre>\n\n\n\n
    \u53d8\u91cf\u547d\u540d\u89c4\u5219\uff08\u8bb0\u7262\uff0c\u7f16\u8bd1\u671f\u4f1a\u68c0\u67e5\uff09\uff1a<\/strong><\/p>\n\n\n\n
      \n
    • \u53ea\u80fd\u5305\u542b\uff1a\u5b57\u6bcd\u3001\u6570\u5b57\u3001\u4e0b\u5212\u7ebf _<\/code>\u3001\u7f8e\u5143\u7b26\u53f7 $<\/code><\/li>\n
    • \u4e0d\u80fd\u4ee5\u6570\u5b57\u5f00\u5934<\/li>\n
    • \u4e0d\u80fd\u662f Java \u5173\u952e\u5b57\uff08\u5982 int<\/code>\u3001class<\/code>\u3001public<\/code>\uff09<\/li>\n
    • \u5927\u5c0f\u5199\u654f\u611f\uff08age<\/code> \u548c Age<\/code> \u662f\u4e24\u4e2a\u4e0d\u540c\u7684\u53d8\u91cf\uff09<\/li>\n
    • \u9a7c\u5cf0\u547d\u540d\u6cd5<\/strong>\uff1a\u9996\u5b57\u6bcd\u5c0f\u5199\uff0c\u540e\u9762\u6bcf\u4e2a\u5355\u8bcd\u9996\u5b57\u6bcd\u5927\u5199\uff0c\u5982 studentName<\/code>\u3001totalScore<\/code><\/li>\n<\/ul>\n\n\n\n
      \u4e8c\u3001Java \u7684 8 \u79cd\u57fa\u672c\u6570\u636e\u7c7b\u578b<\/h2>\n\n\n\n
      Java \u7684\u6570\u636e\u7c7b\u578b\u5206\u4e24\u5927\u7c7b\uff1a\u57fa\u672c\u7c7b\u578b<\/strong>\uff08primitive types\uff09\u548c\u5f15\u7528\u7c7b\u578b<\/strong>\uff08reference types\uff09\u3002\u5148\u770b\u57fa\u672c\u7c7b\u578b\uff0c\u5171 8 \u79cd\uff1a<\/p>\n\n\n\n
      2.1 \u6574\u6570\u7c7b\u578b\uff084 \u79cd\uff09<\/h3>\n\n\n\n
      \u7c7b\u578b<\/th>\u5360\u7528<\/th>\u53d6\u503c\u8303\u56f4<\/th>\u9ed8\u8ba4\u503c<\/th><\/tr><\/thead>
      byte<\/code><\/td>1 \u5b57\u8282<\/td>-128 ~ 127<\/td>0<\/td><\/tr>
      short<\/code><\/td>2 \u5b57\u8282<\/td>-32,768 ~ 32,767<\/td>0<\/td><\/tr>
      int<\/code><\/td>4 \u5b57\u8282<\/td>-2\u00b3\u00b9 ~ 2\u00b3\u00b9-1\uff08\u7ea6 \u00b121\u4ebf\uff09<\/td>0<\/td><\/tr>
      long<\/code><\/td>8 \u5b57\u8282<\/td>-2\u2076\u00b3 ~ 2\u2076\u00b3-1<\/td>0L<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n
      byte b = 100;           \/\/ byte\uff1a\u7701\u5185\u5b58\uff0c\u5e38\u7528\u4e8e\u6587\u4ef6\u6d41\u3001\u7f51\u7edc\u4f20\u8f93\nshort s = 20000;        \/\/ short\uff1a\u4e0d\u592a\u5e38\u7528\nint count = 999999;     \/\/ int\uff1a\u65e5\u5e38\u6700\u5e38\u7528\uff01\nlong big = 3000000000L; \/\/ long\uff1a\u6ce8\u610f\u6570\u5b57\u672b\u5c3e\u52a0 L\uff08\u5927\u5c0f\u5199\u90fd\u884c\uff0c\u63a8\u8350\u5927\u5199\u907f\u514d\u6df7\u6dc6\uff09<\/code><\/pre>\n\n\n\n
      \u9762\u8bd5\u9ad8\u9891\u9898\uff1a<\/strong><\/p>\n\n\n\n
      long big = 3000000000;   \/\/ \u7f16\u8bd1\u62a5\u9519\uff01\u6570\u5b57 3000000000 \u8d85\u8fc7\u4e86 int \u8303\u56f4\nlong big2 = 3000000000L; \/\/ \u2705 \u6b63\u786e\uff0c\u52a0 L \u544a\u8bc9\u7f16\u8bd1\u5668\u8fd9\u662f long \u5b57\u9762\u91cf<\/code><\/pre>\n\n\n\n
      2.2 \u6d6e\u70b9\u7c7b\u578b\uff082 \u79cd\uff09<\/h3>\n\n\n\n
      \u7c7b\u578b<\/th>\u5360\u7528<\/th>\u7cbe\u5ea6<\/th>\u9ed8\u8ba4\u503c<\/th><\/tr><\/thead>
      float<\/code><\/td>4 \u5b57\u8282<\/td>\u7ea6 6-7 \u4f4d\u6709\u6548\u6570\u5b57<\/td>0.0f<\/td><\/tr>
      double<\/code><\/td>8 \u5b57\u8282<\/td>\u7ea6 15 \u4f4d\u6709\u6548\u6570\u5b57<\/td>0.0d<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n
      float pi = 3.1415f;      \/\/ float\uff1a\u672b\u5c3e\u5fc5\u987b\u52a0 f\ndouble salary = 12800.50; \/\/ double\uff1a\u9ed8\u8ba4\u7684\u5c0f\u6570\u7c7b\u578b\uff0c\u65e5\u5e38\u6700\u5e38\u7528<\/code><\/pre>\n\n\n\n
      \u26a0\ufe0f \u6ce8\u610f\uff1a<\/strong>\u6d6e\u70b9\u6570\u4e0d\u9002\u5408\u505a\u7cbe\u786e\u8ba1\u7b97\uff08\u6bd4\u5982\u91d1\u989d\uff09\uff0c\u56e0\u4e3a\u5b58\u5728\u7cbe\u5ea6\u4e22\u5931\u95ee\u9898\u30020.1 + 0.2 \u4e0d\u7b49\u4e8e 0.3\uff0c\u8fd9\u5728 Java \u548c\u51e0\u4e4e\u6240\u6709\u7f16\u7a0b\u8bed\u8a00\u4e2d\u90fd\u4e00\u6837\u3002\u91d1\u989d\u8ba1\u7b97\u8bf7\u7528 BigDecimal<\/code>\uff0c\u540e\u9762\u4f1a\u8bb2\u5230\u3002<\/p>\n\n\n\n
      \u9644\uff1a\u5b57\u9762\u91cf\u4e0e\u6807\u8bc6\u7b26<\/h3>\n\n\n\n
      \u5b57\u9762\u91cf\uff08Literal\uff09<\/h4>\n\n\n\n
      \u5b57\u9762\u91cf\u5c31\u662f\u76f4\u63a5\u5199\u5728\u4ee3\u7801\u4e2d\u7684”\u503c”\u3002\u4f60\u5199\u7684 int age = 25;<\/code> \u91cc\uff0c25<\/code> \u5c31\u662f\u4e00\u4e2a\u6574\u6570\u5b57\u9762\u91cf\u3002Java \u4e2d\u5e38\u89c1\u7684\u5b57\u9762\u91cf\u7c7b\u578b\uff1a<\/p>\n\n\n\n
      \u7c7b\u578b<\/th>\u793a\u4f8b<\/th>\u8bf4\u660e<\/th><\/tr><\/thead>
      \u6574\u6570\u5b57\u9762\u91cf<\/td>42<\/code>\u30010xFF<\/code>\u30010b1010<\/code>\u3001077<\/code><\/td>\u5341\u8fdb\u5236\u3001\u5341\u516d\u8fdb\u5236(0x<\/code>)\u3001\u4e8c\u8fdb\u5236(0b<\/code>)\u3001\u516b\u8fdb\u5236(0<\/code>)<\/td><\/tr>
      \u6d6e\u70b9\u5b57\u9762\u91cf<\/td>3.14<\/code>\u30011.5e10<\/code>\u30012.5f<\/code><\/td>\u9ed8\u8ba4 double<\/code>\uff0c\u52a0 f<\/code> \u4e3a float<\/code><\/td><\/tr>
      \u5b57\u7b26\u5b57\u9762\u91cf<\/td>A<\/code>\u3001\n<\/code>\u3001u0041<\/code><\/td>\u5355\u5f15\u53f7\u62ec\u8d77\u6765\uff0c\u652f\u6301\u8f6c\u4e49\u548c Unicode<\/td><\/tr>
      \u5e03\u5c14\u5b57\u9762\u91cf<\/td>true<\/code>\u3001false<\/code><\/td>\u53ea\u6709\u4fe9\u503c<\/td><\/tr>
      \u5b57\u7b26\u4e32\u5b57\u9762\u91cf<\/td>\"Hello\"<\/code>\u3001\"Java\"<\/code><\/td>\u53cc\u5f15\u53f7\u62ec\u8d77\u6765\uff0cString<\/code> \u7c7b\u578b<\/td><\/tr>
      null \u5b57\u9762\u91cf<\/td>null<\/code><\/td>\u5f15\u7528\u7c7b\u578b\u7684”\u7a7a”\u503c<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n
      Java 7+ \u7684\u6570\u503c\u5206\u9694\u7b26\uff1a<\/strong>\u53ef\u4ee5\u7528\u4e0b\u5212\u7ebf\u5206\u9694\u957f\u6570\u5b57\uff0c\u63d0\u9ad8\u53ef\u8bfb\u6027\uff0c\u7f16\u8bd1\u5668\u4f1a\u81ea\u52a8\u5ffd\u7565\u3002<\/p>\n\n\n\n
      int million = 1_000_000;        \/\/ \u4e00\u767e\u4e07\uff0c\u4e00\u773c\u5c31\u770b\u51fa\u6765\u4e86\nlong creditCard = 1234_5678_9012_3456L;\nfloat pi = 3.1415_9265F;<\/code><\/pre>\n\n\n\n
      Java 17 \u7684\u6587\u672c\u5757\uff08Text Block\uff09\uff1a<\/strong>\u591a\u884c\u5b57\u7b26\u4e32\u53ef\u4ee5\u76f4\u63a5\u7528 \"\"\" \"\"\"<\/code> \u5305\u88f9\uff0c\u4e0d\u7528\u6bcf\u884c\u672b\u5c3e\u62fc n<\/code>\u3002<\/p>\n\n\n\n
      String sql = \"\"\"\n        SELECT id, name, age\n        FROM students\n        WHERE age > 18\n        ORDER BY age DESC\n        \"\"\";<\/code><\/pre>\n\n\n\n
      \u6807\u8bc6\u7b26\uff08Identifier\uff09<\/h4>\n\n\n\n
      \u6807\u8bc6\u7b26\u5c31\u662f\u7a0b\u5e8f\u91cc\u5404\u79cd\u5143\u7d20\u7684\u540d\u5b57\u2014\u2014\u7c7b\u540d\u3001\u65b9\u6cd5\u540d\u3001\u53d8\u91cf\u540d\u3001\u63a5\u53e3\u540d\u7edf\u7edf\u7b97\u3002\u53d8\u91cf\u547d\u540d\u89c4\u5219\u4e0a\u9762\u8bf4\u8fc7\u4e86\uff0c\u8865\u5145\u4e00\u6761\u6574\u4f53\u89c4\u8303\uff1a<\/p>\n\n\n\n
        \n
      • \u7c7b\u540d\/\u63a5\u53e3\u540d<\/strong>\uff1a\u5927\u9a7c\u5cf0\uff08PascalCase\uff09\uff0c\u5982 HelloWorld<\/code>\u3001StudentManager<\/code><\/li>\n
      • \u65b9\u6cd5\u540d\/\u53d8\u91cf\u540d<\/strong>\uff1a\u5c0f\u9a7c\u5cf0\uff08camelCase\uff09\uff0c\u5982 getAge()<\/code>\u3001studentName<\/code><\/li>\n
      • \u5e38\u91cf\u540d<\/strong>\uff1a\u5168\u5927\u5199\u4e0b\u5212\u7ebf\uff0c\u5982 MAX_VALUE<\/code>\u3001DB_URL<\/code><\/li>\n
      • \u5305\u540d<\/strong>\uff1a\u5168\u5c0f\u5199\u70b9\u5206\u9694\uff0c\u5982 com.example.demo<\/code><\/li>\n<\/ul>\n\n\n\n
        \u8fd9\u90fd\u662f\u7ea6\u5b9a\u4fd7\u6210\u7684\u89c4\u8303\uff0c\u4e0d\u9075\u5b88\u7f16\u8bd1\u4e0d\u4f1a\u62a5\u9519\uff0c\u4f46\u4f1a\u88ab\u540c\u884c\u9a82\uff08\u7b11\uff09\u3002<\/p>\n\n\n\n
        2.3 \u5b57\u7b26\u7c7b\u578b\uff081 \u79cd\uff09<\/h3>\n\n\n\n
        char c1 = 'A';           \/\/ \u5355\u4e2a\u5b57\u7b26\uff0c\u7528\u5355\u5f15\u53f7\nchar c2 = '\u4e2d';          \/\/ Java \u7684 char \u662f Unicode \u7f16\u7801\uff0c\u652f\u6301\u4e2d\u6587\nchar c3 = 65;            \/\/ \u4e5f\u53ef\u4ee5\u7528 ASCII \u7801\u8d4b\u503c\uff0c65 \u5bf9\u5e94 'A'<\/code><\/pre>\n\n\n\n
        char \u5360\u7528 2 \u5b57\u8282\uff0c\u53ef\u4ee5\u5b58\u50a8\u4efb\u4f55 Unicode \u5b57\u7b26\u3002\u4f46\u6ce8\u610f\uff1a\u5b83\u662f\u57fa\u672c\u7c7b\u578b\uff0c\u4e0d\u662f\u5b57\u7b26\u4e32<\/strong>\uff0c\u53ea\u80fd\u7528\u5355\u5f15\u53f7\u62ec\u4e00\u4e2a\u5b57\u7b26\u3002<\/p>\n\n\n\n
        2.4 \u5e03\u5c14\u7c7b\u578b\uff081 \u79cd\uff09<\/h3>\n\n\n\n
        boolean isDone = true;   \/\/ \u53ea\u6709\u4e24\u4e2a\u503c\uff1atrue \/ false\nboolean isActive = false;<\/code><\/pre>\n\n\n\n
        \u5e03\u5c14\u7c7b\u578b\u5728\u6d41\u7a0b\u63a7\u5236\uff08if\u3001while\u3001for\uff09\u4e2d\u65e0\u5904\u4e0d\u5728\u3002Java \u7684 boolean \u4e0d\u80fd\u50cf C \u8bed\u8a00\u90a3\u6837\u7528 0 \u6216 1 \u66ff\u4ee3\uff0c\u5fc5\u987b\u7528 true<\/code> \/ false<\/code> \u5b57\u9762\u91cf\u3002<\/p>\n\n\n\n
        \u4e09\u3001\u7c7b\u578b\u8f6c\u6362<\/h2>\n\n\n\n
        3.1 \u81ea\u52a8\u7c7b\u578b\u8f6c\u6362\uff08\u9690\u5f0f\u8f6c\u6362\uff09<\/h3>\n\n\n\n
        \u5c0f\u8303\u56f4\u7c7b\u578b \u2192 \u5927\u8303\u56f4\u7c7b\u578b\uff0cJava \u81ea\u52a8\u5e2e\u4f60\u8f6c\uff1a<\/p>\n\n\n\n
        int num = 100;\nlong bigNum = num;      \/\/ int \u2192 long\uff0c\u81ea\u52a8\u8f6c\u6362 \u2705\ndouble d = bigNum;      \/\/ long \u2192 double\uff0c\u81ea\u52a8\u8f6c\u6362 \u2705\n\n\/\/ \u8f6c\u6362\u94fe\u6761\uff1abyte \u2192 short \u2192 int \u2192 long \u2192 float \u2192 double\n\/\/                          \u2191\n\/\/                          char \u2014\u2014 \u5411\u4e0a\u540c\u6837\u53ef\u4ee5<\/code><\/pre>\n\n\n\n
        3.2 \u5f3a\u5236\u7c7b\u578b\u8f6c\u6362\uff08\u663e\u5f0f\u8f6c\u6362\uff09<\/h3>\n\n\n\n
        \u5927\u8303\u56f4 \u2192 \u5c0f\u8303\u56f4\uff0c\u53ef\u80fd\u4e22\u5931\u7cbe\u5ea6\uff0c\u5fc5\u987b\u7a0b\u5e8f\u5458\u624b\u52a8\u5f3a\u8f6c\uff1a<\/p>\n\n\n\n
        double pi = 3.14159;\nint intPi = (int) pi;     \/\/ \u5f3a\u5236\u8f6c\u6362\uff0c\u7ed3\u679c\u4e3a 3\uff08\u5c0f\u6570\u90e8\u5206\u88ab\u622a\u65ad\uff01\uff09\n\nint big = 128;\nbyte small = (byte) big;  \/\/ \u8d85\u51fa byte \u8303\u56f4\uff08-128~127\uff09\uff0c\u6ea2\u51fa\uff01\u7ed3\u679c\u4e3a -128\n\n\/\/ \u6ea2\u51fa\u7684\u672c\u8d28\uff1a\u9ad8\u4f4d\u88ab\u622a\u65ad\u4e86\uff0c\u53ea\u4fdd\u7559\u4f4e 8 \u4f4d\n\/\/ 128 \u7684\u4e8c\u8fdb\u5236\u662f 00000000 00000000 00000000 10000000\n\/\/ \u5f3a\u8f6c\u4e3a byte \u540e\u53ea\u5269 10000000\uff08\u8865\u7801\uff09\uff0c\u5373 -128<\/code><\/pre>\n\n\n\n
        \u65b0\u624b\u6700\u5bb9\u6613\u7ffb\u7684\u8f66\uff1a<\/strong><\/p>\n\n\n\n
        \/\/ \u4e24\u4e2a int \u76f8\u9664\uff0c\u7ed3\u679c\u8fd8\u662f int\uff08\u5c0f\u6570\u88ab\u622a\u4e86\uff09\nint a = 5;\nint b = 2;\ndouble result = a \/ b;   \/\/ \u4f60\u4ee5\u4e3a\u7ed3\u679c\u662f 2.5\uff0c\u5176\u5b9e\u662f 2.0\uff01\nSystem.out.println(result); \/\/ \u8f93\u51fa 2.0\n\n\/\/ \u6b63\u786e\u505a\u6cd5\uff1a\u5148\u8f6c double\ndouble result2 = (double) a \/ b; \/\/ 2.5 \u2705\ndouble result3 = a * 1.0 \/ b;    \/\/ 2.5 \u2705<\/code><\/pre>\n\n\n\n
        \u56db\u3001\u5f15\u7528\u7c7b\u578b\u521d\u63a2<\/h2>\n\n\n\n
        \u57fa\u672c\u7c7b\u578b\u5b58\u7684\u662f”\u503c\u672c\u8eab”\uff0c\u5f15\u7528\u7c7b\u578b\u5b58\u7684\u662f”\u6307\u5411\u5bf9\u8c61\u7684\u5730\u5740”\u3002\u6700\u5e38\u89c1\u7684\u5f15\u7528\u7c7b\u578b\u5c31\u662f String<\/strong>\uff08\u5b57\u7b26\u4e32\uff09\uff1a<\/p>\n\n\n\n
        String name = \"\u4e16\u6770\";\nString greeting = \"Hello, \" + name;  \/\/ \u5b57\u7b26\u4e32\u62fc\u63a5\u7528 +\nSystem.out.println(greeting);         \/\/ Hello, \u4e16\u6770\n\n\/\/ \u533a\u522b\uff1a\u57fa\u672c\u7c7b\u578b\u7528 == \u6bd4\u8f83\u503c\uff0c\u5f15\u7528\u7c7b\u578b\u7528 .equals() \u6bd4\u8f83\u5185\u5bb9\nint a = 10;\nint b = 10;\nSystem.out.println(a == b);           \/\/ true\uff08\u6bd4\u8f83\u503c\uff09\n\nString s1 = new String(\"Java\");\nString s2 = new String(\"Java\");\nSystem.out.println(s1 == s2);         \/\/ false\uff08\u6bd4\u8f83\u7684\u662f\u5185\u5b58\u5730\u5740\uff0c\u4e0d\u662f\u5185\u5bb9\uff09\nSystem.out.println(s1.equals(s2));    \/\/ true\uff08\u6bd4\u8f83\u5185\u5bb9\uff09\n<\/code><\/pre>\n\n\n\n
        \u5173\u4e8e String \u7684\u7ec6\u8282\u975e\u5e38\u591a\uff08\u5e38\u91cf\u6c60\u3001\u4e0d\u53ef\u53d8\u6027\u3001StringBuilder \u7b49\uff09\uff0c\u540e\u9762\u4f1a\u4e13\u95e8\u5f00\u4e00\u7bc7\u8bb2\u3002\u73b0\u5728\u53ea\u9700\u8981\u8bb0\u4f4f\uff1a\u6bd4\u8f83\u5b57\u7b26\u4e32\u7528 equals\uff0c\u522b\u7528 ==<\/strong>\u3002<\/p>\n\n\n\n
        \u4e94\u3001\u5e38\u91cf\u4e0e final<\/code><\/h2>\n\n\n\n
        \u5982\u679c\u67d0\u4e2a\u503c\u5728\u7a0b\u5e8f\u8fd0\u884c\u671f\u95f4\u4e0d\u4f1a\u6539\u53d8\uff0c\u7528 final<\/code> \u5173\u952e\u5b57\u58f0\u660e\u4e3a\u5e38\u91cf\uff1a<\/p>\n\n\n\n
        final double PI = 3.14159;\nfinal int MAX_LOGIN_ATTEMPTS = 5;\n\n\/\/ PI = 3.14;  \/\/ \u274c \u7f16\u8bd1\u62a5\u9519\uff01\u5e38\u91cf\u4e0d\u80fd\u91cd\u65b0\u8d4b\u503c<\/code><\/pre>\n\n\n\n
        \u5e38\u91cf\u547d\u540d\u89c4\u8303\uff1a\u5168\u5927\u5199\u5b57\u6bcd + \u4e0b\u5212\u7ebf<\/strong>\uff0c\u4e00\u76ee\u4e86\u7136\u3002\u7528\u5e38\u91cf\u7684\u597d\u5904\u662f\uff1a<\/p>\n\n\n\n
          \n
        • \u4ee3\u7801\u53ef\u8bfb\u6027\u66f4\u597d\uff08MAX_LOGIN_ATTEMPTS<\/code> \u6bd4 5<\/code> \u542b\u4e49\u660e\u786e\u5f97\u591a\uff09<\/li>\n
        • \u4fee\u6539\u65b9\u4fbf\uff1a\u6539\u4e00\u4e2a\u5730\u65b9\uff0c\u6240\u6709\u5f15\u7528\u90fd\u66f4\u65b0<\/li>\n
        • \u9632\u6b62\u9b54\u6cd5\u6570\u5b57\uff08magic number\uff09\u6563\u843d\u5728\u4ee3\u7801\u5404\u5904<\/li>\n<\/ul>\n\n\n\n
          \n\n\n\n
          \u516d\u3001\u952e\u76d8\u5f55\u5165\uff1a\u8ba9\u7a0b\u5e8f\u8ddf\u4eba\u8bf4\u8bdd<\/h2>\n\n\n\n
          \u5230\u73b0\u5728\u6211\u4eec\u5199\u7684\u4ee3\u7801\u90fd\u662f”\u81ea\u5a31\u81ea\u4e50”\u2014\u2014\u53d8\u91cf\u503c\u5199\u5728\u4ee3\u7801\u91cc\uff0c\u5199\u597d\u5c31\u5b9a\u4e86\u3002\u600e\u4e48\u8ba9\u7a0b\u5e8f\u771f\u6b63\u8ddf\u7528\u6237\u4ea4\u4e92\uff1f\u952e\u76d8\u5f55\u5165\u8d70\u8d77\u3002<\/p>\n\n\n\n
          Java \u63d0\u4f9b\u4e86 Scanner<\/code> \u7c7b\u6765\u8bfb\u53d6\u7528\u6237\u8f93\u5165\uff0c\u5b83\u5728 java.util<\/code> \u5305\u4e0b\u9762\u3002\u4e09\u6b65\u8d70\uff1a<\/p>\n\n\n\n
            \n
          1. \u5bfc\u5305<\/strong>\uff1aimport java.util.Scanner;<\/code><\/li>\n
          2. \u521b\u5efa\u5bf9\u8c61<\/strong>\uff1aScanner sc = new Scanner(System.in);<\/code><\/li>\n
          3. \u8bfb\u53d6\u8f93\u5165<\/strong>\uff1asc.nextInt()<\/code>\u3001sc.nextDouble()<\/code>\u3001sc.nextLine()<\/code> \u7b49<\/li>\n<\/ol>\n\n\n\n
            import java.util.Scanner;\n\npublic class ScannerDemo {\n    public static void main(String[] args) {\n        Scanner sc = new Scanner(System.in);\n\n        System.out.print(\"\u8bf7\u8f93\u5165\u4f60\u7684\u540d\u5b57\uff1a\");\n        String name = sc.nextLine();\n\n        System.out.print(\"\u8bf7\u8f93\u5165\u4f60\u7684\u5e74\u9f84\uff1a\");\n        int age = sc.nextInt();\n\n        System.out.println(\"\u4f60\u597d\uff0c\" + name + \"\uff01\u4f60\u4eca\u5e74\" + age + \"\u5c81\u4e86\u3002\");\n\n        sc.close(); \/\/ \u7528\u5b8c\u5173\u6389\uff0c\u597d\u4e60\u60ef\n    }\n}<\/code><\/pre>\n\n\n\n
            \u8fd0\u884c\u540e\u63a7\u5236\u53f0\u4f1a\u7b49\u4f60\u8f93\u5165\uff0c\u8f93\u5b8c\u6309\u56de\u8f66\uff0c\u7a0b\u5e8f\u624d\u4f1a\u7ee7\u7eed\u5f80\u4e0b\u8d70\u2014\u2014\u7ec8\u4e8e\u4e0d\u518d\u662f”\u81ea\u5a31\u81ea\u4e50”\u4e86\u3002<\/p>\n\n\n\n
            \u5e38\u89c1\u7684 Scanner \u65b9\u6cd5<\/h3>\n\n\n\n
            \u65b9\u6cd5<\/th>\u8fd4\u56de\u503c<\/th>\u8bf4\u660e<\/th><\/tr><\/thead>
            nextInt()<\/code><\/td>int<\/code><\/td>\u8bfb\u53d6\u4e00\u4e2a\u6574\u6570<\/td><\/tr>
            nextDouble()<\/code><\/td>double<\/code><\/td>\u8bfb\u53d6\u4e00\u4e2a\u5c0f\u6570<\/td><\/tr>
            next()<\/code><\/td>String<\/code><\/td>\u8bfb\u53d6\u4e00\u4e2a\u5355\u8bcd\uff08\u9047\u5230\u7a7a\u683c\u505c\uff09<\/td><\/tr>
            nextLine()<\/code><\/td>String<\/code><\/td>\u8bfb\u53d6\u4e00\u6574\u884c\uff08\u5305\u62ec\u7a7a\u683c\uff09<\/td><\/tr>
            nextBoolean()<\/code><\/td>boolean<\/code><\/td>\u8bfb\u53d6 true<\/code> \u6216 false<\/code><\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n
            \u26a0\ufe0f \u5c0f\u9677\u9631\uff1a<\/strong>nextInt()<\/code> \u540e\u63a5 nextLine()<\/code> \u4f1a\u51fa\u73b0”\u541e\u56de\u8f66”\u95ee\u9898\u3002\u56e0\u4e3a nextInt()<\/code> \u53ea\u8bfb\u53d6\u6570\u5b57\u4e0d\u8bfb\u53d6\u540e\u9762\u7684\u6362\u884c\u7b26\uff0c\u7d27\u63a5\u7740 nextLine()<\/code> \u5c31\u8bfb\u5230\u4e86\u8fd9\u4e2a\u7a7a\u884c\u3002\u89e3\u51b3\u65b9\u6848\u662f\u5728\u4e24\u8005\u4e4b\u95f4\u52a0\u4e00\u4e2a sc.nextLine()<\/code> \u628a\u6362\u884c\u7b26\u5403\u6389\u3002<\/p>\n\n\n\n
            System.out.print(\"\u8bf7\u8f93\u5165\u5e74\u9f84\uff1a\");\nint age = sc.nextInt();\nsc.nextLine(); \/\/ \ud83d\udc48 \u5403\u6389\u6362\u884c\u7b26\n\nSystem.out.print(\"\u8bf7\u8f93\u5165\u59d3\u540d\uff1a\");\nString name = sc.nextLine(); \/\/ \u8fd9\u56de\u6b63\u5e38\u4e86<\/code><\/pre>\n\n\n\n
            \u8fd9\u4e2a\u5751\u5b66 Java \u7684\u4eba\u51e0\u4e4e\u90fd\u8e29\u8fc7\uff0c\u4f60\u4e5f\u8fdf\u65e9\u4f1a\u8e29\u5230\uff0c\u63d0\u524d\u77e5\u9053\u4e0d\u5403\u4e8f\u3002<\/p>\n\n\n\n
            \u7ed3\u8bed<\/h2>\n\n\n\n
            \u4eca\u5929\u6211\u4eec\u628a Java \u7684 8 \u79cd\u57fa\u672c\u6570\u636e\u7c7b\u578b\u6328\u4e2a\u634b\u4e86\u4e00\u904d\uff0c\u641e\u6e05\u4e86\u53d8\u91cf\u7684\u58f0\u660e\u3001\u8d4b\u503c\u3001\u547d\u540d\u89c4\u8303\uff0c\u8fd8\u77e5\u9053\u4e86\u7c7b\u578b\u8f6c\u6362\u4ec0\u4e48\u65f6\u5019\u4f1a\u81ea\u52a8\u53d1\u751f\u3001\u4ec0\u4e48\u65f6\u5019\u4f1a\u6ea2\u51fa\u3002\u6700\u540e\u7528\u4e00\u4e2a String \u793a\u4f8b\u5f15\u5165\u4e86\u5f15\u7528\u7c7b\u578b\u7684\u6982\u5ff5\uff0c\u4e5f\u63d0\u9192\u4e86\u4f60\u90a3\u4e2a equals<\/code> \u548c ==<\/code> \u7684\u9009\u62e9\u9898\u2014\u2014\u9762\u8bd5\u91cc\u8fd9\u4e2a\u5751\u51e0\u4e4e\u5fc5\u8003\u3002<\/p>\n\n\n\n
            \u4e0b\u4e00\u7bc7\u6211\u4eec\u7ee7\u7eed\u6df1\u5165\u57fa\u7840\u8bed\u6cd5\uff0c\u770b\u770b\u8fd0\u7b97\u7b26\u3001\u8868\u8fbe\u5f0f\u548c\u6d41\u7a0b\u63a7\u5236\u2014\u2014if\u3001for\u3001while \u8fd9\u4e9b\u4f60\u5199\u6bcf\u884c\u4ee3\u7801\u90fd\u79bb\u4e0d\u5f00\u7684\u4e1c\u897f\uff0c\u5230\u5e95\u6709\u54ea\u4e9b\u503c\u5f97\u6ce8\u610f\u7684\u7ec6\u8282\u3002<\/p>\n\n","protected":false},"excerpt":{"rendered":"
            \u4ece HelloWorld \u5230\u771f\u6b63\u5199\u51fa\u6709\u7528\u7684\u7a0b\u5e8f\uff0c\u4f60\u9047\u5230\u7684\u7b2c\u4e00\u4e2a\u5c94\u8def\u53e3\u5c31\u662f\uff1a\u6570\u636e\u600e\u4e48\u5b58\uff0c\u53d8\u91cf\u600e\u4e48\u7528\u3002\u7c7b\u578b\u58f0\u660e\u3001\u8d4b […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[34,10],"tags":[61,64,62,63],"class_list":["post-211","post","type-post","status-publish","format-standard","hentry","category-01-","category-javase","tag-java","tag-64","tag-62","tag-63"],"_links":{"self":[{"href":"https:\/\/ssjava.xyz\/index.php\/wp-json\/wp\/v2\/posts\/211","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/ssjava.xyz\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/ssjava.xyz\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/ssjava.xyz\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/ssjava.xyz\/index.php\/wp-json\/wp\/v2\/comments?post=211"}],"version-history":[{"count":2,"href":"https:\/\/ssjava.xyz\/index.php\/wp-json\/wp\/v2\/posts\/211\/revisions"}],"predecessor-version":[{"id":216,"href":"https:\/\/ssjava.xyz\/index.php\/wp-json\/wp\/v2\/posts\/211\/revisions\/216"}],"wp:attachment":[{"href":"https:\/\/ssjava.xyz\/index.php\/wp-json\/wp\/v2\/media?parent=211"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/ssjava.xyz\/index.php\/wp-json\/wp\/v2\/categories?post=211"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/ssjava.xyz\/index.php\/wp-json\/wp\/v2\/tags?post=211"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}