{"id":4078,"date":"2018-08-24T20:40:04","date_gmt":"2018-08-24T12:40:04","guid":{"rendered":"https:\/\/ixyzero.com\/blog\/?p=4078"},"modified":"2018-08-24T20:40:04","modified_gmt":"2018-08-24T12:40:04","slug":"java%e4%b8%ad%e7%9a%84%e4%b8%80%e4%ba%9b%e5%9f%ba%e7%a1%80%e4%bb%a3%e7%a0%81%e7%89%87%e6%ae%b5_5","status":"publish","type":"post","link":"https:\/\/ixyzero.com\/blog\/archives\/4078.html","title":{"rendered":"Java\u4e2d\u7684\u4e00\u4e9b\u57fa\u7840\u4ee3\u7801\u7247\u6bb5_5"},"content":{"rendered":"<p>=Start=<\/p>\n<h4 id=\"id-\u6a21\u677f-\u7f18\u7531\uff1a\">\u7f18\u7531\uff1a<\/h4>\n<p>\u5728\u7528Java\u7f16\u7a0b\u7684\u8fc7\u7a0b\u4e2d\u4e0d\u65ad\u7528\u6587\u7ae0\u8fdb\u884c\u6574\u7406\u603b\u7ed3\uff08\u5e38\u7528\u529f\u80fd\u7684Java\u5b9e\u73b0\uff09\uff0c\u4e89\u53d6\u65e9\u65e5\u80fd\u975e\u5e38\u719f\u7ec3\u7684\u4f7f\u7528Java\u8fdb\u884c\u5f00\u53d1\u3002<\/p>\n<h4 id=\"id-\u6a21\u677f-\u6b63\u6587\uff1a\">\u6b63\u6587\uff1a<\/h4>\n<h5 id=\"id-\u6a21\u677f-\u53c2\u8003\u89e3\u7b54\uff1a\">\u53c2\u8003\u89e3\u7b54\uff1a<\/h5>\n<h6>0.Java\u4e2d\u5b57\u7b26\u4e32\u5207\u5206\u5e76\u586b\u5145JSONObject\u65f6\u7684\u95ee\u9898<\/h6>\n<ul>\n<li><a href=\"https:\/\/blog.csdn.net\/u010900574\/article\/details\/50790800\">Java JSONObject\u6570\u7ec4\u4f7f\u7528\u65f6\u51fa\u73b0&#8221;nullpointerexception&#8221;\u7684\u89e3\u51b3\u529e\u6cd5<\/a><\/li>\n<\/ul>\n<pre class=\"lang:default decode:true \">package com.ixyzero.learn.utils;\r\n\r\nimport com.alibaba.fastjson.JSONObject;\r\n\r\npublic class DoSplitTest {\r\n    public static void main(String[] args) {\r\n        String raw = \"2018-07-15 11:26:32.040 hostname  #TAGS#{ ip=}#TAGS# #MESSAGE#{\\\"data\\\":\\\"some data\\\",\\\"type\\\":\\\"app_1\\\",\\\"os\\\":\\\"Android\\\",\\\"version\\\":\\\"1.3.7\\\",\\\"time\\\":\\\"2018-07-15 11:26:31\\\"}#MESSAGE#\";\r\n        String ip = raw.substring(raw.indexOf(\"#TAGS#{\")+11, raw.indexOf(\"}#TAGS#\"));\r\n        System.out.println(\"ip = '\" + ip + \"'\");\r\n\r\n        raw = \"2018-07-14 11:27:25.103 hostname  #TAGS#{ uuid=22046941-958B-4D5C-6T83-XY3PO9UI ip=}#TAGS# #MESSAGE#{\\\"data\\\": \\\"some data\\\",\\\"type\\\": \\\"app_2\\\",\\\"os\\\": \\\"iOS\\\",\\\"dateTime\\\": \\\"2018-06-04 15:31:40\\\",\\\"version\\\": \\\"1.0.6\\\"}#MESSAGE#\";\r\n        ip = raw.substring(raw.indexOf(\"#TAGS#{\")+8, raw.indexOf(\"}#TAGS#\"));\r\n        System.out.println(\"ip = '\" + ip + \"'\");\r\n\r\n        String tags = raw.substring(raw.indexOf(\"#TAGS#{\")+8, raw.indexOf(\"}#TAGS#\"));\r\n        System.out.println(\"'\" + tags + \"'\");\r\n\r\n        JSONObject jsonObject = new JSONObject();\r\n        for (String item: tags.split(\" \")) {\r\n            \/\/ System.out.println(item);\r\n            String[] arr = item.split(\"=\", 2);\r\n            \/\/ for (int i=0; i&lt;arr.length; i++) {\r\n            \/\/     System.out.println(i + \":\\t'\" + arr[i] + \"'\");\r\n            \/\/ }\r\n            \/\/ System.out.println(arr.length);\r\n            \/\/ System.out.print(arr[0] + \"\\t'\");\r\n            \/\/ System.out.println(arr[1] + \"'\");\r\n            \/\/ String value = arr[1].isEmpty() ? \"xnull\" : arr[1];\r\n            \/\/ System.out.println(value);\r\n            \/\/ jsonObject.put(arr[0], value);\r\n\r\n            jsonObject.put(arr[0], arr[1]);\r\n\r\n            \/\/ if (arr.length == 2) {\r\n            \/\/     try {\r\n            \/\/         jsonObject.put(arr[0], arr[1]);\r\n            \/\/     } catch (Exception e) {\r\n            \/\/         jsonObject.put(arr[0], \"\");\r\n            \/\/     }\r\n            \/\/ }\r\n        }\r\n        System.out.println(jsonObject);\r\n    }\r\n}\r\n<\/pre>\n<p>&nbsp;<\/p>\n<h6>1.\u5728Java\u4e2d\u4f7f\u7528CRC32\u8fdb\u884c\u6821\u9a8c<\/h6>\n<ul>\n<li><a href=\"https:\/\/blog.csdn.net\/tbkken\/article\/details\/8210952\">\u5728Java\u4e2d\u4f7f\u7528CRC32<\/a><\/li>\n<li><a href=\"https:\/\/blog.csdn.net\/jianggujin\/article\/details\/53444286\">JAVA\u5faa\u73af\u5197\u4f59\u6821\u9a8c\uff08CRC32\uff09<\/a><br \/>\n<a href=\"https:\/\/docs.oracle.com\/javase\/7\/docs\/api\/java\/util\/zip\/CRC32.html\">https:\/\/docs.oracle.com\/javase\/7\/docs\/api\/java\/util\/zip\/CRC32.html<\/a><\/li>\n<li><a href=\"https:\/\/www.w3cschool.cn\/java\/java-io-zip-byte-array.html\">Java Zip\u5b57\u8282\u6570\u7ec4<\/a><\/li>\n<\/ul>\n<pre class=\"lang:default decode:true\">package com.ixyzero.learn.utils;\r\n\r\nimport com.google.common.primitives.Longs;\r\n\r\nimport java.util.Arrays;\r\nimport java.util.zip.CRC32;\r\n\r\npublic class DoCRC32 {\r\n    private static CRC32 crc32;\r\n    private static byte[] initBytes = new byte[] {0, 0, 0, 0, 0, 0, 0, 0, 0, 0};\r\n\r\n    public static void main(String[] args) {\r\n        String inputStr = \"hello-world\";\r\n        System.out.println(\"raw: \" + inputStr);\r\n        byte[] inputByte = inputStr.getBytes();\r\n        System.out.println(\"byte array: \" + Arrays.toString(inputByte));\r\n\r\n        crc32 = new CRC32();\r\n        crc32.update(inputByte);\r\n        long crc32Result = crc32.getValue();\r\n        System.out.println(\"crc32: \" + crc32Result);\r\n\r\n        byte[] bytes = Longs.toByteArray(crc32Result);\r\n        System.out.println(\"crc32 size: \" + bytes.length);\r\n        System.out.println(\"byte array: \" + Arrays.toString(bytes));\r\n\r\n        System.out.println(\"initBytes: \" + Arrays.toString(initBytes));\r\n    }\r\n}<\/pre>\n<h6>2.\u5728Java\u4e2d\u5982\u4f55\u5c06 long \u8f6c\u6362\u6210 byte[]<\/h6>\n<ul>\n<li><a href=\"https:\/\/stackoverflow.com\/questions\/4485128\/how-do-i-convert-long-to-byte-and-back-in-java\">How do I convert Long to byte[] and back in java<\/a><\/li>\n<li><a href=\"https:\/\/stackoverflow.com\/questions\/4299111\/convert-long-to-byte-array-and-add-it-to-another-array\">Convert long to byte array and add it to another array<\/a><\/li>\n<\/ul>\n<pre class=\"lang:default decode:true\">import com.google.common.primitives.Longs;\r\n\r\nbyte[] bytes = Longs.toByteArray(12345L);<\/pre>\n<h6>3.\u5728Java\u4e2d\u5982\u4f55\u5feb\u901f\u5bf9 byte[] \u6570\u7ec4\u521d\u59cb\u5316<\/h6>\n<ul>\n<li><a href=\"https:\/\/www.tutorialspoint.com\/java\/util\/arrays_fill_byte.htm\">Java\u4e2d\u5982\u4f55\u5bf9 byte[] \u6570\u7ec4\u521d\u59cb\u5316\u586b\u51650<\/a><\/li>\n<li><a href=\"https:\/\/stackoverflow.com\/questions\/11208479\/how-do-i-initialize-a-byte-array-in-java\">How do I initialize a byte array in Java?<\/a><\/li>\n<\/ul>\n<pre class=\"lang:default decode:true\">byte arr[] = new byte[] {0, 0, 0};\r\n\/\/ \u4e0b\u9762\u8fd9\u6837\u4e5f\u884c\r\nArrays.fill(arr, (byte)0);<\/pre>\n<h6>4.\u5728Java\u4e2d\u5982\u4f55\u622a\u53d6\/\u83b7\u53d6 byte[] \u6570\u7ec4\u7684\u4e00\u90e8\u5206<\/h6>\n<ul>\n<li><a href=\"https:\/\/stackoverflow.com\/questions\/18367539\/slicing-byte-arrays-in-java\">Java\u4e2d\u5982\u4f55\u622a\u53d6\/\u83b7\u53d6 byte[] \u7684\u4e00\u90e8\u5206<\/a><\/li>\n<\/ul>\n<pre class=\"lang:default decode:true\">\/\/ slice from index 5 to index 9\r\nbyte[] slice = Arrays.copyOfRange(myArray, 5, 10);\r\n<\/pre>\n<h6>5.Java\u4e2d byte[] \u6570\u7ec4\u7684\u62f7\u8d1d\u548c\u590d\u5236<\/h6>\n<ul>\n<li><a href=\"https:\/\/blog.csdn.net\/kesalin\/article\/details\/566354\">\u4f7f\u7528System.arraycopy()\u5b9e\u73b0\u6570\u7ec4\u4e4b\u95f4\u7684\u590d\u5236<\/a><\/li>\n<li><a href=\"https:\/\/blog.csdn.net\/oChangWen\/article\/details\/50587937\">Java\u65b9\u6cd5\u4e4b&#8211;System.arraycopy\u65b9\u6cd5\u548cArrays.copyOf()<\/a><\/li>\n<li><a href=\"https:\/\/www.cnblogs.com\/yakovchang\/p\/java_system_arraycopy.html\">Java\u6027\u80fd\u6f2b\u8c08\uff0d\u6570\u7ec4\u590d\u5236\u4e4bSystem.arraycopy<\/a><\/li>\n<li><a href=\"https:\/\/www.jianshu.com\/p\/840976f14950\">Java\u4e2dSystem.arraycopy()\u548cArrays.copyOf()\u7684\u533a\u522b<\/a><\/li>\n<\/ul>\n<pre class=\"lang:default decode:true\">\/\/ Java \u4e2d System.arraycopy \u65b9\u6cd5\u7684\u53c2\u6570\u5217\u8868\r\nSystem.arraycopy(Object src,\r\n\t\t\t\tint srcPos,\r\n\t\t\t \tObject dest,\r\n\t\t\t \tint destPos,\r\n\t\t\t \tint length\r\n)\r\n\r\n\/*\r\nJava\u4e2dSystem.arraycopy()\u548cArrays.copyOf()\u4e24\u8005\u7684\u533a\u522b\u5728\u4e8e\uff1a\r\narraycopy()\u9700\u8981\u76ee\u6807\u6570\u7ec4\uff0c\u5c06\u539f\u6570\u7ec4\u62f7\u8d1d\u5230\u4f60\u81ea\u5df1\u5b9a\u4e49\u7684\u6570\u7ec4\u91cc\uff0c\u800c\u4e14\u53ef\u4ee5\u9009\u62e9\u62f7\u8d1d\u7684\u8d77\u70b9\u548c\u957f\u5ea6\u4ee5\u53ca\u653e\u5165\u65b0\u6570\u7ec4\u4e2d\u7684\u4f4d\u7f6e\uff1b\r\ncopyOf()\u662f\u7cfb\u7edf\u81ea\u52a8\u5728\u5185\u90e8\u65b0\u5efa\u4e00\u4e2a\u6570\u7ec4\uff0c\u8c03\u7528arraycopy()\u5c06original\u5185\u5bb9\u590d\u5236\u5230copy\u4e2d\u53bb\uff0c\u5e76\u4e14\u957f\u5ea6\u4e3anewLength\u3002\u8fd4\u56decopy; \u5373\u5c06\u539f\u6570\u7ec4\u62f7\u8d1d\u5230\u4e00\u4e2a\u957f\u5ea6\u4e3anewLength\u7684\u65b0\u6570\u7ec4\u4e2d\uff0c\u5e76\u8fd4\u56de\u8be5\u6570\u7ec4\u3002\r\n\r\n\u603b\u7ed3\uff1a\r\nArray.copyOf()\u53ef\u4ee5\u770b\u4f5c\u662f\u53d7\u9650\u7684System.arraycopy()\uff0c\u5b83\u4e3b\u8981\u662f\u7528\u6765\u5c06\u539f\u6570\u7ec4\u5168\u90e8\u62f7\u8d1d\u5230\u4e00\u4e2a\u65b0\u957f\u5ea6\u7684\u6570\u7ec4\uff0c\u9002\u7528\u4e8e\u6570\u7ec4\u6269\u5bb9\u3002\r\n*\/<\/pre>\n<h6>6.Java\u4e2d\u5982\u4f55\u8f83\u4e3a\u53cb\u597d\u7684\u6253\u5370 byte[] \u6570\u7ec4<\/h6>\n<ul>\n<li><a href=\"https:\/\/stackoverflow.com\/questions\/6463580\/how-to-print-the-data-in-byte-array-as-characters\/6463665#6463665\">Java\u4e2d\u5982\u4f55\u6253\u5370 byte[]<\/a><\/li>\n<li><a href=\"https:\/\/stackoverflow.com\/questions\/409784\/whats-the-simplest-way-to-print-a-java-array\">Java\u4e2d\u6253\u5370\u6570\u7ec4\u7684\u6700\u7b80\u5355\u65b9\u6cd5<\/a><\/li>\n<\/ul>\n<pre class=\"lang:default decode:true\"># \u7b80\u5355\u6570\u7ec4(\u5404\u79cd\u7c7b\u578b\u90fd\u53ef\u4ee5\uff0c\u6bd4\u5982 int\/double\/String\/byte)\r\nString[] array = new String[] {\"John\", \"Mary\", \"Bob\"};\r\nSystem.out.println(Arrays.toString(array));\r\n\r\n# \u5d4c\u5957\u6570\u7ec4\r\nString[][] deepArray = new String[][] {{\"John\", \"Mary\"}, {\"Alice\", \"Bob\"}};\r\nSystem.out.println(Arrays.toString(deepArray));\r\n\/\/ output: [[Ljava.lang.String;@106d69c, [Ljava.lang.String;@52e922]\r\nSystem.out.println(Arrays.deepToString(deepArray));\r\n\/\/ [[John, Mary], [Alice, Bob]]<\/pre>\n<p>&nbsp;<\/p>\n<h5 id=\"id-\u6a21\u677f-\u53c2\u8003\u94fe\u63a5\uff1a\">\u53c2\u8003\u94fe\u63a5\uff1a<\/h5>\n<ul>\n<li>\u5982\u4e0a<\/li>\n<\/ul>\n<p>=END=<\/p>\n","protected":false},"excerpt":{"rendered":"<p>=Start= \u7f18\u7531\uff1a \u5728\u7528Java\u7f16\u7a0b\u7684\u8fc7\u7a0b\u4e2d\u4e0d\u65ad\u7528\u6587\u7ae0\u8fdb\u884c\u6574\u7406\u603b\u7ed3\uff08\u5e38\u7528\u529f\u80fd\u7684Java\u5b9e\u73b0\uff09\uff0c\u4e89\u53d6\u65e9\u65e5\u80fd\u975e [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[23,7],"tags":[930,61,19],"class_list":["post-4078","post","type-post","status-publish","format-standard","hentry","category-knowledgebase-2","category-programing","tag-code","tag-java","tag-tips"],"views":5977,"_links":{"self":[{"href":"https:\/\/ixyzero.com\/blog\/wp-json\/wp\/v2\/posts\/4078","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/ixyzero.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/ixyzero.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/ixyzero.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/ixyzero.com\/blog\/wp-json\/wp\/v2\/comments?post=4078"}],"version-history":[{"count":1,"href":"https:\/\/ixyzero.com\/blog\/wp-json\/wp\/v2\/posts\/4078\/revisions"}],"predecessor-version":[{"id":4079,"href":"https:\/\/ixyzero.com\/blog\/wp-json\/wp\/v2\/posts\/4078\/revisions\/4079"}],"wp:attachment":[{"href":"https:\/\/ixyzero.com\/blog\/wp-json\/wp\/v2\/media?parent=4078"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/ixyzero.com\/blog\/wp-json\/wp\/v2\/categories?post=4078"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/ixyzero.com\/blog\/wp-json\/wp\/v2\/tags?post=4078"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}