{"id":1340,"date":"2022-10-30T22:48:51","date_gmt":"2022-10-30T14:48:51","guid":{"rendered":"https:\/\/qaqaq.top\/?p=1340"},"modified":"2022-11-27T12:39:46","modified_gmt":"2022-11-27T04:39:46","slug":"io%e6%b5%81%e4%b8%8e%e7%bd%91%e7%bb%9c%e7%bc%96%e7%a8%8b-randomaccessfile%e5%ae%9e%e7%8e%b0%e6%95%b0%e6%8d%ae%e7%9a%84%e8%af%bb%e5%86%99%e6%93%8d%e4%bd%9c%e3%80%81randomaccessfile%e5%ae%9e%e7%8e%b0","status":"publish","type":"post","link":"https:\/\/qaqaq.top\/?p=1340","title":{"rendered":"IO\u6d41\u4e0e\u7f51\u7edc\u7f16\u7a0b-RandomAccessFile\u5b9e\u73b0\u6570\u636e\u7684\u8bfb\u5199\u64cd\u4f5c\u3001RandomAccessFile\u5b9e\u73b0\u6570\u636e\u7684\u63d2\u5165"},"content":{"rendered":"\n<pre class=\"wp-block-code\"><code>package top.qaqaq.java.P616;\r\n\r\nimport org.junit.jupiter.api.Test;\r\n\r\nimport java.io.File;\r\nimport java.io.IOException;\r\nimport java.io.RandomAccessFile;\r\n\r\n\/**\r\n * RandomAccessFile\u7684\u4f7f\u7528\r\n * 1. RandomAccessFile\u76f4\u63a5\u7ee7\u627f\u4e8ejava.lang.Object\u7c7b\uff0c\u5b9e\u73b0\u4e86DataInput\u548cDataOutput\u63a5\u53e3\r\n * 2. RandomAccessFile\u65e2\u53ef\u4ee5\u4f5c\u4e3a\u4e00\u4e2a\u8f93\u5165\u6d41\uff0c\u53c8\u53ef\u4ee5\u4f5c\u4e3a\u4e00\u4e2a\u8f93\u51fa\u6d41\r\n\r\n * 3. \u5982\u679cRandomAccessFile\u4f5c\u4e3a\u8f93\u51fa\u6d41\u65f6\uff0c\u5199\u51fa\u5230\u7684\u6587\u4ef6\u5982\u679c\u4e0d\u5b58\u5728\uff0c\u5219\u5728\u6267\u884c\u8fc7\u7a0b\u4e2d\u81ea\u52a8\u521b\u5efa\r\n *    \u5982\u679c\u5199\u51fa\u5230\u7684\u6587\u4ef6\u5b58\u5728\uff0c\u5219\u4f1a\u5bf9\u539f\u6709\u6587\u4ef6\u5185\u5bb9\u8fdb\u884c\u8986\u76d6\u3002\uff08\u9ed8\u8ba4\u60c5\u51b5\u4e0b\uff0c\u4ece\u5934\u8986\u76d6\uff09\r\n *\r\n * 4. \u53ef\u4ee5\u901a\u8fc7\u76f8\u5173\u7684\u64cd\u4f5c\uff0c\u5b9e\u73b0RandomAccessFile\"\u63d2\u5165\"\u6570\u636e\u7684\u6548\u679c\r\n *\r\n * @author RichieZhang\r\n * @create 2022-10-30 \u4e0b\u5348 8:24\r\n *\/\r\npublic class RandomAccessFileTest {\r\n\r\n    @Test\r\n    public void test1() {\r\n\r\n        RandomAccessFile raf1 = null;\r\n        RandomAccessFile raf2 = null;\r\n        try {\r\n            \/\/1.\r\n            raf1 = new RandomAccessFile(new File(\"\u7231\u60c5\u4e0e\u53cb\u60c5.jpg\"),\"r\");\r\n            raf2 = new RandomAccessFile(new File(\"\u7231\u60c5\u4e0e\u53cb\u60c56.jpg\"),\"rw\");\r\n            \/\/2.\r\n            byte&#91;] buffer = new byte&#91;1024];\r\n            int len;\r\n            while ((len = raf1.read(buffer)) != -1){\r\n                raf2.write(buffer,0,len);\r\n            }\r\n        } catch (IOException e) {\r\n            e.printStackTrace();\r\n        } finally {\r\n            \/\/3.\r\n            if (raf1 != null){\r\n                try {\r\n                    raf1.close();\r\n                } catch (IOException e) {\r\n                    e.printStackTrace();\r\n                }\r\n            }\r\n            if (raf2 != null){\r\n                try {\r\n                    raf2.close();\r\n                } catch (IOException e) {\r\n                    e.printStackTrace();\r\n                }\r\n            }\r\n        }\r\n\r\n    }\r\n\r\n    @Test\r\n    public void test2() throws IOException {\r\n        RandomAccessFile raf1 = new RandomAccessFile(\"hello.txt\", \"rw\");\r\n\r\n        raf1.seek(3);\/\/\u5c06\u6307\u9488\u8c03\u5230\u89d2\u6807\u4e3a3\u7684\u4f4d\u7f6e\r\n        raf1.write(\"xyz\".getBytes());\/\/\u8986\u76d6\u6570\u636e\r\n\r\n        raf1.close();\r\n    }\r\n\r\n    \/*\r\n    \u4f7f\u7528RandomAccessFile\u5b9e\u73b0\u6570\u636e\u7684\u63d2\u5165\u6548\u679c\r\n     *\/\r\n    @Test\r\n    public void test3() throws IOException {\r\n        RandomAccessFile raf1 = new RandomAccessFile(\"hello.txt\", \"rw\");\r\n\r\n        raf1.seek(3);\/\/\u5c06\u6307\u9488\u8c03\u5230\u89d2\u6807\u4e3a3\u7684\u4f4d\u7f6e\r\n        \/\/\u4fdd\u5b58\u6307\u94883\u540e\u9762\u7684\u6240\u6709\u6570\u636e\u5230StringBuilder\u4e2d\r\n        StringBuilder builder = new StringBuilder((int) new File(\"hello.txt\").length());\r\n        byte&#91;] buffer = new byte&#91;20];\r\n        int len;\r\n        while ((len = raf1.read(buffer)) != -1){\r\n            builder.append(new String(buffer,0,len));\r\n\r\n        }\r\n        \/\/\u8c03\u56de\u6307\u9488\uff0c\u5199\u5165\"xyz\"\r\n        raf1.seek(3);\r\n        raf1.write(\"xyz\".getBytes());\r\n\r\n        \/\/\u5c06StringBuilder\u4e2d\u7684\u6570\u636e\u5199\u5165\u5230\u6587\u4ef6\u4e2d\r\n        raf1.write(builder.toString().getBytes());\r\n    }\r\n\r\n    \/\/\u601d\u8003\uff1a\u5c06StringBuilder\u66ff\u6362\u4e3aByteArrayOutputStream\r\n}\r\n<\/code><\/pre>\n","protected":false},"excerpt":{"rendered":"","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[8],"tags":[46],"class_list":["post-1340","post","type-post","status-publish","format-standard","hentry","category-java-code","tag-java"],"_links":{"self":[{"href":"https:\/\/qaqaq.top\/index.php?rest_route=\/wp\/v2\/posts\/1340"}],"collection":[{"href":"https:\/\/qaqaq.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/qaqaq.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/qaqaq.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/qaqaq.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=1340"}],"version-history":[{"count":1,"href":"https:\/\/qaqaq.top\/index.php?rest_route=\/wp\/v2\/posts\/1340\/revisions"}],"predecessor-version":[{"id":1341,"href":"https:\/\/qaqaq.top\/index.php?rest_route=\/wp\/v2\/posts\/1340\/revisions\/1341"}],"wp:attachment":[{"href":"https:\/\/qaqaq.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1340"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/qaqaq.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=1340"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/qaqaq.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=1340"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}