{"id":19414,"date":"2024-03-15T18:49:51","date_gmt":"2024-03-15T18:49:51","guid":{"rendered":"https:\/\/www.silicloud.com\/blog\/how-to-implement-telnet-in-java-to-access-switch-ports\/"},"modified":"2024-03-21T15:38:44","modified_gmt":"2024-03-21T15:38:44","slug":"how-to-implement-telnet-in-java-to-access-switch-ports","status":"publish","type":"post","link":"https:\/\/www.silicloud.com\/blog\/how-to-implement-telnet-in-java-to-access-switch-ports\/","title":{"rendered":"How to implement telnet in Java to access switch ports?"},"content":{"rendered":"<p>In order to obtain port information from a switch using Java, you can establish a Telnet connection by using Java&#8217;s Socket and TelnetClient classes. Below is a simple example code.<\/p>\n<pre class=\"post-pre\"><code><span class=\"hljs-keyword\">import<\/span> org.apache.commons.net.telnet.*;\r\n\r\n<span class=\"hljs-keyword\">public<\/span> <span class=\"hljs-keyword\">class<\/span> <span class=\"hljs-title class_\">TelnetExample<\/span> {\r\n    <span class=\"hljs-keyword\">public<\/span> <span class=\"hljs-keyword\">static<\/span> <span class=\"hljs-keyword\">void<\/span> <span class=\"hljs-title function_\">main<\/span><span class=\"hljs-params\">(String[] args)<\/span> {\r\n        <span class=\"hljs-type\">String<\/span> <span class=\"hljs-variable\">host<\/span> <span class=\"hljs-operator\">=<\/span> <span class=\"hljs-string\">\"\u4ea4\u6362\u673aIP\"<\/span>;\r\n        <span class=\"hljs-type\">int<\/span> <span class=\"hljs-variable\">port<\/span> <span class=\"hljs-operator\">=<\/span> <span class=\"hljs-number\">23<\/span>;\r\n        <span class=\"hljs-type\">String<\/span> <span class=\"hljs-variable\">user<\/span> <span class=\"hljs-operator\">=<\/span> <span class=\"hljs-string\">\"\u7528\u6237\u540d\"<\/span>;\r\n        <span class=\"hljs-type\">String<\/span> <span class=\"hljs-variable\">password<\/span> <span class=\"hljs-operator\">=<\/span> <span class=\"hljs-string\">\"\u5bc6\u7801\"<\/span>;\r\n\r\n        <span class=\"hljs-keyword\">try<\/span> {\r\n            <span class=\"hljs-type\">TelnetClient<\/span> <span class=\"hljs-variable\">client<\/span> <span class=\"hljs-operator\">=<\/span> <span class=\"hljs-keyword\">new<\/span> <span class=\"hljs-title class_\">TelnetClient<\/span>();\r\n            client.connect(host, port);\r\n\r\n            <span class=\"hljs-comment\">\/\/ \u83b7\u53d6\u8f93\u5165\u6d41\u548c\u8f93\u51fa\u6d41<\/span>\r\n            <span class=\"hljs-type\">InputStream<\/span> <span class=\"hljs-variable\">in<\/span> <span class=\"hljs-operator\">=<\/span> client.getInputStream();\r\n            <span class=\"hljs-type\">PrintStream<\/span> <span class=\"hljs-variable\">out<\/span> <span class=\"hljs-operator\">=<\/span> <span class=\"hljs-keyword\">new<\/span> <span class=\"hljs-title class_\">PrintStream<\/span>(client.getOutputStream());\r\n\r\n            <span class=\"hljs-comment\">\/\/ \u767b\u5f55<\/span>\r\n            readUntil(in, <span class=\"hljs-string\">\"Username:\"<\/span>);\r\n            write(out, user);\r\n            readUntil(in, <span class=\"hljs-string\">\"Password:\"<\/span>);\r\n            write(out, password);\r\n\r\n            <span class=\"hljs-comment\">\/\/ \u6267\u884c\u547d\u4ee4<\/span>\r\n            write(out, <span class=\"hljs-string\">\"show interfaces brief\"<\/span>);\r\n\r\n            <span class=\"hljs-comment\">\/\/ \u8bfb\u53d6\u547d\u4ee4\u8f93\u51fa\u7ed3\u679c<\/span>\r\n            <span class=\"hljs-type\">String<\/span> <span class=\"hljs-variable\">result<\/span> <span class=\"hljs-operator\">=<\/span> readUntil(in, <span class=\"hljs-string\">\"\u4ea4\u6362\u673a\u63d0\u793a\u7b26\"<\/span>);\r\n\r\n            <span class=\"hljs-comment\">\/\/ \u5904\u7406\u547d\u4ee4\u8f93\u51fa\u7ed3\u679c<\/span>\r\n            <span class=\"hljs-comment\">\/\/ ...<\/span>\r\n\r\n            <span class=\"hljs-comment\">\/\/ \u5173\u95ed\u8fde\u63a5<\/span>\r\n            client.disconnect();\r\n        } <span class=\"hljs-keyword\">catch<\/span> (Exception e) {\r\n            e.printStackTrace();\r\n        }\r\n    }\r\n\r\n    <span class=\"hljs-keyword\">private<\/span> <span class=\"hljs-keyword\">static<\/span> <span class=\"hljs-keyword\">void<\/span> <span class=\"hljs-title function_\">write<\/span><span class=\"hljs-params\">(PrintStream out, String value)<\/span> {\r\n        out.println(value);\r\n        out.flush();\r\n    }\r\n\r\n    <span class=\"hljs-keyword\">private<\/span> <span class=\"hljs-keyword\">static<\/span> String <span class=\"hljs-title function_\">readUntil<\/span><span class=\"hljs-params\">(InputStream in, String pattern)<\/span> <span class=\"hljs-keyword\">throws<\/span> IOException {\r\n        <span class=\"hljs-type\">StringBuilder<\/span> <span class=\"hljs-variable\">sb<\/span> <span class=\"hljs-operator\">=<\/span> <span class=\"hljs-keyword\">new<\/span> <span class=\"hljs-title class_\">StringBuilder<\/span>();\r\n        <span class=\"hljs-type\">char<\/span> <span class=\"hljs-variable\">lastChar<\/span> <span class=\"hljs-operator\">=<\/span> pattern.charAt(pattern.length() - <span class=\"hljs-number\">1<\/span>);\r\n        <span class=\"hljs-type\">char<\/span>[] chars = <span class=\"hljs-keyword\">new<\/span> <span class=\"hljs-title class_\">char<\/span>[<span class=\"hljs-number\">1024<\/span>];\r\n        <span class=\"hljs-type\">int<\/span> read;\r\n        <span class=\"hljs-keyword\">while<\/span> ((read = in.read(chars)) != -<span class=\"hljs-number\">1<\/span>) {\r\n            sb.append(chars, <span class=\"hljs-number\">0<\/span>, read);\r\n            <span class=\"hljs-keyword\">if<\/span> (sb.charAt(sb.length() - <span class=\"hljs-number\">1<\/span>) == lastChar) {\r\n                <span class=\"hljs-keyword\">if<\/span> (sb.toString().endsWith(pattern)) {\r\n                    <span class=\"hljs-keyword\">return<\/span> sb.toString();\r\n                }\r\n            }\r\n        }\r\n        <span class=\"hljs-keyword\">return<\/span> sb.toString();\r\n    }\r\n}\r\n<\/code><\/pre>\n<p>Please be sure to replace the following variables in the code:<\/p>\n<ol>\n<li>host: IP address of the switch<\/li>\n<li>Port: Default port for Telnet is 23.<\/li>\n<li>User: Telnet login username<\/li>\n<li>Password: Telnet login password<\/li>\n<li>Command to execute in order to obtain port information: &#8220;show interfaces brief&#8221;<\/li>\n<li>&#8220;Switch Prompt&#8221;: The prompt of a switch, used in the command output to determine when the command has been executed.<\/li>\n<\/ol>\n<p>You need to replace the placeholders in the code above with actual values, and handle them accordingly based on the command output format of the Telnet switch you are using.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>In order to obtain port information from a switch using Java, you can establish a Telnet connection by using Java&#8217;s Socket and TelnetClient classes. Below is a simple example code. import org.apache.commons.net.telnet.*; public class TelnetExample { public static void main(String[] args) { String host = &#8220;\u4ea4\u6362\u673aIP&#8221;; int port = 23; String user = &#8220;\u7528\u6237\u540d&#8221;; String [&hellip;]<\/p>\n","protected":false},"author":6,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_import_markdown_pro_load_document_selector":0,"_import_markdown_pro_submit_text_textarea":"","footnotes":""},"categories":[1],"tags":[],"class_list":["post-19414","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"yoast_head":"<!-- This site is optimized with the Yoast SEO Premium plugin v21.5 (Yoast SEO v21.5) - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>How to implement telnet in Java to access switch ports? - Blog - Silicon Cloud<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/www.silicloud.com\/blog\/how-to-implement-telnet-in-java-to-access-switch-ports\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"How to implement telnet in Java to access switch ports?\" \/>\n<meta property=\"og:description\" content=\"In order to obtain port information from a switch using Java, you can establish a Telnet connection by using Java&#8217;s Socket and TelnetClient classes. Below is a simple example code. import org.apache.commons.net.telnet.*; public class TelnetExample { public static void main(String[] args) { String host = &quot;\u4ea4\u6362\u673aIP&quot;; int port = 23; String user = &quot;\u7528\u6237\u540d&quot;; String [&hellip;]\" \/>\n<meta property=\"og:url\" content=\"https:\/\/www.silicloud.com\/blog\/how-to-implement-telnet-in-java-to-access-switch-ports\/\" \/>\n<meta property=\"og:site_name\" content=\"Blog - Silicon Cloud\" \/>\n<meta property=\"article:publisher\" content=\"https:\/\/www.facebook.com\/SiliCloudGlobal\/\" \/>\n<meta property=\"article:published_time\" content=\"2024-03-15T18:49:51+00:00\" \/>\n<meta property=\"article:modified_time\" content=\"2024-03-21T15:38:44+00:00\" \/>\n<meta name=\"author\" content=\"Benjamin Taylor\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:creator\" content=\"@SiliCloudGlobal\" \/>\n<meta name=\"twitter:site\" content=\"@SiliCloudGlobal\" \/>\n<meta name=\"twitter:label1\" content=\"Written by\" \/>\n\t<meta name=\"twitter:data1\" content=\"Benjamin Taylor\" \/>\n\t<meta name=\"twitter:label2\" content=\"Est. reading time\" \/>\n\t<meta name=\"twitter:data2\" content=\"1 minute\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\/\/schema.org\",\"@graph\":[{\"@type\":\"Article\",\"@id\":\"https:\/\/www.silicloud.com\/blog\/how-to-implement-telnet-in-java-to-access-switch-ports\/#article\",\"isPartOf\":{\"@id\":\"https:\/\/www.silicloud.com\/blog\/how-to-implement-telnet-in-java-to-access-switch-ports\/\"},\"author\":{\"name\":\"Benjamin Taylor\",\"@id\":\"https:\/\/www.silicloud.com\/blog\/#\/schema\/person\/ac801fe9549a25960ce48aa2e0a691c9\"},\"headline\":\"How to implement telnet in Java to access switch ports?\",\"datePublished\":\"2024-03-15T18:49:51+00:00\",\"dateModified\":\"2024-03-21T15:38:44+00:00\",\"mainEntityOfPage\":{\"@id\":\"https:\/\/www.silicloud.com\/blog\/how-to-implement-telnet-in-java-to-access-switch-ports\/\"},\"wordCount\":134,\"commentCount\":0,\"publisher\":{\"@id\":\"https:\/\/www.silicloud.com\/blog\/#organization\"},\"inLanguage\":\"en-US\"},{\"@type\":\"WebPage\",\"@id\":\"https:\/\/www.silicloud.com\/blog\/how-to-implement-telnet-in-java-to-access-switch-ports\/\",\"url\":\"https:\/\/www.silicloud.com\/blog\/how-to-implement-telnet-in-java-to-access-switch-ports\/\",\"name\":\"How to implement telnet in Java to access switch ports? 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