{"id":293,"date":"2026-02-14T14:12:53","date_gmt":"2026-02-14T13:12:53","guid":{"rendered":"http:\/\/www.ccorreas.es\/wordpress\/?p=293"},"modified":"2026-02-14T14:12:53","modified_gmt":"2026-02-14T13:12:53","slug":"recorrer-map-en-java","status":"publish","type":"post","link":"https:\/\/www.ccorreas.es\/wordpress\/index.php\/2026\/02\/14\/recorrer-map-en-java\/","title":{"rendered":"Recorrer Map en Java"},"content":{"rendered":"\n<p class=\"wp-block-paragraph\">Creamos el Map.<\/p>\n\n\n\n<div class=\"wp-block-kevinbatdorf-code-block-pro\" data-code-block-pro-font-family=\"Code-Pro-JetBrains-Mono\" style=\"font-size:clamp(14px, .875rem, 21px);font-family:Code-Pro-JetBrains-Mono,ui-monospace,SFMono-Regular,Menlo,Monaco,Consolas,monospace;line-height:clamp(20px, 1.25rem, 30px);--cbp-tab-width:2;tab-size:var(--cbp-tab-width, 2)\"><span style=\"display:block;padding:16px 0 0 16px;margin-bottom:-1px;width:100%;text-align:left;background-color:#2e3440ff\"><svg xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"54\" height=\"14\" viewBox=\"0 0 54 14\"><g fill=\"none\" fill-rule=\"evenodd\" transform=\"translate(1 1)\"><circle cx=\"6\" cy=\"6\" r=\"6\" fill=\"#FF5F56\" stroke=\"#E0443E\" stroke-width=\".5\"><\/circle><circle cx=\"26\" cy=\"6\" r=\"6\" fill=\"#FFBD2E\" stroke=\"#DEA123\" stroke-width=\".5\"><\/circle><circle cx=\"46\" cy=\"6\" r=\"6\" fill=\"#27C93F\" stroke=\"#1AAB29\" stroke-width=\".5\"><\/circle><\/g><\/svg><\/span><span role=\"button\" tabindex=\"0\" style=\"color:#d8dee9ff;display:none\" aria-label=\"Copy\" class=\"code-block-pro-copy-button\"><pre class=\"code-block-pro-copy-button-pre\" aria-hidden=\"true\"><textarea class=\"code-block-pro-copy-button-textarea\" tabindex=\"-1\" aria-hidden=\"true\" readonly>     Map&lt;Libro, ArrayList&lt;Integer>> mapaLibros = new HashMap&lt;>();\n\n        mapaLibros.put(new Libro(\"maria\", \"pepa\", 15.20), new ArrayList&lt;>());\n        mapaLibros.put(new Libro(\"jose\", \"pepe\", 12.20), new ArrayList&lt;>());\n        mapaLibros.put(new Libro(\"cristian\", \"carlos\", 15.20), new ArrayList&lt;>());\n<\/textarea><\/pre><svg xmlns=\"http:\/\/www.w3.org\/2000\/svg\" style=\"width:24px;height:24px\" fill=\"none\" viewBox=\"0 0 24 24\" stroke=\"currentColor\" stroke-width=\"2\"><path class=\"with-check\" stroke-linecap=\"round\" stroke-linejoin=\"round\" d=\"M9 5H7a2 2 0 00-2 2v12a2 2 0 002 2h10a2 2 0 002-2V7a2 2 0 00-2-2h-2M9 5a2 2 0 002 2h2a2 2 0 002-2M9 5a2 2 0 012-2h2a2 2 0 012 2m-6 9l2 2 4-4\"><\/path><path class=\"without-check\" stroke-linecap=\"round\" stroke-linejoin=\"round\" d=\"M9 5H7a2 2 0 00-2 2v12a2 2 0 002 2h10a2 2 0 002-2V7a2 2 0 00-2-2h-2M9 5a2 2 0 002 2h2a2 2 0 002-2M9 5a2 2 0 012-2h2a2 2 0 012 2\"><\/path><\/svg><\/span><pre class=\"shiki nord\" style=\"background-color: #2e3440ff\" tabindex=\"0\"><code><span class=\"line\"><span style=\"color: #D8DEE9FF\">     <\/span><span style=\"color: #8FBCBB\">Map<\/span><span style=\"color: #ECEFF4\">&lt;<\/span><span style=\"color: #8FBCBB\">Libro<\/span><span style=\"color: #ECEFF4\">,<\/span><span style=\"color: #D8DEE9FF\"> <\/span><span style=\"color: #8FBCBB\">ArrayList<\/span><span style=\"color: #ECEFF4\">&lt;<\/span><span style=\"color: #8FBCBB\">Integer<\/span><span style=\"color: #ECEFF4\">&gt;&gt;<\/span><span style=\"color: #D8DEE9FF\"> <\/span><span style=\"color: #D8DEE9\">mapaLibros<\/span><span style=\"color: #D8DEE9FF\"> <\/span><span style=\"color: #81A1C1\">=<\/span><span style=\"color: #D8DEE9FF\"> <\/span><span style=\"color: #81A1C1\">new<\/span><span style=\"color: #D8DEE9FF\"> <\/span><span style=\"color: #8FBCBB\">HashMap<\/span><span style=\"color: #ECEFF4\">&lt;&gt;()<\/span><span style=\"color: #81A1C1\">;<\/span><\/span>\n<span class=\"line\"><\/span>\n<span class=\"line\"><span style=\"color: #D8DEE9FF\">        <\/span><span style=\"color: #D8DEE9\">mapaLibros<\/span><span style=\"color: #ECEFF4\">.<\/span><span style=\"color: #88C0D0\">put<\/span><span style=\"color: #ECEFF4\">(<\/span><span style=\"color: #81A1C1\">new<\/span><span style=\"color: #D8DEE9FF\"> <\/span><span style=\"color: #88C0D0\">Libro<\/span><span style=\"color: #ECEFF4\">(<\/span><span style=\"color: #ECEFF4\">&quot;<\/span><span style=\"color: #A3BE8C\">maria<\/span><span style=\"color: #ECEFF4\">&quot;<\/span><span style=\"color: #ECEFF4\">,<\/span><span style=\"color: #D8DEE9FF\"> <\/span><span style=\"color: #ECEFF4\">&quot;<\/span><span style=\"color: #A3BE8C\">pepa<\/span><span style=\"color: #ECEFF4\">&quot;<\/span><span style=\"color: #ECEFF4\">,<\/span><span style=\"color: #D8DEE9FF\"> <\/span><span style=\"color: #B48EAD\">15.20<\/span><span style=\"color: #ECEFF4\">),<\/span><span style=\"color: #D8DEE9FF\"> <\/span><span style=\"color: #81A1C1\">new<\/span><span style=\"color: #D8DEE9FF\"> <\/span><span style=\"color: #8FBCBB\">ArrayList<\/span><span style=\"color: #ECEFF4\">&lt;&gt;())<\/span><span style=\"color: #81A1C1\">;<\/span><\/span>\n<span class=\"line\"><span style=\"color: #D8DEE9FF\">        <\/span><span style=\"color: #D8DEE9\">mapaLibros<\/span><span style=\"color: #ECEFF4\">.<\/span><span style=\"color: #88C0D0\">put<\/span><span style=\"color: #ECEFF4\">(<\/span><span style=\"color: #81A1C1\">new<\/span><span style=\"color: #D8DEE9FF\"> <\/span><span style=\"color: #88C0D0\">Libro<\/span><span style=\"color: #ECEFF4\">(<\/span><span style=\"color: #ECEFF4\">&quot;<\/span><span style=\"color: #A3BE8C\">jose<\/span><span style=\"color: #ECEFF4\">&quot;<\/span><span style=\"color: #ECEFF4\">,<\/span><span style=\"color: #D8DEE9FF\"> <\/span><span style=\"color: #ECEFF4\">&quot;<\/span><span style=\"color: #A3BE8C\">pepe<\/span><span style=\"color: #ECEFF4\">&quot;<\/span><span style=\"color: #ECEFF4\">,<\/span><span style=\"color: #D8DEE9FF\"> <\/span><span style=\"color: #B48EAD\">12.20<\/span><span style=\"color: #ECEFF4\">),<\/span><span style=\"color: #D8DEE9FF\"> <\/span><span style=\"color: #81A1C1\">new<\/span><span style=\"color: #D8DEE9FF\"> <\/span><span style=\"color: #8FBCBB\">ArrayList<\/span><span style=\"color: #ECEFF4\">&lt;&gt;())<\/span><span style=\"color: #81A1C1\">;<\/span><\/span>\n<span class=\"line\"><span style=\"color: #D8DEE9FF\">        <\/span><span style=\"color: #D8DEE9\">mapaLibros<\/span><span style=\"color: #ECEFF4\">.<\/span><span style=\"color: #88C0D0\">put<\/span><span style=\"color: #ECEFF4\">(<\/span><span style=\"color: #81A1C1\">new<\/span><span style=\"color: #D8DEE9FF\"> <\/span><span style=\"color: #88C0D0\">Libro<\/span><span style=\"color: #ECEFF4\">(<\/span><span style=\"color: #ECEFF4\">&quot;<\/span><span style=\"color: #A3BE8C\">cristian<\/span><span style=\"color: #ECEFF4\">&quot;<\/span><span style=\"color: #ECEFF4\">,<\/span><span style=\"color: #D8DEE9FF\"> <\/span><span style=\"color: #ECEFF4\">&quot;<\/span><span style=\"color: #A3BE8C\">carlos<\/span><span style=\"color: #ECEFF4\">&quot;<\/span><span style=\"color: #ECEFF4\">,<\/span><span style=\"color: #D8DEE9FF\"> <\/span><span style=\"color: #B48EAD\">15.20<\/span><span style=\"color: #ECEFF4\">),<\/span><span style=\"color: #D8DEE9FF\"> <\/span><span style=\"color: #81A1C1\">new<\/span><span style=\"color: #D8DEE9FF\"> <\/span><span style=\"color: #8FBCBB\">ArrayList<\/span><span style=\"color: #ECEFF4\">&lt;&gt;())<\/span><span style=\"color: #81A1C1\">;<\/span><\/span>\n<span class=\"line\"><\/span><\/code><\/pre><\/div>\n\n\n\n<p class=\"wp-block-paragraph\">Recorrer el Map creando un Set.<\/p>\n\n\n\n<div class=\"wp-block-kevinbatdorf-code-block-pro\" data-code-block-pro-font-family=\"Code-Pro-JetBrains-Mono\" style=\"font-size:clamp(14px, .875rem, 21px);font-family:Code-Pro-JetBrains-Mono,ui-monospace,SFMono-Regular,Menlo,Monaco,Consolas,monospace;line-height:clamp(20px, 1.25rem, 30px);--cbp-tab-width:2;tab-size:var(--cbp-tab-width, 2)\"><span style=\"display:block;padding:16px 0 0 16px;margin-bottom:-1px;width:100%;text-align:left;background-color:#2e3440ff\"><svg xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"54\" height=\"14\" viewBox=\"0 0 54 14\"><g fill=\"none\" fill-rule=\"evenodd\" transform=\"translate(1 1)\"><circle cx=\"6\" cy=\"6\" r=\"6\" fill=\"#FF5F56\" stroke=\"#E0443E\" stroke-width=\".5\"><\/circle><circle cx=\"26\" cy=\"6\" r=\"6\" fill=\"#FFBD2E\" stroke=\"#DEA123\" stroke-width=\".5\"><\/circle><circle cx=\"46\" cy=\"6\" r=\"6\" fill=\"#27C93F\" stroke=\"#1AAB29\" stroke-width=\".5\"><\/circle><\/g><\/svg><\/span><span role=\"button\" tabindex=\"0\" style=\"color:#d8dee9ff;display:none\" aria-label=\"Copy\" class=\"code-block-pro-copy-button\"><pre class=\"code-block-pro-copy-button-pre\" aria-hidden=\"true\"><textarea class=\"code-block-pro-copy-button-textarea\" tabindex=\"-1\" aria-hidden=\"true\" readonly> Set&lt;Map.Entry&lt;Libro, ArrayList&lt;Integer>>> entradas = mapaLibros.entrySet();\n        for ( Map.Entry&lt;Libro, ArrayList&lt;Integer>> e:entradas){\n            ArrayList&lt;Integer> notas = e.getValue();\n            for (int i = 0; i &lt; 3; i++) {\n                notas.add(getNumeroAleatorio(1,10));\n            }\n        }\n\n        for ( Map.Entry&lt;Libro, ArrayList&lt;Integer>> e:entradas){\n            System.out.println(e.getKey());\n            ArrayList&lt;Integer> notas = e.getValue();\n            System.out.println(notas);\n        }<\/textarea><\/pre><svg xmlns=\"http:\/\/www.w3.org\/2000\/svg\" style=\"width:24px;height:24px\" fill=\"none\" viewBox=\"0 0 24 24\" stroke=\"currentColor\" stroke-width=\"2\"><path class=\"with-check\" stroke-linecap=\"round\" stroke-linejoin=\"round\" d=\"M9 5H7a2 2 0 00-2 2v12a2 2 0 002 2h10a2 2 0 002-2V7a2 2 0 00-2-2h-2M9 5a2 2 0 002 2h2a2 2 0 002-2M9 5a2 2 0 012-2h2a2 2 0 012 2m-6 9l2 2 4-4\"><\/path><path class=\"without-check\" stroke-linecap=\"round\" stroke-linejoin=\"round\" d=\"M9 5H7a2 2 0 00-2 2v12a2 2 0 002 2h10a2 2 0 002-2V7a2 2 0 00-2-2h-2M9 5a2 2 0 002 2h2a2 2 0 002-2M9 5a2 2 0 012-2h2a2 2 0 012 2\"><\/path><\/svg><\/span><pre class=\"shiki nord\" style=\"background-color: #2e3440ff\" tabindex=\"0\"><code><span class=\"line\"><span style=\"color: #D8DEE9FF\"> <\/span><span style=\"color: #8FBCBB\">Set<\/span><span style=\"color: #ECEFF4\">&lt;<\/span><span style=\"color: #8FBCBB\">Map<\/span><span style=\"color: #ECEFF4\">.<\/span><span style=\"color: #8FBCBB\">Entry<\/span><span style=\"color: #ECEFF4\">&lt;<\/span><span style=\"color: #8FBCBB\">Libro<\/span><span style=\"color: #ECEFF4\">,<\/span><span style=\"color: #D8DEE9FF\"> <\/span><span style=\"color: #8FBCBB\">ArrayList<\/span><span style=\"color: #ECEFF4\">&lt;<\/span><span style=\"color: #8FBCBB\">Integer<\/span><span style=\"color: #ECEFF4\">&gt;&gt;&gt;<\/span><span style=\"color: #D8DEE9FF\"> <\/span><span style=\"color: #D8DEE9\">entradas<\/span><span style=\"color: #D8DEE9FF\"> <\/span><span style=\"color: #81A1C1\">=<\/span><span style=\"color: #D8DEE9FF\"> <\/span><span style=\"color: #D8DEE9\">mapaLibros<\/span><span style=\"color: #ECEFF4\">.<\/span><span style=\"color: #88C0D0\">entrySet<\/span><span style=\"color: #ECEFF4\">()<\/span><span style=\"color: #81A1C1\">;<\/span><\/span>\n<span class=\"line\"><span style=\"color: #D8DEE9FF\">        <\/span><span style=\"color: #81A1C1\">for<\/span><span style=\"color: #D8DEE9FF\"> <\/span><span style=\"color: #ECEFF4\">(<\/span><span style=\"color: #D8DEE9FF\"> <\/span><span style=\"color: #8FBCBB\">Map<\/span><span style=\"color: #ECEFF4\">.<\/span><span style=\"color: #8FBCBB\">Entry<\/span><span style=\"color: #ECEFF4\">&lt;<\/span><span style=\"color: #8FBCBB\">Libro<\/span><span style=\"color: #ECEFF4\">,<\/span><span style=\"color: #D8DEE9FF\"> <\/span><span style=\"color: #8FBCBB\">ArrayList<\/span><span style=\"color: #ECEFF4\">&lt;<\/span><span style=\"color: #8FBCBB\">Integer<\/span><span style=\"color: #ECEFF4\">&gt;&gt;<\/span><span style=\"color: #D8DEE9FF\"> <\/span><span style=\"color: #D8DEE9\">e<\/span><span style=\"color: #81A1C1\">:<\/span><span style=\"color: #D8DEE9FF\">entradas<\/span><span style=\"color: #ECEFF4\">){<\/span><\/span>\n<span class=\"line\"><span style=\"color: #D8DEE9FF\">            <\/span><span style=\"color: #8FBCBB\">ArrayList<\/span><span style=\"color: #ECEFF4\">&lt;<\/span><span style=\"color: #8FBCBB\">Integer<\/span><span style=\"color: #ECEFF4\">&gt;<\/span><span style=\"color: #D8DEE9FF\"> <\/span><span style=\"color: #D8DEE9\">notas<\/span><span style=\"color: #D8DEE9FF\"> <\/span><span style=\"color: #81A1C1\">=<\/span><span style=\"color: #D8DEE9FF\"> <\/span><span style=\"color: #D8DEE9\">e<\/span><span style=\"color: #ECEFF4\">.<\/span><span style=\"color: #88C0D0\">getValue<\/span><span style=\"color: #ECEFF4\">()<\/span><span style=\"color: #81A1C1\">;<\/span><\/span>\n<span class=\"line\"><span style=\"color: #D8DEE9FF\">            <\/span><span style=\"color: #81A1C1\">for<\/span><span style=\"color: #D8DEE9FF\"> <\/span><span style=\"color: #ECEFF4\">(<\/span><span style=\"color: #81A1C1\">int<\/span><span style=\"color: #D8DEE9FF\"> <\/span><span style=\"color: #D8DEE9\">i<\/span><span style=\"color: #D8DEE9FF\"> <\/span><span style=\"color: #81A1C1\">=<\/span><span style=\"color: #D8DEE9FF\"> <\/span><span style=\"color: #B48EAD\">0<\/span><span style=\"color: #81A1C1\">;<\/span><span style=\"color: #D8DEE9FF\"> i <\/span><span style=\"color: #81A1C1\">&lt;<\/span><span style=\"color: #D8DEE9FF\"> <\/span><span style=\"color: #B48EAD\">3<\/span><span style=\"color: #81A1C1\">;<\/span><span style=\"color: #D8DEE9FF\"> i<\/span><span style=\"color: #81A1C1\">++<\/span><span style=\"color: #ECEFF4\">)<\/span><span style=\"color: #D8DEE9FF\"> <\/span><span style=\"color: #ECEFF4\">{<\/span><\/span>\n<span class=\"line\"><span style=\"color: #D8DEE9FF\">                <\/span><span style=\"color: #D8DEE9\">notas<\/span><span style=\"color: #ECEFF4\">.<\/span><span style=\"color: #88C0D0\">add<\/span><span style=\"color: #ECEFF4\">(<\/span><span style=\"color: #88C0D0\">getNumeroAleatorio<\/span><span style=\"color: #ECEFF4\">(<\/span><span style=\"color: #B48EAD\">1<\/span><span style=\"color: #ECEFF4\">,<\/span><span style=\"color: #B48EAD\">10<\/span><span style=\"color: #ECEFF4\">))<\/span><span style=\"color: #81A1C1\">;<\/span><\/span>\n<span class=\"line\"><span style=\"color: #D8DEE9FF\">            <\/span><span style=\"color: #ECEFF4\">}<\/span><\/span>\n<span class=\"line\"><span style=\"color: #D8DEE9FF\">        <\/span><span style=\"color: #ECEFF4\">}<\/span><\/span>\n<span class=\"line\"><\/span>\n<span class=\"line\"><span style=\"color: #D8DEE9FF\">        <\/span><span style=\"color: #81A1C1\">for<\/span><span style=\"color: #D8DEE9FF\"> <\/span><span style=\"color: #ECEFF4\">(<\/span><span style=\"color: #D8DEE9FF\"> <\/span><span style=\"color: #8FBCBB\">Map<\/span><span style=\"color: #ECEFF4\">.<\/span><span style=\"color: #8FBCBB\">Entry<\/span><span style=\"color: #ECEFF4\">&lt;<\/span><span style=\"color: #8FBCBB\">Libro<\/span><span style=\"color: #ECEFF4\">,<\/span><span style=\"color: #D8DEE9FF\"> <\/span><span style=\"color: #8FBCBB\">ArrayList<\/span><span style=\"color: #ECEFF4\">&lt;<\/span><span style=\"color: #8FBCBB\">Integer<\/span><span style=\"color: #ECEFF4\">&gt;&gt;<\/span><span style=\"color: #D8DEE9FF\"> <\/span><span style=\"color: #D8DEE9\">e<\/span><span style=\"color: #81A1C1\">:<\/span><span style=\"color: #D8DEE9FF\">entradas<\/span><span style=\"color: #ECEFF4\">){<\/span><\/span>\n<span class=\"line\"><span style=\"color: #D8DEE9FF\">            <\/span><span style=\"color: #D8DEE9\">System<\/span><span style=\"color: #ECEFF4\">.<\/span><span style=\"color: #D8DEE9\">out<\/span><span style=\"color: #ECEFF4\">.<\/span><span style=\"color: #88C0D0\">println<\/span><span style=\"color: #ECEFF4\">(<\/span><span style=\"color: #D8DEE9\">e<\/span><span style=\"color: #ECEFF4\">.<\/span><span style=\"color: #88C0D0\">getKey<\/span><span style=\"color: #ECEFF4\">())<\/span><span style=\"color: #81A1C1\">;<\/span><\/span>\n<span class=\"line\"><span style=\"color: #D8DEE9FF\">            <\/span><span style=\"color: #8FBCBB\">ArrayList<\/span><span style=\"color: #ECEFF4\">&lt;<\/span><span style=\"color: #8FBCBB\">Integer<\/span><span style=\"color: #ECEFF4\">&gt;<\/span><span style=\"color: #D8DEE9FF\"> <\/span><span style=\"color: #D8DEE9\">notas<\/span><span style=\"color: #D8DEE9FF\"> <\/span><span style=\"color: #81A1C1\">=<\/span><span style=\"color: #D8DEE9FF\"> <\/span><span style=\"color: #D8DEE9\">e<\/span><span style=\"color: #ECEFF4\">.<\/span><span style=\"color: #88C0D0\">getValue<\/span><span style=\"color: #ECEFF4\">()<\/span><span style=\"color: #81A1C1\">;<\/span><\/span>\n<span class=\"line\"><span style=\"color: #D8DEE9FF\">            <\/span><span style=\"color: #D8DEE9\">System<\/span><span style=\"color: #ECEFF4\">.<\/span><span style=\"color: #D8DEE9\">out<\/span><span style=\"color: #ECEFF4\">.<\/span><span style=\"color: #88C0D0\">println<\/span><span style=\"color: #ECEFF4\">(<\/span><span style=\"color: #D8DEE9FF\">notas<\/span><span style=\"color: #ECEFF4\">)<\/span><span style=\"color: #81A1C1\">;<\/span><\/span>\n<span class=\"line\"><span style=\"color: #D8DEE9FF\">        <\/span><span style=\"color: #ECEFF4\">}<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n<p class=\"wp-block-paragraph\">Serializar\/Deserializar<\/p>\n\n\n\n<div class=\"wp-block-kevinbatdorf-code-block-pro\" data-code-block-pro-font-family=\"Code-Pro-JetBrains-Mono\" style=\"font-size:clamp(14px, .875rem, 21px);font-family:Code-Pro-JetBrains-Mono,ui-monospace,SFMono-Regular,Menlo,Monaco,Consolas,monospace;line-height:clamp(20px, 1.25rem, 30px);--cbp-tab-width:2;tab-size:var(--cbp-tab-width, 2)\"><span style=\"display:block;padding:16px 0 0 16px;margin-bottom:-1px;width:100%;text-align:left;background-color:#2e3440ff\"><svg xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"54\" height=\"14\" viewBox=\"0 0 54 14\"><g fill=\"none\" fill-rule=\"evenodd\" transform=\"translate(1 1)\"><circle cx=\"6\" cy=\"6\" r=\"6\" fill=\"#FF5F56\" stroke=\"#E0443E\" stroke-width=\".5\"><\/circle><circle cx=\"26\" cy=\"6\" r=\"6\" fill=\"#FFBD2E\" stroke=\"#DEA123\" stroke-width=\".5\"><\/circle><circle cx=\"46\" cy=\"6\" r=\"6\" fill=\"#27C93F\" stroke=\"#1AAB29\" stroke-width=\".5\"><\/circle><\/g><\/svg><\/span><span role=\"button\" tabindex=\"0\" style=\"color:#d8dee9ff;display:none\" aria-label=\"Copy\" class=\"code-block-pro-copy-button\"><pre class=\"code-block-pro-copy-button-pre\" aria-hidden=\"true\"><textarea class=\"code-block-pro-copy-button-textarea\" tabindex=\"-1\" aria-hidden=\"true\" readonly>  \/\/SERIALIZAR\n        Gson json = new GsonBuilder().enableComplexMapKeySerialization().setPrettyPrinting().create();\n        String mapaString = json.toJson(mapaLibros);\n        System.out.println(mapaString);\n\n        \/\/DESERIALIZAR\n        Type tipo = new TypeToken&lt;Map&lt;Libro, ArrayList&lt;Integer>>>(){}.getType();\n        Map&lt;Libro, ArrayList&lt;Integer>> mapaRecuperado = json.fromJson(mapaString, tipo);\n\n        for ( Map.Entry&lt;Libro, ArrayList&lt;Integer>> e:mapaRecuperado.entrySet()){\n            System.out.println(e.getKey());\n            ArrayList&lt;Integer> notas = e.getValue();\n            System.out.println(notas);\n        }<\/textarea><\/pre><svg xmlns=\"http:\/\/www.w3.org\/2000\/svg\" style=\"width:24px;height:24px\" fill=\"none\" viewBox=\"0 0 24 24\" stroke=\"currentColor\" stroke-width=\"2\"><path class=\"with-check\" stroke-linecap=\"round\" stroke-linejoin=\"round\" d=\"M9 5H7a2 2 0 00-2 2v12a2 2 0 002 2h10a2 2 0 002-2V7a2 2 0 00-2-2h-2M9 5a2 2 0 002 2h2a2 2 0 002-2M9 5a2 2 0 012-2h2a2 2 0 012 2m-6 9l2 2 4-4\"><\/path><path class=\"without-check\" stroke-linecap=\"round\" stroke-linejoin=\"round\" d=\"M9 5H7a2 2 0 00-2 2v12a2 2 0 002 2h10a2 2 0 002-2V7a2 2 0 00-2-2h-2M9 5a2 2 0 002 2h2a2 2 0 002-2M9 5a2 2 0 012-2h2a2 2 0 012 2\"><\/path><\/svg><\/span><pre class=\"shiki nord\" style=\"background-color: #2e3440ff\" tabindex=\"0\"><code><span class=\"line\"><span style=\"color: #ECEFF4\">  <\/span><span style=\"color: #616E88\">\/\/SERIALIZAR<\/span><\/span>\n<span class=\"line\"><span style=\"color: #D8DEE9FF\">        <\/span><span style=\"color: #8FBCBB\">Gson<\/span><span style=\"color: #D8DEE9FF\"> <\/span><span style=\"color: #D8DEE9\">json<\/span><span style=\"color: #D8DEE9FF\"> <\/span><span style=\"color: #81A1C1\">=<\/span><span style=\"color: #D8DEE9FF\"> <\/span><span style=\"color: #81A1C1\">new<\/span><span style=\"color: #D8DEE9FF\"> <\/span><span style=\"color: #88C0D0\">GsonBuilder<\/span><span style=\"color: #ECEFF4\">().<\/span><span style=\"color: #88C0D0\">enableComplexMapKeySerialization<\/span><span style=\"color: #ECEFF4\">().<\/span><span style=\"color: #88C0D0\">setPrettyPrinting<\/span><span style=\"color: #ECEFF4\">().<\/span><span style=\"color: #88C0D0\">create<\/span><span style=\"color: #ECEFF4\">()<\/span><span style=\"color: #81A1C1\">;<\/span><\/span>\n<span class=\"line\"><span style=\"color: #D8DEE9FF\">        <\/span><span style=\"color: #8FBCBB\">String<\/span><span style=\"color: #D8DEE9FF\"> <\/span><span style=\"color: #D8DEE9\">mapaString<\/span><span style=\"color: #D8DEE9FF\"> <\/span><span style=\"color: #81A1C1\">=<\/span><span style=\"color: #D8DEE9FF\"> <\/span><span style=\"color: #D8DEE9\">json<\/span><span style=\"color: #ECEFF4\">.<\/span><span style=\"color: #88C0D0\">toJson<\/span><span style=\"color: #ECEFF4\">(<\/span><span style=\"color: #D8DEE9FF\">mapaLibros<\/span><span style=\"color: #ECEFF4\">)<\/span><span style=\"color: #81A1C1\">;<\/span><\/span>\n<span class=\"line\"><span style=\"color: #D8DEE9FF\">        <\/span><span style=\"color: #D8DEE9\">System<\/span><span style=\"color: #ECEFF4\">.<\/span><span style=\"color: #D8DEE9\">out<\/span><span style=\"color: #ECEFF4\">.<\/span><span style=\"color: #88C0D0\">println<\/span><span style=\"color: #ECEFF4\">(<\/span><span style=\"color: #D8DEE9FF\">mapaString<\/span><span style=\"color: #ECEFF4\">)<\/span><span style=\"color: #81A1C1\">;<\/span><\/span>\n<span class=\"line\"><\/span>\n<span class=\"line\"><span style=\"color: #ECEFF4\">        <\/span><span style=\"color: #616E88\">\/\/DESERIALIZAR<\/span><\/span>\n<span class=\"line\"><span style=\"color: #D8DEE9FF\">        <\/span><span style=\"color: #8FBCBB\">Type<\/span><span style=\"color: #D8DEE9FF\"> <\/span><span style=\"color: #D8DEE9\">tipo<\/span><span style=\"color: #D8DEE9FF\"> <\/span><span style=\"color: #81A1C1\">=<\/span><span style=\"color: #D8DEE9FF\"> <\/span><span style=\"color: #81A1C1\">new<\/span><span style=\"color: #D8DEE9FF\"> <\/span><span style=\"color: #8FBCBB\">TypeToken<\/span><span style=\"color: #ECEFF4\">&lt;<\/span><span style=\"color: #8FBCBB\">Map<\/span><span style=\"color: #ECEFF4\">&lt;<\/span><span style=\"color: #8FBCBB\">Libro<\/span><span style=\"color: #ECEFF4\">,<\/span><span style=\"color: #D8DEE9FF\"> <\/span><span style=\"color: #8FBCBB\">ArrayList<\/span><span style=\"color: #ECEFF4\">&lt;<\/span><span style=\"color: #8FBCBB\">Integer<\/span><span style=\"color: #ECEFF4\">&gt;&gt;&gt;(){}.<\/span><span style=\"color: #88C0D0\">getType<\/span><span style=\"color: #ECEFF4\">()<\/span><span style=\"color: #81A1C1\">;<\/span><\/span>\n<span class=\"line\"><span style=\"color: #D8DEE9FF\">        <\/span><span style=\"color: #8FBCBB\">Map<\/span><span style=\"color: #ECEFF4\">&lt;<\/span><span style=\"color: #8FBCBB\">Libro<\/span><span style=\"color: #ECEFF4\">,<\/span><span style=\"color: #D8DEE9FF\"> <\/span><span style=\"color: #8FBCBB\">ArrayList<\/span><span style=\"color: #ECEFF4\">&lt;<\/span><span style=\"color: #8FBCBB\">Integer<\/span><span style=\"color: #ECEFF4\">&gt;&gt;<\/span><span style=\"color: #D8DEE9FF\"> <\/span><span style=\"color: #D8DEE9\">mapaRecuperado<\/span><span style=\"color: #D8DEE9FF\"> <\/span><span style=\"color: #81A1C1\">=<\/span><span style=\"color: #D8DEE9FF\"> <\/span><span style=\"color: #D8DEE9\">json<\/span><span style=\"color: #ECEFF4\">.<\/span><span style=\"color: #88C0D0\">fromJson<\/span><span style=\"color: #ECEFF4\">(<\/span><span style=\"color: #D8DEE9FF\">mapaString<\/span><span style=\"color: #ECEFF4\">,<\/span><span style=\"color: #D8DEE9FF\"> tipo<\/span><span style=\"color: #ECEFF4\">)<\/span><span style=\"color: #81A1C1\">;<\/span><\/span>\n<span class=\"line\"><\/span>\n<span class=\"line\"><span style=\"color: #D8DEE9FF\">        <\/span><span style=\"color: #81A1C1\">for<\/span><span style=\"color: #D8DEE9FF\"> <\/span><span style=\"color: #ECEFF4\">(<\/span><span style=\"color: #D8DEE9FF\"> <\/span><span style=\"color: #8FBCBB\">Map<\/span><span style=\"color: #ECEFF4\">.<\/span><span style=\"color: #8FBCBB\">Entry<\/span><span style=\"color: #ECEFF4\">&lt;<\/span><span style=\"color: #8FBCBB\">Libro<\/span><span style=\"color: #ECEFF4\">,<\/span><span style=\"color: #D8DEE9FF\"> <\/span><span style=\"color: #8FBCBB\">ArrayList<\/span><span style=\"color: #ECEFF4\">&lt;<\/span><span style=\"color: #8FBCBB\">Integer<\/span><span style=\"color: #ECEFF4\">&gt;&gt;<\/span><span style=\"color: #D8DEE9FF\"> <\/span><span style=\"color: #D8DEE9\">e<\/span><span style=\"color: #81A1C1\">:<\/span><span style=\"color: #D8DEE9\">mapaRecuperado<\/span><span style=\"color: #ECEFF4\">.<\/span><span style=\"color: #88C0D0\">entrySet<\/span><span style=\"color: #ECEFF4\">()){<\/span><\/span>\n<span class=\"line\"><span style=\"color: #D8DEE9FF\">            <\/span><span style=\"color: #D8DEE9\">System<\/span><span style=\"color: #ECEFF4\">.<\/span><span style=\"color: #D8DEE9\">out<\/span><span style=\"color: #ECEFF4\">.<\/span><span style=\"color: #88C0D0\">println<\/span><span style=\"color: #ECEFF4\">(<\/span><span style=\"color: #D8DEE9\">e<\/span><span style=\"color: #ECEFF4\">.<\/span><span style=\"color: #88C0D0\">getKey<\/span><span style=\"color: #ECEFF4\">())<\/span><span style=\"color: #81A1C1\">;<\/span><\/span>\n<span class=\"line\"><span style=\"color: #D8DEE9FF\">            <\/span><span style=\"color: #8FBCBB\">ArrayList<\/span><span style=\"color: #ECEFF4\">&lt;<\/span><span style=\"color: #8FBCBB\">Integer<\/span><span style=\"color: #ECEFF4\">&gt;<\/span><span style=\"color: #D8DEE9FF\"> <\/span><span style=\"color: #D8DEE9\">notas<\/span><span style=\"color: #D8DEE9FF\"> <\/span><span style=\"color: #81A1C1\">=<\/span><span style=\"color: #D8DEE9FF\"> <\/span><span style=\"color: #D8DEE9\">e<\/span><span style=\"color: #ECEFF4\">.<\/span><span style=\"color: #88C0D0\">getValue<\/span><span style=\"color: #ECEFF4\">()<\/span><span style=\"color: #81A1C1\">;<\/span><\/span>\n<span class=\"line\"><span style=\"color: #D8DEE9FF\">            <\/span><span style=\"color: #D8DEE9\">System<\/span><span style=\"color: #ECEFF4\">.<\/span><span style=\"color: #D8DEE9\">out<\/span><span style=\"color: #ECEFF4\">.<\/span><span style=\"color: #88C0D0\">println<\/span><span style=\"color: #ECEFF4\">(<\/span><span style=\"color: #D8DEE9FF\">notas<\/span><span style=\"color: #ECEFF4\">)<\/span><span style=\"color: #81A1C1\">;<\/span><\/span>\n<span class=\"line\"><span style=\"color: #D8DEE9FF\">        <\/span><span style=\"color: #ECEFF4\">}<\/span><\/span><\/code><\/pre><\/div>\n","protected":false},"excerpt":{"rendered":"<p>Creamos el Map. Recorrer el Map creando un Set. Serializar\/Deserializar<\/p>\n","protected":false},"author":1,"featured_media":185,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[7],"tags":[],"class_list":["post-293","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-java"],"_links":{"self":[{"href":"https:\/\/www.ccorreas.es\/wordpress\/index.php\/wp-json\/wp\/v2\/posts\/293","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.ccorreas.es\/wordpress\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.ccorreas.es\/wordpress\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.ccorreas.es\/wordpress\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.ccorreas.es\/wordpress\/index.php\/wp-json\/wp\/v2\/comments?post=293"}],"version-history":[{"count":0,"href":"https:\/\/www.ccorreas.es\/wordpress\/index.php\/wp-json\/wp\/v2\/posts\/293\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.ccorreas.es\/wordpress\/index.php\/wp-json\/wp\/v2\/media\/185"}],"wp:attachment":[{"href":"https:\/\/www.ccorreas.es\/wordpress\/index.php\/wp-json\/wp\/v2\/media?parent=293"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.ccorreas.es\/wordpress\/index.php\/wp-json\/wp\/v2\/categories?post=293"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.ccorreas.es\/wordpress\/index.php\/wp-json\/wp\/v2\/tags?post=293"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}