{"id":457,"date":"2019-01-19T02:13:03","date_gmt":"2019-01-18T18:13:03","guid":{"rendered":"https:\/\/kaispace.cn\/?p=457"},"modified":"2019-01-19T02:13:03","modified_gmt":"2019-01-18T18:13:03","slug":"mybatis%e8%b8%a9%e5%9d%91%e8%ae%b0%e4%b8%80%e4%b9%8b%e8%87%aa%e5%ae%9a%e4%b9%89typehandler","status":"publish","type":"post","link":"https:\/\/blog.kaispace.cn\/?p=457","title":{"rendered":"MyBatis\u8e29\u5751\u8bb0(\u4e00)\u4e4b\u81ea\u5b9a\u4e49TypeHandler"},"content":{"rendered":"<h1>MyBatis\u8e29\u5751\u8bb0(\u4e00)\u4e4b\u81ea\u5b9a\u4e49TypeHandler<\/h1>\n<p>TypeHandler\u7f51\u4e0a\u7684\u8bb8\u591a\u6587\u7ae0\u90fd\u662f\u5173\u6ce8\u4e8e\u81ea\u5b9a\u4e49\uff0c\u800c\u5e76\u6ca1\u6709\u5173\u6ce8\u5176\u6267\u884c\u8fc7\u7a0b\u3002<\/p>\n<p>TypeHandler\u662f\u7528\u4e8e\u5c06\u6570\u636e\u5e93\u5b57\u6bb5\u4e0eJava\u7c7b\u8fdb\u884c\u8f6c\u6362\u7684\u4e00\u4e2a\u7c7b\uff0c\u5f80\u5f80\u6211\u4eec\u9700\u8981\u81ea\u5b9a\u4e49\u5b9e\u73b0\u5176\u7684\u573a\u666f\u662fJava\u4e2d\u4f7f\u7528\u679a\u4e3e\u7c7b<br \/>\n\u800c\u6570\u636e\u5e93\u4e2d\u7528INTEGER\u6216\u8005CHAR\u53bb\u4ee3\u8868<\/p>\n<p>\u8fd9\u4e2a\u65f6\u5019\u6211\u4eec\u5c31\u9700\u8981\u81ea\u5b9a\u4e49\u4e00\u4e2aTypeHandler\uff0c\u8fd9\u65f6\u5019\u6211\u4eec\u4e00\u822c\u90fd\u662f\u8fd9\u6837\u8bbe\u8ba1<\/p>\n<ul>\n<li>POJO\u5bf9\u5e94\u5c5e\u6027\u7c7b\u578b\u4e3a\u679a\u4e3e\u7c7b\u578b<\/li>\n<li>\u5728SQL Statement\u65f6\u9700\u8981\u5c06\u5c5e\u6027\u8f6c\u4e3a\u6570\u636e\u5e93\u5b57\u6bb5\u8bbe\u8ba1\u7684\u7c7b\u578b ** (Java => \u6570\u636e\u5e93) **<\/li>\n<li>\u5728\u7ed3\u679c\u96c6\u7684\u65f6\u5019\u5c06\u6570\u636e\u5e93\u5b57\u6bb5\u8bbe\u8ba1\u7684\u7c7b\u578b\u8f6c\u6362\u4e3aJava\u7c7b\u578b ** (\u6570\u636e\u5e93 => Java) **<\/li>\n<\/ul>\n<h2>\u81ea\u5b9a\u4e49\u8bbe\u8ba1TypeHandler<\/h2>\n<p>\u8fd9\u65f6\u5019\u6211\u4eec\u53ef\u4ee5\u5229\u7528\u6cdb\u578b\u5199\u51fa\u4e00\u4e2a\u901a\u7528\u7684TypeHandler<\/p>\n<pre><code class=\"language-Java line-numbers\">public final class UniversalEnumHandler &lt;E extends BaseEnum&gt; implements TypeHandler&lt;E&gt; {\n    private Class&lt;E&gt; type;\n    private E [] enums;\n\n    \/**\n     * \u8bbe\u7f6e\u914d\u7f6e\u6587\u4ef6\u8bbe\u7f6e\u7684\u8f6c\u6362\u7c7b\u4ee5\u53ca\u679a\u4e3e\u7c7b\u5185\u5bb9\uff0c\u4f9b\u5176\u4ed6\u65b9\u6cd5\u66f4\u4fbf\u6377\u9ad8\u6548\u7684\u5b9e\u73b0\n     * @param type \u914d\u7f6e\u6587\u4ef6\u4e2d\u8bbe\u7f6e\u7684\u8f6c\u6362\u7c7b\n     *\/\n    public UniversalEnumHandler(Class&lt;E&gt; type) {\n        if (type == null)\n            throw new IllegalArgumentException(\"Type argument cannot be null\");\n        System.out.println(type.toString());\n        this.type = type;\n        this.enums = type.getEnumConstants();\n        if (this.enums == null)\n            throw new IllegalArgumentException(type.getSimpleName()\n                    + \" does not represent an enum type.\");\n    }\n\n    @Override\n    public void setParameter(PreparedStatement preparedStatement, int i, E e, JdbcType jdbcType) throws SQLException {\n        \/\/\u7528getInt\u56e0\u4e3a\u6211\u6570\u636e\u5e93\u91cc\u9762\u662fINTEGER,\u8fd9\u4e2a\u81ea\u5df1\u5224\u65ad,\u4e0b\u9762\u7684\u4e5f\u662f\n        preparedStatement.setInt(i,(int)e.getValue());\n    }\n\n    @Override\n    public E getResult(ResultSet resultSet, String s) throws SQLException {\n        return locateEnumStatus(resultSet.getInt(s));\n    }\n\n    @Override\n    public E getResult(ResultSet resultSet, int i) throws SQLException {\n        return locateEnumStatus(resultSet.getInt(i));\n    }\n\n    @Override\n    public E getResult(CallableStatement callableStatement, int i) throws SQLException {\n        return locateEnumStatus(callableStatement.getInt(i));\n    }\n\n    private E locateEnumStatus(Integer value) {\n        for(E e : enums) {\n            if(e.getValue().equals(value)) {\n                return e;\n            }\n        }\n        throw new IllegalArgumentException(\"\u672a\u77e5\u7684\u679a\u4e3e\u7c7b\u578b\uff1a\" + value + \",\u8bf7\u6838\u5bf9\" + type.getSimpleName());\n    }\n}\n<\/code><\/pre>\n<h2>\u4f7f\u7528TypeHandler<\/h2>\n<ul>\n<li>#{parm}\u4e2d\u6dfb\u52a0\u4e00\u4e2atypeHandler\u5c5e\u6027\u5c31\u53ef\u4ee5\u5728SQL\u8bed\u53e5\u4e2d\u8c03\u7528\u81ea\u5b9a\u4e49\u7684TypeHandler.<\/li>\n<li>@Result\u4e2d\u6dfb\u52a0\u5bf9\u5e94\u5c5e\u6027\u7684typeHandler<\/li>\n<\/ul>\n<h2>\u95ee\u9898\u51fa\u73b0<\/h2>\n<p>\u800c\u6211\u7684POJO\u53ea\u6709\u4e00\u4e2a\u6784\u9020\u5668\uff0c\u662f\u5168\u53c2\u6570\u7684\uff0c\u8fd9\u4e2a\u65f6\u5019\u95ee\u9898\u5c31\u6765\u4e86\uff0c\u8fd9\u6837\u5b50\u662f\u884c\u4e0d\u901a\u7684\uff0c\u56e0\u4e3a\u5728\u63a5\u6536\u5230\u6570\u636e\u5e93\u8fd4\u56de\u7684\u6570\u636e\u65f6\uff0cMybatis\u662f\u5148\u751f\u6210<br \/>\nPOJO\u5bf9\u8c61\uff0c\u518d\u8c03\u7528TypeHandler\u7684getResult\uff0c\u8fd9\u4e2a\u65f6\u5019\u6211\u4eecPOJO\u7684\u5c5e\u6027\u7c7b\u578b\u662f\u679a\u4e3e\u7c7b\uff0c\u8981\u7528INTERGER\u6216\u8005CHAR\u586b\u5145\u8c03\u7528\u6784\u9020\u5668\u80af\u5b9a\u5c31\u62a5\u9519\u4e86<br \/>\n\uff0c\u56e0\u4e3a\u5bf9\u5e94\u5c5e\u6027\u6784\u9020\u5668\u63a5\u6536\u7684\u662f\u679a\u4e3e\u7c7b\u578b\u3002<\/p>\n<p>\u56e0\u6b64\u6b63\u786e\u7684\u65b9\u6cd5\u662f\u518d\u91cd\u8f7d\u4e00\u4e2a\u6784\u9020\u5668\uff0c\u5c06\u5bf9\u5e94\u9700\u8981Maping\u7684\u5c5e\u6027\u5199\u4e3a\u6570\u636e\u5e93\u4e2d\u7684\u5b57\u6bb5\u7c7b\u578b\uff0c\u5728\u6784\u9020\u5668\u4e2d\u653e\u5f03\u8fd9\u4e24\u4e2a\u5c5e\u6027\u7684Setter,\u56e0\u4e3a\u5176\u540eTypeHandler<br \/>\n\u4f1a\u5e2e\u52a9\u4f60\u628a\u4ed6Set\u597d\u3002\u8fd9\u6837\u95ee\u9898\u5c31\u89e3\u51b3\u4e86\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>MyBatis\u8e29\u5751\u8bb0(\u4e00)\u4e4b\u81ea\u5b9a\u4e49TypeHandler TypeHandler\u7f51\u4e0a\u7684\u8bb8\u591a\u6587\u7ae0\u90fd\u662f\u5173\u6ce8\u4e8e\u81ea\u5b9a\u4e49&#8230;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[2,4],"tags":[],"_links":{"self":[{"href":"https:\/\/blog.kaispace.cn\/index.php?rest_route=\/wp\/v2\/posts\/457"}],"collection":[{"href":"https:\/\/blog.kaispace.cn\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blog.kaispace.cn\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blog.kaispace.cn\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/blog.kaispace.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=457"}],"version-history":[{"count":0,"href":"https:\/\/blog.kaispace.cn\/index.php?rest_route=\/wp\/v2\/posts\/457\/revisions"}],"wp:attachment":[{"href":"https:\/\/blog.kaispace.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=457"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blog.kaispace.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=457"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blog.kaispace.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=457"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}