(window.webpackJsonp=window.webpackJsonp||[]).push([[37],{746:function(s,t,a){"use strict";a.r(t);var n=a(84),e=Object(n.a)({},(function(){var s=this,t=s._self._c;return t("ContentSlotsDistributor",{attrs:{"slot-key":s.$parent.slotKey}},[t("h1",{attrs:{id:"依赖注入"}},[t("a",{staticClass:"header-anchor",attrs:{href:"#依赖注入"}},[s._v("#")]),s._v(" 依赖注入")]),s._v(" "),t("p",[s._v("依赖注入这个名词并没有你想象的那么复杂，实际上它就是把一个类的依赖通过构造函数或者 setter\n方法注入到类中。这样做的好处是，你可以在不修改类的情况下，通过修改容器定义来改变依赖的值。")]),s._v(" "),t("p",[s._v("下方是一个简单的例子，它展示了如何使用依赖注入来获取框架提供的依赖：")]),s._v(" "),t("div",{staticClass:"language-php line-numbers-mode"},[t("pre",{pre:!0,attrs:{class:"language-php"}},[t("code",[t("span",{pre:!0,attrs:{class:"token php language-php"}},[t("span",{pre:!0,attrs:{class:"token delimiter important"}},[s._v("<?php")]),s._v("\n\n"),t("span",{pre:!0,attrs:{class:"token keyword"}},[s._v("use")]),s._v(" "),t("span",{pre:!0,attrs:{class:"token package"}},[s._v("ZM"),t("span",{pre:!0,attrs:{class:"token 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"),t("p",[t("code",[s._v("UserRepositoryInterface")]),s._v("\n定义了从数据库中获取用户信息的方法。对于调用者来说，它并不关心具体的实现类是什么，只需要知道它实现了 "),t("code",[s._v("UserRepositoryInterface")]),s._v("\n接口即可。")]),s._v(" "),t("p",[s._v("因此，我们可以轻易地切换 "),t("code",[s._v("UserRepositoryInterface")]),s._v(" 的实现类，而不需要修改 "),t("code",[s._v("SampleModule")]),s._v("\n类。此外，当需要为该类编写测试时，我们也可以很轻松地模拟或是创建一个伪实现来操作。")]),s._v(" "),t("h2",{attrs:{id:"零配置依赖注入"}},[t("a",{staticClass:"header-anchor",attrs:{href:"#零配置依赖注入"}},[s._v("#")]),s._v(" 零配置依赖注入")]),s._v(" "),t("p",[s._v("如果一个类没有依赖项或只依赖于已经在容器中定义的类，那么你可以不用做任何配置就可以使用依赖注入解析它。")]),s._v(" "),t("p",[s._v("例如：")]),s._v(" "),t("div",{staticClass:"language-php line-numbers-mode"},[t("pre",{pre:!0,attrs:{class:"language-php"}},[t("code",[t("span",{pre:!0,attrs:{class:"token php language-php"}},[t("span",{pre:!0,attrs:{class:"token delimiter important"}},[s._v("<?php")]),s._v("\n\n"),t("span",{pre:!0,attrs:{class:"token keyword"}},[s._v("class")]),s._v(" "),t("span",{pre:!0,attrs:{class:"token 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"),t("div",{staticClass:"line-numbers-wrapper"},[t("span",{staticClass:"line-number"},[s._v("1")]),t("br"),t("span",{staticClass:"line-number"},[s._v("2")]),t("br"),t("span",{staticClass:"line-number"},[s._v("3")]),t("br"),t("span",{staticClass:"line-number"},[s._v("4")]),t("br"),t("span",{staticClass:"line-number"},[s._v("5")]),t("br"),t("span",{staticClass:"line-number"},[s._v("6")]),t("br"),t("span",{staticClass:"line-number"},[s._v("7")]),t("br"),t("span",{staticClass:"line-number"},[s._v("8")]),t("br"),t("span",{staticClass:"line-number"},[s._v("9")]),t("br")])]),t("p",[s._v("在上面的例子中，"),t("code",[s._v("TestService")]),s._v(" 类没有依赖项，因此你可以直接使用依赖注入来解析它：")]),s._v(" "),t("div",{staticClass:"language-php line-numbers-mode"},[t("pre",{pre:!0,attrs:{class:"language-php"}},[t("code",[t("span",{pre:!0,attrs:{class:"token php language-php"}},[t("span",{pre:!0,attrs:{class:"token delimiter important"}},[s._v("<?php")]),s._v("\n\n"),t("span",{pre:!0,attrs:{class:"token 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