利用jOOR简化Java 反射使用
原文: <a href="/misc/goto?guid=4959500886306536866" target="_blank">http://lukaseder.wordpress.com/2011/12/29/a-neater-way-to-use-reflection-in-java/</a> <br /> <br /> Java的反射机制是Java一个非常强大的工具, 但是和大多数脚本语言相比, 使用起来却是有种"懒婆娘的裹脚布——又臭又长"的感觉. <br /> <br /> 比如在PHP语言中, 我们可能这样写: <br /> <br /> <pre class="brush:php; toolbar: true; auto-links: false;">// PHP $method = 'my_method'; $field = 'my_field'; // Dynamically call a method $object->$method(); // Dynamically access a field $object->$field;</pre> <br /> <br /> 在JavaScript语言中, 我们会这样写: <br /> <pre class="brush:javascript; toolbar: true; auto-links: false;">// JavaScript var method = 'my_method'; var field = 'my_field'; // Dynamically call a function object[method](); // Dynamically access a field object[field];</pre> <br /> 在Java中, 我们会这样写: <br /> <br /> <pre class="brush:java; toolbar: true; auto-links: false;">String method = "my_method"; String field = "my_field"; // Dynamically call a method object.getClass().getMethod(method).invoke(object); // Dynamically access a field object.getClass().getField(field).get(object);</pre> <br /> <br /> 上面的代码还没有考虑到对各种异常的处理, 比如NullPointerExceptions, InvocationTargetExceptions, IllegalAccessExceptions, IllegalArgumentExceptions, SecurityExceptions. 以及对基本类型的处理. 但是大部分情况下, 这些都是不需要关心的. <br /> <br /> 为了解决这个问题, 于是有了这个工具: jOOR (Java Object Oriented Reflection). <br /> <br /> 对于这样的Java代码: <br /> <pre class="brush:java; toolbar: true; auto-links: false;">// Classic example of reflection usage try { Method m1 = department.getClass().getMethod("getEmployees"); Employee employees = (Employee[]) m1.invoke(department); for (Employee employee : employees) { Method m2 = employee.getClass().getMethod("getAddress"); Address address = (Address) m2.invoke(employee); Method m3 = address.getClass().getMethod("getStreet"); Street street = (Street) m3.invoke(address); System.out.println(street); } } // There are many checked exceptions that you are likely to ignore anyway catch (Exception ignore) { // ... or maybe just wrap in your preferred runtime exception: throw new RuntimeException(e); }</pre> <br /> <br /> 使用 jOOR的写法: <br /> <br /> <pre class="brush:java; toolbar: true; auto-links: false;">Employee[] employees = on(department).call("getEmployees").get(); for (Employee employee : employees) { Street street = on(employee).call("getAddress").call("getStreet").get(); System.out.println(street); }</pre> <br /> <br /> 在Stack Overflow上相关的问题讨论: <br /> <br /> <a href="/misc/goto?guid=4959500886402918978" target="_blank">http://stackoverflow.com/questions/4385003/java-reflection-open-source/8672186</a> <br /> <br /> 另一个例子: <br /> <br /> <pre class="brush:java; toolbar: true; auto-links: false;">String world = on("java.lang.String") // Like Class.forName() .create("Hello World") // Call the most specific matching constructor .call("substring", 6) // Call the most specific matching method .call("toString") // Call toString() .get() // Get the wrapped object, in this case a String</pre> <br /> <br /> jOOR相关的信息, 请猛击: <br /> <a href="/misc/goto?guid=4959500886487536720" target="_blank">http://code.google.com/p/joor/</a> <br /> <br /> 转自: <a href="/misc/goto?guid=4959500886568197152" target="_blank">http://macrochen.iteye.com/blog/1347172</a>
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