java 如何在运行时获取方法的 JavaDoc？
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How to get a JavaDoc of a method at run time?
提问by ahmednabil88
Its easy to get a method Nameof a Classat run time
BUT
How i can get a JavaDocof a method at run time ?
它很容易在运行时获得a method Name，
但是
我如何Class在运行时获得一个方法？ JavaDoc
As the following example
作为下面的例子
Our Class that include JavaDocof our target method
我们的类，包括JavaDoc我们的目标方法
public class MyClass {
/**
*
* @param x value of ....
* @return result of ....
*/
public String myMethod(int x) {
return "any value";
}
}
Our Class that has a main method
我们的类有一个主要方法
public class TestJava {
public static void main(String[] args) {
// get Class method Name at run time
String methodName = MyClass.class.getMethods()[0].getName();
System.out.println(methodName); // will print myMethod
// How to get a JavaDoc of myMethod `method` at run time
// MyClass.class.getMethods()[0].????
// expected to print a JavaDoc of myMethod
}
}
采纳答案by Denys Séguret
You can't : the classfile doesn't contain the comments.
你不能：class文件不包含评论。
A "solution" would be to generate the javadoc as HTML when you build your program and to build an URL from the name of the class and the name of the method. You could also generate the javadoc in a more suitable format than HTML using the doclet API.
“解决方案”是在构建程序时将 javadoc 生成为 HTML，并根据类名和方法名构建 URL。您还可以使用doclet API以比 HTML 更合适的格式生成 javadoc 。
回答by Abhi
The only way to get it at runtime is to use custom annotations.
在运行时获取它的唯一方法是使用自定义注释。
Create a custom annotation class:
创建自定义注解类：
@Retention(RUNTIME)
@Target(value = METHOD)
public @interface ServiceDef {
/**
* This provides description when generating docs.
*/
public String desc() default "";
/**
* This provides params when generating docs.
*/
public String[] params();
}
Use it on a method of a class, e.g.:
在类的方法上使用它，例如：
@ServiceDef(desc = "This is an utility class",
params = {"name - the name","format - the format"})
public void read(String name, String format)
Inspect the annotations via reflection:
通过反射检查注释：
for (Method method : Sample.class.getMethods()) {
if (Modifier.isPublic(method.getModifiers())) {
ServiceDef serviceDef = method.getAnnotation(ServiceDef.class);
if (serviceDef != null) {
String[] params = serviceDef.params();
String descOfMethod = serviceDef.desc();
}
}
}
回答by dnault
Annotation processors have access to the Javadoc comments in the source code. If you have control over the compilation process for the classes whose Javadoc you are interested in, you can use an annotation processor to grab the Javadoc at compile-time and make it available later at runtime.
注释处理器可以访问源代码中的 Javadoc 注释。如果您可以控制您感兴趣的 Javadoc 类的编译过程，您可以使用注释处理器在编译时获取 Javadoc，并使其在运行时可用。
This is the approach used in the therapi-runtime-javadocproject (disclosure: which I authored and am shamelessly plugging).
这是在therapi-runtime-javadoc项目中使用的方法（披露：我创作并无耻地插入）。
回答by Lie Ryan
You can run javadoc programmaticallyand passing options to generate documentation for the class that you want and then parsing the generated document to get the documentation for the method that you want. You will need the source code at runtime because comments are not in the class file.
您可以以编程方式运行 javadoc并传递选项以生成所需类的文档，然后解析生成的文档以获取所需方法的文档。您将在运行时需要源代码，因为注释不在类文件中。
回答by cara
Comments do not have a representation in bytecode, they get stripped out by the compiler and aren't available "at runtime".
注释在字节码中没有表示，它们会被编译器剥离，并且在“运行时”不可用。
