Java Reflection教程Methods类方法

过Class 的getMethods 可以取的类方法的定义
[java]
Class aClass = ...//obtain class object  
Method[] methods = aClass.getMethods();
Class aClass = ...//obtain class object
Method[] methods = aClass.getMethods();
如果知道类方法的参数类型，则可以使用getMethod 取的对应的方法定义,如：
[java]
Class  aClass = ...//obtain class object  
Method method =
aClass.getMethod("DOSomething", new Class[]{String.class});
Class  aClass = ...//obtain class object
Method method =
aClass.getMethod("DOSomething", new Class[]{String.class});

上例取的方法名为DOSomething 带一个String为参数的方法定义。如果找不到对应的方法，java Reflection 抛出NoSuchMethodException 异常。
如果需要方法的方法不带参数，则使用null 做为getMethod的第二个参数，如下：
[java]
Class  aClass = ...//obtain class object  
Method method =
aClass.getMethod("DOSomething", null);
Class  aClass = ...//obtain class object
Method method =
aClass.getMethod("DOSomething", null);

1. 获取方法的参数和返回值定义
获取参数定义
[java]
Method method = ... // obtain method - see above  
Class[] parameterTypes = method.getParameterTypes();
Method method = ... // obtain method - see above
Class[] parameterTypes = method.getParameterTypes();
获取返回值定义
[java]
Method method = ... // obtain method - see above  
Class returnType = method.getReturnType();
Method method = ... // obtain method - see above
Class returnType = method.getReturnType();
2. 使用Method对象调用该方法
[java]
//get method that takes a String as argument  
Method method = MyObject.class.getMethod("DOSomething", String.class);
  
Object returnValue = method.invoke(null, "parameter-value1");
//get method that takes a String as argument
Method method = MyObject.class.getMethod("DOSomething", String.class);

Object returnValue = method.invoke(null, "parameter-value1");
method.invoke 的调用个参数为该方法对应的类对象，如果方法为static 类型，则使用null,后面的参数为该方法的参数值。


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