我想用反射调用吸气剂。我这样累了:
for(PropertyDescriptor propertyDescriptor : Introspector.getBeanInfo(this.getClass()).getPropertyDescriptors()){
Method m = propertyDescriptor.getReadMethod();
if(m != null)
System.out.println(m.invoke(this).toString());
}
我总是在调用方法的行中得到NullPointerException。
异常的堆栈跟踪:
org.eclipse.debug.core.DebugException: com.sun.jdi.ClassNotLoadedException: Type has not been loaded occurred while retrieving component type of array.
我搜索了这个问题,但我没有得到解决方案。
答案 0 :(得分:0)
public static void main(String... args) {
if (args.length != 4) {
err.format("Usage: java Deet <classname> <langauge> <country> <variant>%n");
return;
}
try {
Class<?> c = Class.forName(args[0]);
Object t = c.newInstance();
Method[] allMethods = c.getDeclaredMethods();
for (Method m : allMethods) {
String mname = m.getName();
if (!mname.startsWith("test")
|| (m.getGenericReturnType() != boolean.class)) {
continue;
}
Type[] pType = m.getGenericParameterTypes();
if ((pType.length != 1)
|| Locale.class.isAssignableFrom(pType[0].getClass())) {
continue;
}
out.format("invoking %s()%n", mname);
try {
m.setAccessible(true);
Object o = m.invoke(t, new Locale(args[1], args[2], args[3]));
out.format("%s() returned %b%n", mname, (Boolean) o);
// Handle any exceptions thrown by method to be invoked.
} catch (InvocationTargetException x) {
Throwable cause = x.getCause();
err.format("invocation of %s failed: %s%n",
mname, cause.getMessage());
}
}
// production code should handle these exceptions more gracefully
} catch (ClassNotFoundException x) {
x.printStackTrace();
} catch (InstantiationException x) {
x.printStackTrace();
} catch (IllegalAccessException x) {
x.printStackTrace();
}
}