映射＿方法调用

java的反映机制提供了调用方法的方法．在非映射代码中，如果不实例化就无法调用（非静态）方法．映射机制提供了java.lang.reflect.Method.invoke()方法．如下示例：

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Type;
import java.util.Locale;
import static java.lang.System.out;
import static java.lang.System.err;

public class Deet<T> {
		private boolean testDeet(Locale l) {
				out.format("Locale  = %s, ISO Language Code = %s%n",
										l.getDisplayName(),l.getISO3Language());	
				return true;
		}	
		
		private int testFoo(Locale l) {return 0;}
		private boolean testBar() {return true;}
			
		public static void main(String... args) {
				if(args.length !=4) {
						err.format("Usage:java Deet <classname> <language> <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() return %b%n",mname,(Boolean) o);	
								 	}
								 	catch(InvocationTargetException x) {
								 			Throwable cause = x.getCause();
								 			err.format("invocation of %s failed: %s %n",
								 											mname,cause.getMessage());	
								 	}
						}//for
				}catch(ClassNotFoundException x) {
						x.printStackTrace();	
				}catch(InstantiationException x) {
						x.printStackTrace();	
				}catch(IllegalAccessException x) {
						x.printStackTrace();	
				}
		}
}