Java 反射Reflection

package wym;

import java.lang.reflect.*;
import java.util.*;

public class ReflectionTest {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		String name;
		Scanner in = new Scanner(System.in);
		
		System.out.print("Enter a class name(e.g. java.util.Date): ");
		name = in.next();
		
		//pring class name and supper class name (if != null)
		try {
			Class cl = Class.forName(name);
			Class supperCl = cl.getSuperclass();
			
			System.out.print("Class name: "+name);
			
			if (cl != null && supperCl != Object.class)
				System.out.print("  Extends "+supperCl.getName());
			
			System.out.println("\n{\n");
			
			printConstructors(cl);
			System.out.println();			
			printMethods(cl);
			System.out.println();			
			printFields(cl);
			
			System.out.println("}");
			
		} catch (ClassNotFoundException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		
	}

	private static void printConstructors(Class cl) {
		// TODO Auto-generated method stub
		Constructor[] constructors = cl.getDeclaredConstructors();
		
		for(Constructor c:constructors) {
			String name = c.getName();
			System.out.print("\t"+Modifier.toString(c.getModifiers()));
			System.out.print(" "+name+" (");
			
			//print parameter types
			Class[] paramTypes = c.getParameterTypes();
			for (int j=0;j<paramTypes.length;j++) {
				if(j>0) System.out.print(", ");
				System.out.print(paramTypes[j].getName());
			}
			System.out.println(");");
			
		}
	}
	
	private static void printMethods(Class cl) {
		// TODO Auto-generated method stub
		Method[] methods = cl.getDeclaredMethods();
		
		for(Method m: methods) {
			Class reType = m.getReturnType();
			String name = m.getName();
			
			//print modifier, return type and name
			System.out.print("\t"+Modifier.toString(m.getModifiers()));
			System.out.print(" "+reType.getName()+" "+name+" (");
			
			//print parameter types
			Class[] paramTypes = m.getParameterTypes();
			for (int j=0;j<paramTypes.length;j++) {
				if(j>0) System.out.print(", ");
				System.out.print(paramTypes[j].getName());
			}
			System.out.println(");");
		}
	}
	
	private static void printFields(Class cl) {
		// TODO Auto-generated method stub
		Field[] fields = cl.getDeclaredFields();
		
		for (Field f: fields) {
			Class type = f.getType();
			String name = f.getName();
			
			System.out.print("\t" + Modifier.toString(f.getModifiers()));
			System.out.println(" " + type + " " + name + ";");
		}
	}


}