reflection.java

JAVA继承的例子

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

public class ReflectionTest
{
    public static void main(String[] args)
    {
        String name;
        if(args.length>0) name=args[0];
        else
        {
            Scanner in=new Scanner(System.in);
            System.out.println("Enter class name(e.g. java.util.Date):");
            name=in.next();
        }
        
        try
        {
            Class c1=Class.forName(name);
            Class superc1=c1.getSuperclass();
            String modifiers=Modifier.toString(c1.getModifiers());
            if(modifiers.length()>0) System.out.print(modifiers+" ");
            System.out.print("class "+name);
            if(superc1 != null && superc1 != Object.class)
                System.out.print("extends"+superc1.getName());
            
            System.out.print("\n{\n");
            printConstructors(c1);
            System.out.println();
            printMethods(c1);
            System.out.println();
            printFields(c1);
            System.out.println("}");
        }
        
        catch(ClassNotFoundException e)
        {
            e.printStackTrace();
        }
        System.exit(0);
    }
    
    public static void printConstructors(Class c1)
    {
        Constructor[] constructors=c1.getDeclaredConstructors();
        
        for(Constructor c:constructors)
        {
            String name=c.getName();
            System.out.print("  ");
            String modifiers=Modifier.toString(c.getModifiers());
            if(modifiers.length()>0)
                System.out.print(modifiers+" ");
            System.out.print(name+"(");
            
            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(");");
        }
    }
    
    public static void printMethods(Class c1)
    {
        Method[] methods=c1.getDeclaredMethods();
        
        for(Method m:methods)
        {
            Class retType=m.getReturnType();
            String name=m.getName();
            
            System.out.print("  ");
            String modifiers=Modifier.toString(m.getModifiers());
            if(modifiers.length()>0) System.out.print(modifiers+" ");
            System.out.print(retType.getName()+" "+name+"(");
            
            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(");");
        }
    }
    
    public static void printFields(Class c1)
    {
        Field[] fields=c1.getDeclaredFields();
        
        for(Field f:fields)
        {
            Class type=f.getType();
            String name=f.getName();
            System.out.print("  ");
            String modifiers=Modifier.toString(f.getModifiers());
            if(modifiers.length()>0) System.out.print(modifiers+" ");
            System.out.println(type.getName()+" "+name+";");
        }
    }
}