/* The Reflection Test Class used to realize the functions of
java.lang.reflect, referrenced by Corejava Volume I
Display the fields, constructors, and methods, as well as annotations
and exceptions respectively
by kingmmxtj Nov 20, 2008
http://hi.baidu.com/kingmmxtj
*/
import java.util.*;
import java.lang.reflect.*;
import java.text.*;
import java.lang.annotation.Annotation; // pay attention to differ the java.text.annotation
public class ClassAnalyzer
{
public static void main(String[] args)
{
// read the class u input
String name;
if(args.length > 0)
name = args[0];
else
{
System.out.println(“Enter one class naem(e.g. java.uitl.Date): “);
Scanner in = new Scanner(System.in);
name = in.next();
}
try
{
// print class name and super class name
Class cl = Class.forName(name);
Class supercl = cl.getSuperclass();
System.out.print(“Class ” + name);
if(supercl != null) // if(supercl != null && supercl != Object.class)
System.out.print(” extends ” + supercl.getName());
System.out.print(“n{n”);
// leave 4 blank at the beginning
System.out.println(” ****** Fields of the Class ******”);
printFields(cl);
System.out.println();
System.out.println(” ****** Constructors of the Class ******”);
printConstructors(cl);
System.out.println();
System.out.println(” ****** Methods of the Class ******”);
printMethods(cl);
System.out.println(“}”);
}
catch(ClassNotFoundException e)
{
e.printStackTrace();
}
}
/* print all fields in the class
@param cl a class
*/
public static void printFields(Class cl)
{
Field[] fields = cl.getDeclaredFields();
for(Field f : fields)
{
Class type = f.getType();
String name = f.getName();
System.out.print(” ” + Modifier.toString(f.getModifiers()));
System.out.println(” ” + type.getName() + ” ” + name + “;”);
// print all the annotations in the field
Annotation[] annote = f.getDeclaredAnnotations();
for(int i = 0; i < annote.length; i++)
{
System.out.println(” // ” + annote[i].toString());
}
}
}
/* print all constructors in the class
@param cl a class
*/
public static void printConstructors(Class cl)
{
Constructor[] constructors = cl.getDeclaredConstructors();
for(Constructor c : constructors)
{
String name = c.getName();
System.out.print(” ” + 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.print(“)”);
// print the Exceptions in the constructor
Class[] ex = c.getExceptionTypes();
if(ex.length == 0)
System.out.println(“;”);
else
{
System.out.print(” throws “);
for(int j = 0; j < ex.length; j++)
{
if(j > 0)
System.out.print(“, “);
System.out.print(ex[j].getName());
}
System.out.println(“;”);
}
// print all the annotations in the constructor
Annotation[] annote = c.getDeclaredAnnotations();
for(int i = 0; i < annote.length; i++)
{
System.out.println(” // ” + annote[i].toString());
}
}
}
/* print all methods in the class
@param cl a class
*/
public static void printMethods(Class cl)
{
Method[] methods = cl.getDeclaredMethods();
for(Method m : methods)
{
Class retType = m.getReturnType();
String name = m.getName();
// print modifiers, return value and method name
System.out.print(” ” + Modifier.toString(m.getModifiers()));
System.out.print(” ” + retType.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.print(“)”);
// print the Exceptions in the method
Class[] ex = m.getExceptionTypes();
if(ex.length == 0)
System.out.println(“;”);
else
{
System.out.print(” throws “);
for(int j = 0; j < ex.length; j++)
{
if(j > 0)
System.out.print(“, “);
System.out.print(ex[j].getName());
}
System.out.println(“;”);
}
// print all the annotations in the method
Annotation[] annote = m.getDeclaredAnnotations();
for(int i = 0; i < annote.length; i++)
{
System.out.println(“ // ” + annote[i].toString());
}
}
}
}
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