问答题 本程序的功能是打印出指定类的所有属性，包括类的构造函数、类的属性变量和类的方法。例如运行程序时指定方法为“java.util.Date”，则打印出类Date的所有信息。
import java.lang.reflect.*;
public class exam_22 {
public static void main(String[] args) throws ClassNotFoundException {
if(args.length＜1) {
System.out.println("请输入类的名称!");
return;
}
______c=Class.forName(args[0]);
print_class(c);
}
public static void print_class (Class c)
{
if(c.isInterface()) {
System.out.print(Modifier.toString(c.getModifiers()) + " " +
typename(c));
}
else if (c.getSuperclass() != null) {
System.out.print(Modifier.toString(c.getModifiers()) + " class " +
typename(c) +
" extends " + typename(c.getSuperclass()));
}
else {
System.out.print(Modifier.toString(c.getModifiers()) + " class " +
typename(c));
}
Class[] interfaces=c.getInterfaces();
if ((interfaces != null)&& (interfaces.length ＞ 0)) {
if (c.isInterface()) System.out.print(" extends ");
else System.out.print(" implements ");
for(int i=0; i ＜ interfaces.length; i++) {
if (i ＞ 0) System.out.print(", ");
System.out.print(typename(interfaces[i]));
}
}
System.out.println(" {");
System.out.prlntln(" // Constructors");
Constructor[] constructors=c.getDeclaredConstructors();
for(int i=0; i ＜ constructors.length; i++)
print_method_or_constructor(constructors[i]);
System.out.println(" // Fields");
Field[] fields=c.getDeclaredFields();
for(int i=0; i ＜ fields.length; i++)
print_field(fields[i]);
System.out.println(" // Methods");
______=c.getDeclaredMethods();
for(int i=0; i ＜ methods.length; i++)
print_method_or_constructor(methods[i]);
System.out.println("}");
}
public static String typename(Class t) {
String brackets=" ";
while(t.isArray()) {
brackets += "[]";
t=t.getComponentType();
}
String name=t.getName();
int pos=name.lastIndexOf(".");
if (pos != -1) name=name.substring(pos+1);
return name + brackets;
}
public static String modifiers(int m) {
if (m == 0) return " ";
else return Modifier.toString(m) + " ";
}
public static void print_field(Field f) {
System.out.println(" " + modifiers(f.getModifiers()) +
typename(f.getType()) + " " + f.getName() + ";");
}
public static void print_method_or_constructor (Member member)
Class returntype=null, parameters[], exceptions[];
if (member instanceof Method) {
Method m=(Method) member;
returntype=m.getReturnType();
parameters=m.getParameterTypes();
exceptions=m.getExceptionTypes();
System.out.print(" " + modifiers(member.getModifiers()) +
typename(returntype) +" "+ member.getName() +
"(");
} else {
Constructor c=(Constructor) member;
parameters=c.getParameterTypes();
exceptions=c.getExceptionTypes();
System.out.print(" " + modifiers(member.getModifiers()) +
typename(c.getDeclaringClass()) + "(");
}
for(int i=0; i ＜ parameters.length; i++) {
if (i ＞ 0) System.out.print(", ");
System.out.print(typename(parameters[i]));
}
System.out.print (")");
if (exceptions.length ＞ 0) System.out.print(" throws ");
for(int i=0; i ＜ exceptions.length; i++) {
if (i ＞ 0) System.out.print(", ");
System.out.print(typename(exceptions[i]));
}
System.out.println(";");
}
}