Java程序工具之发射机制类信息打印器（Java版本）

/** * @author Sking * 使用反射机制打印类信息 */package component.ReadAPI;import java.lang.reflect.*;import java.util.*;public class GenericReflectionTest{   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();//从控制台读取指定类      }      try      {           Class<?> cl = Class.forName(name);//返回指定类对应的Class对象         printClass(cl);//打印类声明         for (Method m : cl.getDeclaredMethods())//打印类的所有方法            printMethod(m);      }      catch (ClassNotFoundException e)      {         e.printStackTrace();      }   }   public static void printClass(Class<?> cl)   {      System.out.print(cl);//打印类名，格式为:class 类的完全限定名      printTypes(cl.getTypeParameters(), "<", ", ", ">");//类的类型参数列表      Type sc = cl.getGenericSuperclass(); //返回直接父类的类型      if (sc != null)       {         System.out.print(" extends ");         printType(sc);      }      printTypes(cl.getGenericInterfaces(), " implements ", ", ", "");      System.out.println();   }   public static void printMethod(Method m)   {      String name = m.getName();//方法名　　　 //打印访问修饰符标志的字符串      System.out.print(Modifier.toString(m.getModifiers()));      System.out.print(" ");      printTypes(m.getTypeParameters(), "<", ", ", "> ");//方法类型参数列表      printType(m.getGenericReturnType());//打印返回类型      System.out.print(" ");      System.out.print(name);//打印方法名      System.out.print("(");      printTypes(m.getGenericParameterTypes(), "", ", ", "");//形参类型列表      System.out.println(")");   }    /**    * 按照指定格式打印数组参数指定的类型列表    * @param types 类型数组    * @param pre 格式前缀    * @param sep 类型之间的分隔符    * @param suf 格式后缀    */   public static void printTypes(Type[] types, String pre, String sep, 　　　　　　　　　　　　　　　　　　String suf)   {      if (types.length > 0) System.out.print(pre);//打印前缀      for (int i = 0; i < types.length; i++)      {         if (i > 0) System.out.print(sep);         printType(types[i]);      }      if (types.length > 0) System.out.print(suf);   }   public static void printType(Type type)   {      if (type instanceof Class) //对象类型      {         Class<?> t = (Class<?>) type;         System.out.print(t.getName());      }      else if (type instanceof TypeVariable)//类型变量      {         TypeVariable<?> t = (TypeVariable<?>) type;         System.out.print(t.getName());         printTypes(t.getBounds(), " extends ", " & ", "");      }      else if (type instanceof WildcardType)//通配符类型表达式      {         WildcardType t = (WildcardType) type;         System.out.print("?");         printTypes(t.getLowerBounds(), " extends ", " & ", "");         printTypes(t.getUpperBounds(), " super ", " & ", "");      }      else if (type instanceof ParameterizedType)//参数化类型      {         ParameterizedType t = (ParameterizedType) type;         Type owner = t.getOwnerType();         if (owner != null) { printType(owner); System.out.print("."); }         printType(t.getRawType());         printTypes(t.getActualTypeArguments(), "<", ", ", ">");               }      else if (type instanceof GenericArrayType)//数组类型      {         GenericArrayType t = (GenericArrayType) type;         System.out.print("");         printType(t.getGenericComponentType());         System.out.print("[]");      }        }}