简单的Java反射机制

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一. 创建一个简单的java类如下：

package cn.zq;

public class SomeClass {

   /**
   * 转换成小写
   **/
   public void toLower(String s)
   {
       System.out.println("toLower方法");
       System.out.println("原字符："+s);
       System.out.println("转换后："+s.toLowerCase()) ;

   }

   /**
   * 转换成大写
   **/
   public void toUpper(String s)
   {
       System.out.println("toUpper方法");
       System.out.println("原字符："+s);
       System.out.println("转换后："+s.toUpperCase()) ;
   }
}

二. 创建反射类

package cn.zq;

import java.lang.reflect.InvocationTargetException;

public class TestRefl {

   public void test1(String action) throws ClassNotFoundException,
                                            InstantiationException,
                                            IllegalAccessException,
                                            SecurityException,
                                            NoSuchMethodException,
                                            IllegalArgumentException,
                                            InvocationTargetException
   {
       Class clazz = Class.forName(action);

       SomeClass c = (SomeClass) clazz.newInstance();

       c.toUpper("ffff");

       c.toLower("AAAA");


   }



   public static void main(String[] args) throws ClassNotFoundException,
                                                  InstantiationException,
                                                  IllegalAccessException,
                                                  SecurityException,
                                                  NoSuchMethodException,
                                                  IllegalArgumentException,
                                                  InvocationTargetException
   {
          TestRefl tr = new TestRefl();
          tr.test1("cn.zq.SomeClass");
   }
}

结果如图

反射类也可以写成如下

package cn.zq;

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;

public class TestRefl {

    public void test1(String action) throws ClassNotFoundException,
                                            InstantiationException,
                                            IllegalAccessException,
                                            SecurityException,
                                            NoSuchMethodException,
                                            IllegalArgumentException,
                                            InvocationTargetException
    {
       Class clazz = Class.forName(action);

       SomeClass c = (SomeClass) clazz.newInstance();

       Method m = clazz.getMethod("toLower", new Class[]{String.class});

       m.invoke(c, new Object[]{"STR"});

       Method m2 = clazz.getMethod("toUpper", new Class[]{String.class});

       m2.invoke(c, new Object[]{"str"});

    }



    public static void main(String[] args) throws ClassNotFoundException,
                                                  InstantiationException,
                                                  IllegalAccessException,
                                                  SecurityException,
                                                  NoSuchMethodException,
                                                  IllegalArgumentException,
                                                  InvocationTargetException
    {
        TestRefl tr = new TestRefl();
        tr.test1("cn.zq.SomeClass");
    }
}

结果如下

结果显示