動的呼び出しクラスを反射する静的メソッドとインスタンスメソッド

  1 mport java.lang.reflect.Constructor;
  2 import java.lang.reflect.Method;
  3 
  4 
  5 public class CallMethod {
  6 
  7  public static void main(String[] args) throws Exception {
  8   //   TestClass Class  
  9   Class testClass = Class.forName(TestClass.class.getName());
 10 
 11   
 12   // （1）  Class   newInstance        ，               
 13   TestClass objectA = (TestClass) testClass.newInstance();
 14   System.out.println("Class newInstance()       TestClass  : "
 15     + objectA.toString());
 16   // （2）          。                   
 17   Constructor[] cons = testClass.getDeclaredConstructors();
 18   System.out.println("testClass  " + cons.length + "      ");
 19   Constructor con = null;
 20   for (int i = 0; i < cons.length; i++) {
 21    con = cons[i];
 22    //       
 23    if (con.getParameterTypes().length == 0) {
 24     //   Constructor newInstance      
 25     objectA = (TestClass) con.newInstance(null);
 26     System.out
 27       .println("Constructor   newInstance()       TestClass  : "
 28         + objectA.toString());
 29    } else {
 30     //         
 31     objectA = (TestClass) con.newInstance(new Object[] {
 32       new Integer(55), new Integer(88) });
 33     System.out
 34       .println("Constructor   newInstance()         TestClass  : "
 35         + objectA.toString());
 36    }
 37   }
 38 
 39   
 40   //       
 41   Method[] methods = testClass.getMethods();
 42   //              
 43   Method saddMethod1 = testClass.getMethod("sadd", null);
 44   Method addMethod1 = testClass.getMethod("add", null);
 45   //              
 46   Method saddMethod2 = testClass.getMethod("sadd", new Class[] {
 47     int.class, int.class });
 48   Method addMethod2 = testClass.getMethod("add", new Class[] { int.class,
 49     int.class });
 50 
 51   
 52   //            
 53   int result = ((Integer) saddMethod1.invoke(null, null)).intValue();
 54   System.out.println("           sadd: " + result);
 55   //           
 56   result = ((Integer) saddMethod2.invoke(null, new Object[] {
 57     new Integer(30), new Integer(70) })).intValue();
 58   System.out.println("     30, 70     sadd: " + result);
 59 
 60   
 61   objectA = (TestClass) testClass.newInstance();
 62   //            
 63   result = ((Integer) addMethod1.invoke(objectA, null)).intValue();
 64   System.out.println("           add: " + result);
 65   //           
 66   result = ((Integer) addMethod2.invoke(objectA, new Object[] {
 67     new Integer(130), new Integer(170) })).intValue();
 68   System.out.println("     130, 170     add: " + result);
 69 
 70   //         
 71 //  Method sub = testClass.getMethod("sub", null);
 72 //  System.out.println(sub.invoke(objectA, null));
 73  }
 74 
 75  //    
 76  class TestClass {
 77   //       
 78   static int sa = 100;
 79   static int sb = 50;
 80   //       
 81   int a;
 82   int b;
 83   //       
 84   public TestClass() {
 85    this.a = 5;
 86    this.b = 10;
 87   }
 88   //         
 89   public TestClass(int a, int b) {
 90    this.a = a;
 91    this.b = b;
 92   }
 93 
 94   //     ，  add  
 95   public static int sadd() {
 96    return sa + sb;
 97   }
 98   public static int sadd(int a, int b) {
 99    return a + b;
100   }
101   //     ，  add  
102   public int add() {
103    return this.a + this.b;
104   }
105   public int add(int a, int b) {
106    return a + b;
107   }
108   public String toString() {
109    return "a = " + this.a + "; b = " + this.b;
110   }
111   //     
112   private int sub() {
113    return this.a - this.b;
114   }
115  }
116 }