反射类的构造函数

//解剖类的构造函数，创建类的对象  
public class Demo2 {  
      
    //反射构造函数：public Person()  
    @Test  
    public void test1() throws Exception{  
          
        Class clazz = Class.forName("com.marer.reflect.Person");  
        Constructor c = clazz.getConstructor(null);  
          
        Person person = (Person)c.newInstance(null);  
          
        System.out.println(person.str);  
    }  
      
      
      
    //反射构造函数：public Person(String name)  
    @Test  
    public void test2() throws Exception{  
          
        Class clazz = Class.forName("com.marer.reflect.Person");  
        Constructor c = clazz.getConstructor(String.class);  
          
        Person person = (Person)c.newInstance("测试成功");  
          
        System.out.println(person.str);  
    }  
      
      
      
    //反射构造函数：public Person(String name, int age)  
    @Test  
    public void test3() throws Exception{  
          
        Class clazz = Class.forName("com.marer.reflect.Person");  
        Constructor c = clazz.getConstructor(String.class, int.class);  
          
        Person person = (Person)c.newInstance("测试成功",123);  
          
        System.out.println(person.str);  
    }  
      
      
      
    //反射四有的构造函数：private Person(List list)  
    @Test  
    public void test4() throws Exception{  
        Class clazz = Class.forName("com.marer.reflect.Person");  
        Constructor c = clazz.getDeclaredConstructor(List.class);  
          
        c.setAccessible(true);//暴力反射  
          
        Person p = (Person) c.newInstance(new ArrayList());  
          
        System.out.println(p.str);  
    }  
      
      
      
    //创建对象的另外一种途径，反射出类的无参构造函数并创建对象  
    //但是当无参的构造函数为private或不存在的时候，反射抛异常  
    @Test  
    public void test5() throws Exception{  
        Class clazz = Class.forName("com.marer.reflect.Person");  
        Person p = (Person) clazz.newInstance();  
        System.out.println(p);  
        System.out.println(p.str);  
    }  
}