反射类的构造函数

 1 import java.lang.reflect.Constructor;
 2 import java.lang.reflect.InvocationTargetException;
 3 import java.util.ArrayList;
 4 import java.util.List;
 5 
 6 import org.junit.Test;
 7 
 8 public class Demo {
 9 
10     /**
11      * 反射类的构造函数，创建类的对象
12      * 
13      * @param args
14      * @throws ClassNotFoundException
15      * @throws Exception
16      * @throws IllegalAccessException
17      * @throws InstantiationException
18      * @throws IllegalArgumentException
19      */
20 
21     // 反射构造函数：public Person()
22     @Test
23     public void test1() throws Exception {
24 
25         Class clazz = Class.forName("Person");
26 
27         Constructor c = clazz.getConstructor(null);
28 
29         Person p = (Person) c.newInstance(null);
30 
31         System.out.println(p.name);
32 
33     }
34 
35     // 反射构造函数：public Person(String name);
36     @Test
37     public void test2() throws Exception {
38         Class clazz = Class.forName("Person");
39 
40         Constructor c = clazz.getConstructor(String.class);
41 
42         Person p = (Person) c.newInstance("xxxxx");
43         
44         System.out.println(p.name);
45 
46     }
47     
48     //public Person(String name,int password){}
49     @Test
50     public void test3() throws Exception {
51         Class clazz = Class.forName("Person");
52 
53         Constructor c = clazz.getConstructor(String.class,int.class);
54 
55         Person p = (Person) c.newInstance("xxxxx",12);
56         
57         System.out.println(p.name);
58 
59     }
60     
61     //public Person(List list){}
62     @Test
63     public void test4() throws Exception {
64         Class clazz = Class.forName("Person");
65 
66         Constructor c = clazz.getDeclaredConstructor(List.class);
67         
68         c.setAccessible(true);//暴力反射，设置可以访问私有
69         
70         Person p = (Person) c.newInstance(new ArrayList());
71         
72         System.out.println(p.name);
73 
74     }
75     
76     //创建对象的另一种方法
77     @Test
78     public void test5() throws Exception {
79         Class clazz = Class.forName("Person");
80       
81         Person p = (Person) clazz.newInstance();
82         
83         System.out.println(p.name);
84 
85     }
86 }

 1 import java.util.List;
 2 
 3 
 4 public class Person {
 5     
 6     public String name="hellowrold";
 7 
 8     public Person(){
 9         System.out.println("person");
10     }
11     
12     public Person(String name){
13         System.out.println("person :"+name);
14     }
15     
16     public Person(String name,int password){
17         System.out.println("person:"+name+password);
18     }
19     
20     private Person(List list){
21         System.out.println("list");
22     }
23 }