1 package com.coscon.reflectionTest;
2
3 import java.lang.reflect.Method;
4 import java.lang.reflect.ParameterizedType;
5 import java.lang.reflect.Type;
6 import java.util.List;
7 import java.util.Map;
8
9 //用過反射獲取泛型信息
10 public class ReflectionForGenerics {
11 public void test01(Map<String,User> map,List<User> users){
12 System.out.println("test01");
13 }
14
15 public Map<Integer,User> test02(){
16 System.out.println("test02");
17 return null;
18 }
19
20 public static void main(String[] args) {
21 try {
22 Class clazz = Class.forName("com.coscon.reflectionTest.ReflectionForGenerics");
23 //獲得指定方法參數泛型信息
24 Method method = clazz.getMethod("test01", Map.class,List.class);
25 //獲取泛型參數
26 Type[] types = method.getGenericParameterTypes();
27 for (Type type : types) {
28 System.out.println("#"+type);
29 if(type instanceof ParameterizedType){
30 Type[] actualTypeArguments = ((ParameterizedType) type).getActualTypeArguments();
31 for (Type type2 : actualTypeArguments) {
32 System.out.println("泛型參數類型："+type2);
33 }
34 }
35 }
36
37 System.out.println("--------------------------------------------------------------");
38 Method method2 = clazz.getMethod("test02", null);
39 //獲取返回值泛型信息
40 Type returnType = method2.getGenericReturnType();
41 System.out.println("#"+returnType);
42 if(returnType instanceof ParameterizedType){
43 Type[] typeArguments = ((ParameterizedType) returnType).getActualTypeArguments();
44 for (Type type : typeArguments) {
45 System.out.println("返回值泛型類型："+type);
46 }
47 }
48 } catch (Exception e) {
49 // TODO Auto-generated catch block
50 e.printStackTrace();
51 }
52 }
53 }
打印結果
#java.util.Map<java.lang.String, com.coscon.reflectionTest.User>
泛型參數類型：class java.lang.String
泛型參數類型：class com.coscon.reflectionTest.User
#java.util.List<com.coscon.reflectionTest.User>
泛型參數類型：class com.coscon.reflectionTest.User
--------------------------------------------------------------
#java.util.Map<java.lang.Integer, com.coscon.reflectionTest.User>
返回值泛型類型：class java.lang.Integer
返回值泛型類型：class com.coscon.reflectionTest.User
