JAVA学習--反射方法操作
24785 ワード
1 //1.
2
3 @Test
4 public void test1(){
5 Class clazz = Person.class;
6 //1.getMethods(): public
7 Method[] m1 = clazz.getMethods();
8 for(Method m : m1){
9 System.out.println(m);
10 }
11 System.out.println();
12
13 //2.getDeclaredMethods():
14 Method[] m2 = clazz.getDeclaredMethods();
15 for(Method m : m2){
16 System.out.println(m);
17 }
18 } 1 //
2 @Test
3 public void test2(){
4 Class clazz = Person.class;
5
6 Method[] m2 = clazz.getDeclaredMethods();
7 for(Method m : m2){
8 //1.
9 Annotation[] ann = m.getAnnotations();
10 for(Annotation a : ann){
11 System.out.println(a);
12 }
13
14 //2.
15 String str = Modifier.toString(m.getModifiers());
16 System.out.print(str + " ");
17 //3.
18 Class returnType = m.getReturnType();
19 System.out.print(returnType.getName() + " ");
20 //4.
21 System.out.print(m.getName() + " ");
22
23 //5.
24 System.out.print("(");
25 Class[] params = m.getParameterTypes();
26 for(int i = 0;i < params.length;i++){
27 System.out.print(params[i].getName() + " args-" + i + " ");
28 }
29 System.out.print(")");
30
31 //6.
32 Class[] exps = m.getExceptionTypes();
33 if(exps.length != 0){
34 System.out.print("throws ");
35 }
36 for(int i = 0;i < exps.length;i++){
37 System.out.print(exps[i].getName() + " ");
38 }
39 System.out.println();
40 }
41 } 1 //
2 @Test
3 public void test3() throws Exception{
4 Class clazz = Person.class;
5 //getMethod(String methodName,Class ... params): public
6 Method m1 = clazz.getMethod("show");
7 Person p = (Person)clazz.newInstance();
8 // ：Object invoke(Object obj,Object ... obj)
9 Object returnVal = m1.invoke(p);//
10 System.out.println(returnVal);//null
11
12 Method m2 = clazz.getMethod("toString");
13 Object returnVal1 = m2.invoke(p);
14 System.out.println(returnVal1);//Person [name=null, age=0]
15 //
16 Method m3 = clazz.getMethod("info");
17 m3.invoke(Person.class);
18
19 //getDeclaredMethod(String methodName,Class ... params):
20 Method m4 = clazz.getDeclaredMethod("display",String.class,Integer.class);
21 m4.setAccessible(true);
22 Object value = m4.invoke(p,"CHN",10);// ：CHN
23 System.out.println(value);//10
24 } 1 class Person extends Creature<String> implements Comparable,MyInterface{
2 public String name;
3 private int age;
4 int id;
5 // ， 。
6 public Person() {
7 super();
8 // System.out.println(" ");
9 }
10 public Person(String name) {
11 super();
12 this.name = name;
13 }
14 private Person(String name, int age) {
15 super();
16 this.name = name;
17 this.age = age;
18 }
19 public String getName() {
20 return name;
21 }
22 public void setName(String name) {
23 this.name = name;
24 }
25 public int getAge() {
26 return age;
27 }
28 public void setAge(int age) {
29 this.age = age;
30 }
31
32 public int getId() {
33 return id;
34 }
35 public void setId(int id) {
36 this.id = id;
37 }
38 @MyAnnotation(value = "abc123")
39 public void show(){
40 System.out.println(" ！");
41 }
42
43 private Integer display(String nation,Integer i) throws Exception{
44 System.out.println(" ：" + nation);
45 return i;
46 }
47 @Override
48 public String toString() {
49 return "Person [name=" + name + ", age=" + age + "]";
50 }
51 @Override
52 public int compareTo(Object o) {
53 // TODO Auto-generated method stub
54 return 0;
55 }
56
57 public static void info(){
58 System.out.println(" ！");
59 }
60
61 class Bird{
62
63 }
64
65 } 1 import static java.lang.annotation.ElementType.CONSTRUCTOR;
2 import static java.lang.annotation.ElementType.FIELD;
3 import static java.lang.annotation.ElementType.LOCAL_VARIABLE;
4 import static java.lang.annotation.ElementType.METHOD;
5 import static java.lang.annotation.ElementType.PARAMETER;
6 import static java.lang.annotation.ElementType.TYPE;
7
8 import java.lang.annotation.Retention;
9 import java.lang.annotation.RetentionPolicy;
10 import java.lang.annotation.Target;
11
12 @Target({TYPE, FIELD, METHOD, PARAMETER, CONSTRUCTOR, LOCAL_VARIABLE})
13 @Retention(RetentionPolicy.RUNTIME)
14 public @interface MyAnnotation {
15 String value();
16 }1 public class Creature<T>{
2 public double weight;
3
4 public void breath(){
5 System.out.println(" ！");
6 }
7 }1 import java.io.Serializable; 2 3 public interface MyInterface extends Serializable{ 4 5 }