好玩的注解和反射

原文地址：http://blog.csdn.net/BingHongChaZuoAn/article/details/52045292

不知道为啥，老觉得注解和反射挺好玩的，以前会写，但是不是玩，没深度，没意思，这次好好没玩一哈。

看下面代码：

注解MM，这是一个方法注解

@Target(ElementType.METHOD)
@Retention(RetentionPolicy.RUNTIME)
public @interface MM {

String name() default "cooci";
int age() default 24;
int order() default 0;
}

注解Boy，这是一个变量注解

@Target(ElementType.FIELD)
@Retention(RetentionPolicy.RUNTIME)
public @interface Boy {
String name () default "";
}

注解主要类

public class TestMM {

@Boy(name = "西门庆")
private String boy1;

@Boy(name = "武大郎")
private String boy2;

@MM(name = "潘金莲",order = 1)
private void moMM(String boyName, String mmName) {
Log.v("invoke", "--------" + boyName + "摸了" + mmName + "一下---------");
}

@MM(name = "潘金莲",order = 2)
private void mmSay(String boyName, String mmName) {
if (boyName.equals("西门庆")) {
Log.v("invoke", "----"+mmName+"说----流氓！-----");
}else if(boyName.equals("武大郎")){
Log.v("invoke", "----"+mmName+"说----滚！-----");
}
}

public String getBoy1() {
return boy1;
}

public String getBoy2() {
return boy2;
}
}

注解辅助类

class MethodHold {
private Method method;
private MM mm;

public MethodHold() {
}

public MethodHold(Method method, MM mm) {
this.method = method;
this.mm = mm;
}

public Method getMethod() {
return method;
}

public void setMethod(Method method) {
this.method = method;
}

public MM getMm() {
return mm;
}

public void setMm(MM mm) {
this.mm = mm;
}
}

测试类

public class MainActivity extends AppCompatActivity {

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);

FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);

fab.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
//                testStudentInvoke();
//                testAppleInvoke();
testMM();

}
});

}

private void testMM() {
Class<?> cls = TestMM.class;
try {

TestMM testMM = (TestMM) cls.newInstance();

Field fields[] = cls.getDeclaredFields();
for (Field field : fields) {
if (field.isAnnotationPresent(Boy.class)) {
Boy boy = field.getAnnotation(Boy.class);
field.setAccessible(true);
field.set(testMM, boy.name());
}
}
Log.v("invoke", "--------boy1-------------->" + testMM.getBoy1());
Log.v("invoke", "--------boy2-------------->" + testMM.getBoy2());

Method methods[] = cls.getDeclaredMethods();
ArrayList<MethodHold> arrayList = new ArrayList<>();
for (Method method : methods) {
if (method.isAnnotationPresent(MM.class)) {
MM mm = method.getAnnotation(MM.class);
method.setAccessible(true);
arrayList.add(new MethodHold(method, mm));
}
}

arrayList = sortMethodByOrder(arrayList);
for (MethodHold methodHold : arrayList) {
methodHold.getMethod().invoke(testMM, testMM.getBoy1(), methodHold.getMm().name());
}

for (MethodHold methodHold : arrayList) {
methodHold.getMethod().invoke(testMM, testMM.getBoy2(), methodHold.getMm().name());
}

} catch (IllegalAccessException e) {
e.printStackTrace();
} catch (InstantiationException e) {
e.printStackTrace();
} catch (InvocationTargetException e) {
e.printStackTrace();
}

}

/**
*标准冒泡排序
*/
private ArrayList<MethodHold> sortMethodByOrder(ArrayList<MethodHold> arrayList) {

for (int i = 0; i < arrayList.size() - 1; i++) {
boolean flag = true;
for (int j = 0; j < arrayList.size() - i - 1; j++) {
MethodHold preMethodHold = arrayList.get(j);
MethodHold aftermethodHold = arrayList.get(j + 1);
if (preMethodHold.getMm().order() > aftermethodHold.getMm().order()) {
arrayList.remove(j);
arrayList.add(j + 1, preMethodHold);
flag = false;
}
}

if (flag) {
break;
}
}
return arrayList;
}
}

就此搞定，看打印的结果：

invoke: --------boy1-------------->西门庆
invoke: --------boy2-------------->武大郎
invoke: --------西门庆摸了潘金莲一下---------
invoke: ----潘金莲说----流氓！-----
invoke: --------武大郎摸了潘金莲一下---------
invoke: ----潘金莲说----滚！-----

好了 ，好玩吧 哈哈，你也试试