反射九:分析性能問題(Java)
1、普通方式調用
2、反射方式調用
3、反射方式調用 關閉檢測
package reflect;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
//分析性能問題
public class Test10 {
//普通方式調用
public static void test01(){
User user=new User();
long startTime=System.currentTimeMillis();
for (int i = 0; i < 1000000000; i++) {
user.getName();
}
long endTime=System.currentTimeMillis();
System.out.println("普通方式執行10億次:"+(endTime-startTime)+"ms");
}
//反射方式調用
public static void test02() throws NoSuchMethodException, InvocationTargetException, IllegalAccessException {
User user=new User();
Class c1 = user.getClass();
Method getName = c1.getDeclaredMethod("getName", null);
long startTime=System.currentTimeMillis();
for (int i = 0; i < 1000000000; i++) {
getName.invoke(user,null);
}
long endTime=System.currentTimeMillis();
System.out.println("反射方式執行10億次:"+(endTime-startTime)+"ms");
}
//反射方式調用 關閉檢測
public static void test03() throws NoSuchMethodException, InvocationTargetException, IllegalAccessException {
User user=new User();
Class c1 = user.getClass();
Method getName = c1.getDeclaredMethod("getName", null);
getName.setAccessible(true);
long startTime=System.currentTimeMillis();
for (int i = 0; i < 1000000000; i++) {
getName.invoke(user,null);
}
long endTime=System.currentTimeMillis();
System.out.println(" 關閉檢測後執行10億次:"+(endTime-startTime)+"ms");
}
public static void main(String[] args) throws NoSuchMethodException, IllegalAccessException, InvocationTargetException {
test01();
test02();
test03();
}
}