反射九:分析性能问题(Java)
1、普通方式调用
2、反射方式调用
3、反射方式调用 关闭检测
package reflect;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
//分析性能问题
public class Test10 {
//普通方式调用
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("普通方式执行10亿次:"+(endTime-startTime)+"ms");
}
//反射方式调用
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("反射方式执行10亿次:"+(endTime-startTime)+"ms");
}
//反射方式调用 关闭检测
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(" 关闭检测后执行10亿次:"+(endTime-startTime)+"ms");
}
public static void main(String[] args) throws NoSuchMethodException, IllegalAccessException, InvocationTargetException {
test01();
test02();
test03();
}
}