如何获取一个方法的执行时间，不论是静态方法还是静态方法，不论是私有方法还是共有方法，如果该对象不能
被实例化，使用该对象的class对象也可以，例如Arrays.class也可以作为bean传入方法中
只有当方法是static，使用bean和bean.class都可以，但如果不是static，你使用bean.class 会报错
该方法主要用来计算一个方法的执行时间和是否打印方法的执行时间和输出结果，我制作这个方法主要用来比较排序算法的时间复杂度
下面是工具类的代码：
package algorithm.study.utils;
import java.lang.reflect.Method;
/**
* This class is getting a method execute time and provide some other functions.
*
* @author ygh 2017年2月24日
*/
public class MethodExecuteTimeUtils {
/**
* Get a method execute time using millisecond and cancel method's print return result and
* execute time.
*
* @param bean The method is in this bean
* @param params The parameter the method execute need
* @param methodName The name of the method
* @param types The parameter type of the method
* @return The execute time of this method
* @throws Exception If <code>getMethod</code> or <code>invoke</code> fail.
*/
public static long getMethodExecuteTime(Object bean, Object[] params, String methodName, Class<?>[] types)
throws Exception {
return getMethodExecuteTime(bean, params, methodName, types, false, false);
}
/**
* Get a method execute time using millisecond and cancel print method's return result.
*
* @param bean The method is in this bean
* @param params The parameter the method execute need
* @param methodName The name of the method
* @param types The parameter type of the method
* @param isPrintExecutetime Whether print the execute time in console, true is print false not
* @param isViewMehtodResult Whether print the return result in console, true is print false not
* @return The execute time of this method
* @throws Exception If <code>getMethod</code> or <code>invoke</code> fail.
*/
public static long getMethodExecuteTime(Object bean, Object[] params, String methodName,
Class<?>[] types, boolean isPrintExecutetime) throws Exception {
return getMethodExecuteTime(bean, params, methodName, types, isPrintExecutetime, false);
}
/**
* Get a method execute time using millisecond and add some other service.
*
* @param bean The method is in this bean
* @param params The parameter the method execute need
* @param methodName The name of the method
* @param types The parameter type of the method
* @param isPrintExecutetime Whether print the execute time in console, true is print false not
* @param isViewMehtodResult Whether print the return result in console, true is print false not
* @return The execute time of this method
* @throws Exception If <code>getMethod</code> or <code>invoke</code> fail.
*/
public static long getMethodExecuteTime(Object bean, Object[] params, String methodName,
Class<?>[] types, boolean isPrintExecutetime, boolean isViewMehtodResult) throws Exception {
Class<?> clazz;
long executeTime = -1L;
boolean isAccessiable = false;
Method method = null;
if (bean instanceof Class<?>) {
clazz = (Class<?>) bean;
} else {
clazz = bean.getClass();
}
try {
if (types == null) {
method = clazz.getDeclaredMethod(methodName);
} else {
method = clazz.getDeclaredMethod(methodName, types);
}
isAccessiable = method.isAccessible();
if (!isAccessiable) {
method.setAccessible(true);
}
if (isViewMehtodResult) {
executeTime = getReturnMethodExecuteTime(bean, params, method);
} else {
executeTime = getMethodExecuteTime(bean, params, method);
}
method.setAccessible(isAccessiable);
if (isPrintExecutetime) {
printExecute(clazz, methodName, executeTime);
}
} catch (Exception e) {
throw new Exception("excute method fail");
}
return executeTime;
}
/**
* Get a method execute time, use millisecond. We don't think the method whether has a return
* result
*
* @param bean The method is in this bean
* @param params The parameters the method execute need
* @param method The Method entity
* @return The millisecond the method execute spend
* @throws Exception If the method invoke fail
*/
private static long getMethodExecuteTime(Object bean, Object[] params, Method method) throws Exception {
long startTime = System.currentTimeMillis();
method.invoke(bean, params);
long endTime = System.currentTimeMillis();
return endTime - startTime;
}
/**
* Get a method execute time, use millisecond. The method must has a return result will input
* the return result in console ,If the method has not return result, please call
* <code>getMethodExecuteTime</code> method.
*
* @param bean The method is in this bean
* @param params The parameters the method execute need
* @param method The Method entity
* @return The millisecond the method execute spend
* @throws Exception If the method invoke fail
*/
private static long getReturnMethodExecuteTime(Object bean, Object[] params, Method method)
throws Exception {
long startTime = System.currentTimeMillis();
Object result = (Object) method.invoke(bean, params);
long endTime = System.currentTimeMillis();
if (result != null) {
System.out.println("result input：" + result.toString());
} else {
System.out.println("Warning:" + bean.getClass().getName() + "." + method.getName()
+ "has not return " + "result,please setting the isViewMehtodResult as false");
}
return endTime - startTime;
}
/**
* Print the execute time of method
*
* @param methodName The name of the method
* @param time The execute of the method
*/
public static void printExecute(Class<?> clazz, String methodName, long time) {
System.out.println(clazz.getName() + "." + methodName + " execute time: " + time);
}
}测试代码
public class ReflectTest {
@Test
public void fun1() throws Exception {
Person person = new Person();
Object[] params = null;
Class<?>[] types = null;
MethodExecuteTimeUtils.getMethodExecuteTime(person, params, "fun2", types, true, true);
}
@Test
public void fun2() throws Exception {
Person person = new Person();
Object[] params = null;
Class<?>[] types = null;
MethodExecuteTimeUtils.getMethodExecuteTime(person, params, "fun1", types, true, true);
}
@Test
public void fun3() throws Exception {
Person person = new Person();
Object[] params = {12};
Class<?>[] types = {Integer.class};
MethodExecuteTimeUtils.getMethodExecuteTime(person, params, "setAge", types, true, true);
System.out.println(person.getAge());
}
}