博客

1.一般用

     System.currentTimeMillis()

2.建议使用Springframework.core.jar中的StopWatch工具类，适用于复杂的场景

package com.example.demo.collections;

/*
 * Copyright 2002-2010 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import java.text.NumberFormat;
import java.util.LinkedList;
import java.util.List;

/**
 * Simple stop watch, allowing for timing of a number of tasks,
 * exposing total running time and running time for each named task.
 *
 * <p>Conceals use of <code>System.currentTimeMillis()</code>, improving the
 * readability of application code and reducing the likelihood of calculation errors.
 *
 * <p>Note that this object is not designed to be thread-safe and does not
 * use synchronization.
 *
 * <p>This class is normally used to verify performance during proof-of-concepts
 * and in development, rather than as part of production applications.
 *
 * @author Rod Johnson
 * @author Juergen Hoeller
 * @author Sam Brannen
 * @since May 2, 2001
 */
public class StopWatch {

    /**
     * Identifier of this stop watch.
     * Handy when we have output from multiple stop watches
     * and need to distinguish between them in log or console output.
     */
    private final String idName;

    private boolean iskeepTaskList = true;

    private final List<TaskInfo> taskList = new LinkedList<TaskInfo>();

    /** Start time of the current task */
    private long startTimeMillis;

    /** Is the stop watch currently running? */
    private boolean running;

    /** Name of the current task */
    private String currentTaskName;

    private TaskInfo lastTaskInfo;

    private int task