HashMapMain.java

/*
 * Copyright 1999-2012 Alibaba Group.
 * 
 * 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.
 */
package fm.liu.timo.util;

import java.util.HashMap;
import java.util.Map;

/**
 * @author xianmao.hexm
 */
public class HashMapMain {

    public void t() {
        String[] keys = new String[] {"a", "b", "c", "d", "e"};
        long t = System.currentTimeMillis();
        int count = 1000000;
        Map<String, String> m = new HashMap<String, String>();
        t = System.currentTimeMillis();
        for (int i = 0; i < count; i++) {
            for (String key : keys) {
                m.put(key, "String.value");
            }
            for (String key : keys) {
                m.remove(key);
            }
        }
        System.out.println(
                (System.currentTimeMillis() - t) * 1000 * 1000 / (count * keys.length * 2) + " ns");
    }

}