[Java 13 类集合] Iterator, Properties, Collections

Iterator

package com.qunar.basicJava.javase.p13_ClassCollection;

import java.util.*;

/**
 * Author: libin.chen@qunar.com  Date: 14-6-11 11:16
 * <p/>
 * * 直接使用 Collection 接口定义的方法 iterator 实例化 Iterator
 */
public class IteratorDemo01 {
    public static void main(String[] args) {
        List<String> list = new ArrayList<String>();
        list.add("hello");
        list.add("-");
        list.add("world!");
        Iterator<String> iterator = list.iterator();
        while (iterator.hasNext()) {
            String str = iterator.next();
            if (str.equals("-")) {
                iterator.remove();
            }
            System.out.print(str + " ");
        }
        System.out.println();
        System.out.println(list); // list 是一个数组
    }
}
/** Output :
 * hello - world!
 * [hello, world!]
 */

Properties

package com.qunar.basicJava.javase.p13_ClassCollection;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.util.Properties;

/**
 * Author: libin.chen@qunar.com  Date: 14-6-11 14:36
 *
 * Properties 类，可以读取属性文件，写入文件，读取xml文件，写入xml文件
 */
public class PropertiesDemo {
    public static void main(String[] args) throws IOException {
        Properties properties = new Properties();
        File file = new File("/home/hp/tmp/config.txt");
        properties.load(new FileInputStream(file));
        System.out.println(properties.getProperty("NJ"));
    }
}

Collections

package com.qunar.basicJava.javase.p13_ClassCollection;

import com.google.common.collect.Lists;

import java.util.Collections;
import java.util.List;

/**
 * Author: libin.chen@qunar.com  Date: 14-6-11 14:12
 *
 * Know : Collections
 */
public class CollectionsDemo01 {
    public static void main(String[] args) {
        /** (1), 常量空容器 */
        List<String> list1 = Collections.emptyList();  // 常量空容器，不可增加元素
        /** (2), 为集合增加内容, 并反转, 检索内容*/
        List<String> list2 = Lists.newArrayList();
        Collections.addAll(list2, "C", "A", "B");
        Collections.reverse(list2);
        System.out.println(list2);

        Collections.addAll(list2, "a", "b", "c");
        int poinnt = Collections.binarySearch(list2,"b");
        System.out.println(poinnt);
        System.out.println(list2);
        /** (3), 替换集合的内容 */
        Collections.replaceAll(list2, "b", "比尔");
        System.out.println(list2);
        /** (4), 交换元素所在位置  */
        Collections.swap(list2, 3, 4);
        System.out.println(list2);

    }
}

输出 ：

[B, A, C]
4
[B, A, C, a, b, c]
[B, A, C, a, 比尔, c]
[B, A, C, 比尔, a, c]