zoukankan      html  css  js  c++  java
  • JAVA基础——Arrays工具类十大常用方法

    Arrays工具类十大常用方法

    原文链接:http://blog.csdn.net/renfufei/article/details/16829457

    0. 声明数组

        String[] aArray = new String[5];  
        String[] bArray = {"a","b","c", "d", "e"};  
        String[] cArray = new String[]{"a","b","c","d","e"};  

    1. 打印数组

        int[] intArray = { 1, 2, 3, 4, 5 };  
        String intArrayString = Arrays.toString(intArray);  
           
        // 直接打印,则会打印出引用对象的Hash值  
        // [I@7150bd4d  
        System.out.println(intArray);  
          
        // [1, 2, 3, 4, 5]  
        System.out.println(intArrayString);  

    2. 根据数组创建ArrayList

        String[] stringArray = { "a", "b", "c", "d", "e" };  
        ArrayList<String> arrayList = new ArrayList<String>(Arrays.asList(stringArray));  
        // [a, b, c, d, e]  
        System.out.println(arrayList);  

    3. 检查数组是否包含某个值

        String[] stringArray = { "a", "b", "c", "d", "e" };  
        boolean b = Arrays.asList(stringArray).contains("a");  
        // true  
        System.out.println(b);  

    4. 合并连接两个数组

        int[] intArray = { 1, 2, 3, 4, 5 };  
        int[] intArray2 = { 6, 7, 8, 9, 10 };  
        // Apache Commons Lang 库  
        int[] combinedIntArray = ArrayUtils.addAll(intArray, intArray2);  

    5. 声明内联数组

        method(new String[]{"a", "b", "c", "d", "e"});  

    6. 用给定的字符串连结(join)数组

        // containing the provided list of elements  
        // Apache common lang  
        String j = StringUtils.join(new String[] { "a", "b", "c" }, ", ");  
        // a, b, c  
        System.out.println(j);  

    7. 将ArrayList转换为数组

        String[] stringArray = { "a", "b", "c", "d", "e" };  
        ArrayList<String> arrayList = new ArrayList<String>(Arrays.asList(stringArray));  
        String[] stringArr = new String[arrayList.size()];  
        arrayList.toArray(stringArr);  
        for (String s : stringArr)  
            System.out.println(s);  

    8. 将数组转换为Set

        Set<String> set = new HashSet<String>(Arrays.asList(stringArray));  
        //[d, e, b, c, a]  
        System.out.println(set);  

    9. 数组元素反转

        int[] intArray = { 1, 2, 3, 4, 5 };  
        ArrayUtils.reverse(intArray);  
        //[5, 4, 3, 2, 1]  
        System.out.println(Arrays.toString(intArray));  

    10. 移除元素

        int[] intArray = { 1, 2, 3, 4, 5 };  
        int[] removed = ArrayUtils.removeElement(intArray, 3);//创建新的数组  
        System.out.println(Arrays.toString(removed));  

    更多——转换int值为字节数组

        byte[] bytes = ByteBuffer.allocate(4).putInt(8).array();  
           
        for (byte t : bytes) {  
           System.out.format("0x%x ", t);  
        }  
    

     相关阅读:

    1. Example of Sorting Arrays
    2. Read bytes from FileInputStream in Java
    3. Java: convert a file to a byte array, then convert byte array to a file.
    4. Top 10 questions about Java Collections
  • 相关阅读:
    Mybatis里面的一对多,一对一查询
    Mybatis简单数据库查询
    tree的使用
    datagrid里面的实现分页功能
    web去掉浏览器自带默认样式
    C#邮件发送
    如何选择正确的标签?
    Table表格的一些操作
    SQL常用分页
    easyui-window
  • 原文地址:https://www.cnblogs.com/hysum/p/7094232.html
Copyright © 2011-2022 走看看