JAVA基礎——Arrays工具類十大常用方法

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Arrays工具類十大常用方法

　　原文連結:http://blog.csdn.net/renfufei/article/details/16829457

0. 聲明數組

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

1. 列印數組

    int[] intArray = { 1, 2, 3, 4, 5 };      String intArrayString = Arrays.toString(intArray);             // 直接列印,則會列印出引用對象的Hash值      // [[email protected]      System.out.println(intArray);            // [1, 2, 3, 4, 5]      System.out.println(intArrayString);  

2. 根據數組建立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. 檢查數組是否包含某個值

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

4. 合并串連兩個數組

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

5. 聲明內聯數組

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

6. 用給定的字串連結(join)數組

    // 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. 將ArrayList轉換為數組

    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. 將數群組轉換為Set

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

9. 數組元素反轉

    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);//建立新的數組      System.out.println(Arrays.toString(removed));  

更多——轉換int值為位元組數組

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

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JAVA基礎——Arrays工具類十大常用方法