Arrays的常用方法

0.创建/声明一个数组

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

　　1.Java中打印数组

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int[] intArray = { 1, 2, 3, 4, 5 }; String intArrayString = Arrays.toString(intArray);   // print directly will print reference value System.out.println(intArray); // [I@7150bd4d   System.out.println(intArrayString); // [1, 2, 3, 4, 5]

　　2.用数组创建一个ArrayList

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

　　3，检查数组中是否包含特定的值

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

　　4.结合两个数组

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

　　5.声明一个数组的方法

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

　　6，加入所提供的数组中的元素连接成一个字符串

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

　　7. Array与List之间的转换

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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.数组转换成set

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

　　9.数组反向输出

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

　　10.删除数组元素

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int[] intArray = { 1, 2, 3, 4, 5 }; int[] removed = ArrayUtils.removeElement(intArray, 3);//create a new array System.out.println(Arrays.toString(removed));

　　最后一下int转换成byte数组

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