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标题: 直接拿来用！超实用的Java数组技巧攻略 [打印本页]

作者: 潘老板 时间: 2016-11-5 00:03
标题: 直接拿来用！超实用的Java数组技巧攻略
本文分享了关于Java数组最顶级的11大方法，帮助你解决工作流程问题，无论是运用在团队环境或是在私人项目中，你都可以直接拿来用！ 0. 声明一个数组（Declare an array）

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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"};

String[] aArray = new String[5];String[] bArray = {"a","b","c", "d", "e"};String[] cArray = new String[]{"a","b","c","d","e"};1. 在Java中输出一个数组（Print an array in Java）

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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]

int[] intArray = { 1, 2, 3, 4, 5 };String intArrayString = Arrays.toString(intArray); // print directly will print reference valueSystem.out.println(intArray);// [I@7150bd4d System.out.println(intArrayString);// [1, 2, 3, 4, 5]2. 从数组中创建数组列表（Create an ArrayList from an array）

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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]

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值（Check if an array contains a certain value）

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

String[] stringArray = { "a", "b", "c", "d", "e" };boolean b = Arrays.asList(stringArray).contains("a");System.out.println(b);// true4. 连接两个数组（ Concatenate two arrays）
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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);

int[] intArray = { 1, 2, 3, 4, 5 };int[] intArray2 = { 6, 7, 8, 9, 10 };// Apache Commons Lang libraryint[] combinedIntArray = ArrayUtils.addAll(intArray, intArray2);5. 声明一个数组内链（Declare an array inline ）

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

method(new String[]{"a", "b", "c", "d", "e"});6. 将数组元素加入到一个独立的字符串中（Joins the elements of the provided array into a single String）

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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

// containing the provided list of elements// Apache common langString j = StringUtils.join(new String[] { "a", "b", "c" }, ", ");System.out.println(j);// a, b, c7. 将数组列表转换成一个数组（Covnert an ArrayList to an array）

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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);

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. 将数组转换成一个集合（Convert an array to a set）

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

Set<String> set = new HashSet<String>(Arrays.asList(stringArray));System.out.println(set);//[d, e, b, c, a]9. 反向数组（Reverse an array）

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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]

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（Remove element of an array）

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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));

int[] intArray = { 1, 2, 3, 4, 5 };int[] removed = ArrayUtils.removeElement(intArray, 3);//create a new arraySystem.out.println(Arrays.toString(removed));One more – convert int to byte array

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

作者: 雪中鱼01 时间: 2016-11-5 13:12
mark，以后学习～

作者: 江江loves 时间: 2016-11-5 17:22
先收藏了谢楼主分享

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