检查数组是否包含某个值的方法

1使用List
public static boolean useList(String[] arr, String targetValue) {
    return Arrays.asList(arr).contains(targetValue);}
2，使用set
public static boolean useSet(String[] arr, String targetValue) {
    Set<String> set = new HashSet<String>(Arrays.asList(arr));
    return set.contains(targetValue);}
3，使用循环判断
public static boolean useLoop(String[] arr, String targetValue) {
    for(String s: arr){
        if(s.equals(targetValue))
            return true;
    }
    return false;
4使用Arrays.binarySearch()
（Arrays.binarySearch()方法只能用于有序数组！！！如果数组无序的话得到的结果就会很奇怪。）
public static boolean useArraysBinarySearch(String[] arr, String targetValue) {
    int a =  Arrays.binarySearch(arr, targetValue);
    if(a > 0)
        return true;
    else
        return false;}



public static void main(String[] args) {
    String[] arr = new String[] {  "CD",  "BC", "EF", "DE", "AB"};

    //use list
    long startTime = System.nanoTime();
    for (int i = 0; i < 100000; i++) {
        useList(arr, "A");
    }
    long endTime = System.nanoTime();
    long duration = endTime - startTime;
    System.out.println("useList:  " + duration / 1000000);

    //use set
    startTime = System.nanoTime();
    for (int i = 0; i < 100000; i++) {
        useSet(arr, "A");
    }
    endTime = System.nanoTime();
    duration = endTime - startTime;
    System.out.println("useSet:  " + duration / 1000000);

    //use loop
    startTime = System.nanoTime();
    for (int i = 0; i < 100000; i++) {
        useLoop(arr, "A");
    }
    endTime = System.nanoTime();
    duration = endTime - startTime;
    System.out.println("useLoop:  " + duration / 1000000);

    //use Arrays.binarySearch()
    startTime = System.nanoTime();
    for (int i = 0; i < 100000; i++) {
        useArraysBinarySearch(arr, "A");
    }
    endTime = System.nanoTime();
    duration = endTime - startTime;
    System.out.println("useArrayBinary:  " + duration / 1000000);}