import java.util.Arrays;import java.util.List;/** * fileName: ArrayTester * description: 使用Arrays工具类 * * @author lihaogn-main * @version 1.0 * @date 2019/9/10 20:14 */publicclassArrayTester{publicstaticvoidmain(String[] args){// 1 生成list List<Integer> list= Arrays.asList(1,2,3,4,5,6); List<String> list1= Arrays.asList("zhangsan","lisi","wangwu"); System.out.println(list);// [1, 2, 3, 4, 5, 6] System.out.println(list1);// [zhangsan, lisi, wangwu]// 2 二分搜索，返回下标，没有找到返回-1int[] a={1,2,3,4,5,6};int aa= Arrays.binarySearch(a,2);int aaa= Arrays.binarySearch(a,0); System.out.println(aa);// 1 System.out.println(aaa);// -1// 3 拷贝数组int[] b= Arrays.copyOf(a, a.length); System.out.println(a+": "+ Arrays.toString(a));// [I@1540e19d: [1, 2, 3, 4, 5, 6] System.out.println(b+": "+ Arrays.toString(b));// [I@677327b6: [1, 2, 3, 4, 5, 6]// 拷贝下标[2,a.length)之间的数int[] c= Arrays.copyOfRange(a,2, a.length); System.out.println(Arrays.toString(c));// [3, 4, 5, 6]// 4 比较两个数组内容是否相同 System.out.println(Arrays.equals(a, b));// true// 5 填充数组int[] d=newint[5]; Arrays.fill(d,5); System.out.println(Arrays.toString(d));// [5, 5, 5, 5, 5]// 填充数组e下标[1,3)的值int[] e=newint[5]; Arrays.fill(e,1,3,-1); System.out.println(Arrays.toString(e));// [0, -1, -1, 0, 0]/* * Cumulates, in parallel, each element of the given array in place, * using the supplied function. * * 6 使用提供的函数并行地累积给定数组中的每个元素 */ Arrays.parallelPrefix(e,(x, y)-> x+ y); System.out.println(Arrays.toString(e));// [0, -1, -2, -2, -2] Arrays.parallelPrefix(e,(x, y)-> x*2+ y); System.out.println(Arrays.toString(e));// [0, -1, -4, -10, -22]/* * Sorts the specified array into ascending numerical order. * * 7 将指定数组按升序排列，并行 * */ Arrays.parallelSort(e); System.out.println(Arrays.toString(e));// [-22, -10, -4, -1, 0]int[] f={3,67,1,34,76,2,13};// 可以指定范围，例如 [1,f.length-1) Arrays.parallelSort(f,1, f.length-1); System.out.println(Arrays.toString(f));// [3, 1, 2, 34, 67, 76, 13]/* * Sorts the specified array into ascending numerical order. * 将指定数组按升序排列。 * */int[] g={34,12,54,21,23,75}; Arrays.sort(g); System.out.println(Arrays.toString(g));/* * Set all elements of the specified array, * in parallel, using the provided generator function to compute each element. * * 8 使用提供的生成器函数并行地设置指定数组的所有元素，以计算每个元素。 * */ Arrays.parallelSetAll(e, x-> x+15); System.out.println(Arrays.toString(e));// [15, 16, 17, 18, 19]/* * Set all elements of the specified array, * using the provided generator function to compute each element. * 使用提供的生成器函数来计算每个元素，设置指定数组的所有元素。 * 上面是并行的 * */ Arrays.setAll(e, x-> x+1); System.out.println(Arrays.toString(e));// [1, 2, 3, 4, 5]/* * Returns a sequential IntStream with the specified array as its source. * * 9 返回指定数组作为源的序列IntStream。 * */ Arrays.stream(e).forEach(System.out::print);// 12345 System.out.println(); Arrays.stream(e).map(x-> x+2).filter(x-> x<6).forEach(System.out::print);// 345 System.out.println(); System.out.println(Arrays.toString(e));// [1, 2, 3, 4, 5]int[] h= Arrays.stream(e).map(x-> x+5).toArray(); System.out.println(Arrays.toString(h));// [6, 7, 8, 9, 10]/* * Performs a reduction on the elements of this stream, * using an associative accumulation function, * and returns an OptionalInt describing the reduced value, if any. * * 10 使用关联累加函数对这个流的元素执行一个约简，并返回一个OptionalInt， * 描述约简后的值(如果有的话)。 * */ String res= Arrays.stream(e).reduce((x, y)-> x+ y).toString(); System.out.println(res);// OptionalInt[15]int res1= Arrays.stream(e).reduce((x, y)-> x+ y).getAsInt(); System.out.println(res1);// 15 System.out.println(Arrays.toString(e));// [1, 2, 3, 4, 5] System.out.println(Arrays.stream(e).reduce((x, y)-> x+1).getAsInt());// 5 System.out.println(Arrays.stream(e).reduce((x, y)-> x+ y+1).getAsInt());// 19/* * Performs a reduction on the elements of this stream, * using the provided identity value and an associative accumulation function, * and returns the reduced value. * 使用提供的标识值和关联累积函数对该流的元素执行约简，并返回约简后的值。 * */ System.out.println(Arrays.stream(e).reduce(1,(x, y)-> x+ y));// 16(=15+1) System.out.println(Arrays.stream(e).reduce(4,(x, y)-> x+ y));// 19(=15+4)}}